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1605.05025

The Hourglass Effect in Hierarchical Dependency Networks

Many hierarchically modular systems are structured in a way that resembles an hourglass. This "hourglass effect" means that the system generates many outputs from many inputs through a relatively small number of intermediate modules that are critical for the operation of the entire system, referred to as the waist of the hourglass. We investigate the hourglass effect in general, not necessarily layered, hierarchical dependency networks. Our analysis focuses on the number of source-to-target dependency paths that traverse each vertex, and it identifies the core of a dependency network as the smallest set of vertices that collectively cover almost all dependency paths. We then examine if a given network exhibits the hourglass property or not, comparing its core size with a "flat" (i.e., non-hierarchical) network that preserves the source dependencies of each target in the original network. As a possible explanation for the hourglass effect, we propose the Reuse Preference (RP) model that captures the bias of new modules to reuse intermediate modules of similar complexity instead of connecting directly to sources or low complexity modules. We have applied the proposed framework in a diverse set of dependency networks from technological, natural and information systems, showing that all these networks exhibit the general hourglass property but to a varying degree and with different waist characteristics.

cond-mat/9806299

Asymptotic form of the approach to equilibrium in reversible recombination reactions

The reversible reactions A+A<=>C and A+B<=>C are investigated. From the exact Langevin equations describing our model, we set up a systematic approximation scheme to compute the approach of the density of C particles to its equilibrium value. We show that for sufficiently long time t, this approach takes the form of a power law At^(-d/2), for any dimension d. The amplitude A is also computed exactly, but is expected to be model dependent. For uncorrelated initial conditions, the C density turns out to be a monotonic time function. The cases of correlated initial conditions and unequal diffusion constants are investigated as well. In the former, correlations may break the monotonicity of the density or in some special cases they may change the long time behavior. For the latter, the power law remains valid, only the amplitude changes, even in the extreme case of immobile C particles. We also consider the case of segregated initial condition for which a reaction front is observed, and confirm that its width is governed by mean-field exponent in any dimension.

1306.5483

Topological Symmetry Groups of M\"{o}bius Ladders

We classify all groups which can occur as the orientation preserving topological symmetry group of some embedding of a M\"{o}bius ladder graph in $S^3$.

2008.00971

LRG-BEASTS: Ground-based Detection of Sodium and a Steep Optical Slope in the Atmosphere of the Highly Inflated Hot-Saturn WASP-21b

We present the optical transmission spectrum of the highly inflated Saturn-mass exoplanet WASP-21b, using three transits obtained with the ACAM instrument on the William Herschel Telescope through the LRG-BEASTS survey (Low Resolution Ground-Based Exoplanet Atmosphere Survey using Transmission Spectroscopy). Our transmission spectrum covers a wavelength range of 4635-9000 Angstrom, achieving an average transit depth precision of 197ppm compared to one atmospheric scale height at 246ppm. We detect Na I absorption in a bin width of 30 Angstrom, at >4$\sigma$ confidence, which extends over 100 Angstrom. We see no evidence of absorption from K I. Atmospheric retrieval analysis of the scattering slope indicates it is too steep for Rayleigh scattering from H$_2$, but is very similar to that of HD 189733b. The features observed in our transmission spectrum cannot be caused by stellar activity alone, with photometric monitoring of WASP-21 showing it to be an inactive star. We therefore conclude that aerosols in the atmosphere of WASP-21b are giving rise to the steep slope that we observe, and that WASP-21b is an excellent target for infra-red observations to constrain its atmospheric metallicity.

2307.11994

HTP: Exploiting Holistic Temporal Patterns for Sequential Recommendation

Sequential recommender systems have demonstrated a huge success for next-item recommendation by explicitly exploiting the temporal order of users' historical interactions. In practice, user interactions contain more useful temporal information beyond order, as shown by some pioneering studies. In this paper, we systematically investigate various temporal information for sequential recommendation and identify three types of advantageous temporal patterns beyond order, including absolute time information, relative item time intervals and relative recommendation time intervals. We are the first to explore item-oriented absolute time patterns. While existing models consider only one or two of these three patterns, we propose a novel holistic temporal pattern based neural network, named HTP, to fully leverage all these three patterns. In particular, we introduce novel components to address the subtle correlations between relative item time intervals and relative recommendation time intervals, which render a major technical challenge. Extensive experiments on three real-world benchmark datasets show that our HTP model consistently and substantially outperforms many state-of-the-art models. Our code is publically available at https://github.com/623851394/HTP/tree/main/HTP-main

1809.07665

Dynamic Power Control for Packets with Deadlines

Wireless devices need to adapt their transmission power according to the fluctuating wireless channel in order to meet constraints of delay sensitive applications. In this paper, we consider delay sensitivity in the form of strict packet deadlines arriving in a transmission queue. Packets missing the deadline while in the queue are dropped from the system. We aim at minimizing the packet drop rate under average power constraints. We utilize tools from Lyapunov optimization to find an approximate solution by selecting power allocation. We evaluate the performance of the proposed algorithm and show that it achieves the same performance in terms of packet drop rate with that of the Earliest Deadline First (EDF) when the available power is sufficient. However, our algorithm outperforms EDF regarding the trade-off between packet drop rate and average power consumption.

2302.06158

Commuting upper triangular binary morphisms

A morphism $g$ from the free monoid $X^*$ into itself is called upper triangular if the matrix of $g$ is upper triangular. We characterize all upper triangular binary morphisms $g_1$ and $g_2$ such that $g_1g_2=g_2g_1$.

hep-th/0511089

On the spectra of atoms and hadrons

For relativistic closed systems, an operator is explained which has as stationary eigenvalues the squares of the total cms energies, while the wave function has only half as many components as the corresponding Dirac wave function. The operator's time dependence is generalized to a Klein-Gordon equation. It ensures relativistic kinematics in radiative decays. The new operator is not hermitian.

hep-ph/0606143

Mapping String States into Partons: Form Factors and the Hadron Spectrum in AdS/QCD

New developments in holographic QCD are described in this talk in the context of the correspondence between string states in AdS and light-front wavefunctions of hadronic states in physical space-time.

2212.07295

Maximal Initial Learning Rates in Deep ReLU Networks

Training a neural network requires choosing a suitable learning rate, which involves a trade-off between speed and effectiveness of convergence. While there has been considerable theoretical and empirical analysis of how large the learning rate can be, most prior work focuses only on late-stage training. In this work, we introduce the maximal initial learning rate $\eta^{\ast}$ - the largest learning rate at which a randomly initialized neural network can successfully begin training and achieve (at least) a given threshold accuracy. Using a simple approach to estimate $\eta^{\ast}$, we observe that in constant-width fully-connected ReLU networks, $\eta^{\ast}$ behaves differently from the maximum learning rate later in training. Specifically, we find that $\eta^{\ast}$ is well predicted as a power of depth $\times$ width, provided that (i) the width of the network is sufficiently large compared to the depth, and (ii) the input layer is trained at a relatively small learning rate. We further analyze the relationship between $\eta^{\ast}$ and the sharpness $\lambda_{1}$ of the network at initialization, indicating they are closely though not inversely related. We formally prove bounds for $\lambda_{1}$ in terms of depth $\times$ width that align with our empirical results.

gr-qc/0503012

Detectability of f-mode Unstable Neutron Stars by the Schenberg Spherical Antenna

The Brazilian spherical antenna (Schenberg) is planned to detect high frequency gravitational waves (GWs) ranging from 3.0 kHz to 3.4 kHz. There is a host of astrophysical sources capable of being detected by the Brazilian antenna, namely: core collapse in supernova events; (proto)neutron stars undergoing hydrodynamical instability; f-mode unstable neutron stars, caused by quakes and oscillations; excitation of the first quadrupole normal mode of 4-9 solar mass black holes; coalescence of neutron stars and/or black holes; exotic sources such as bosonic or strange matter stars rotating at 1.6 kHz; and inspiralling of mini black hole binaries. We here address our study in particular to the neutron stars, which could well become f-mode unstable producing therefore GWs. We estimate, for this particular source of GWs, the event rates that in principle can be detected by Schenberg and by the Dutch Mini-Grail antenna.

1801.09074

Modeling of a diffusion with aggregation: rigorous derivation and numerical simulation

In this paper, a diffusion-aggregation equation with delta potential is introduced. Based on the global existence and uniform estimates of solutions to the diffusion-aggregation equation, we also provide the rigorous derivation from a stochastic particle system while introducing an intermediate particle system with smooth interaction potential. The theoretical results are compared to numerical simulations relying on suitable discretization schemes for the microscopic and macroscopic level. In particular, the regime switch where the analytic theory fails is numerically analyzed very carefully and allows for a better understanding of the equation.

2301.01746

An efficient and quantitative phase-field model for elastically heterogeneous two-phase solids based on a partial rank-one homogenization scheme

This paper presents an efficient and quantitative phase-field model for elastically heterogeneous alloys that ensures the two mechanical compatibilities$\unicode{x2014}$static and kinematic, in conjunction with chemical equilibrium within the interfacial region. Our model contrasts with existing phase-field models that either violate static compatibility or interfacial chemical equilibrium or are computationally costly. For computational efficiency, the partial rank-one homogenization (PRH) scheme is employed to enforce both static and kinematic compatibilities at the interface. Moreover, interfacial chemical equilibrium is ensured by replacing the composition field with the diffusion potential field as the independent variable of the model. Its performance is demonstrated by simulating four single-particle and one multi-particle cases for two binary two-phase alloys: Ni-Al $\gamma^{\prime}/\gamma$ and UO$_2$/void. Its accuracy is then investigated against analytical solutions. For the single-particle $\gamma^{\prime}/\gamma$ alloy, we find that the accuracy of the phase-field results remains unaffected for both planar and non-planar geometries when the PRH scheme is employed. Fortuitously, in the UO$_2$/void simulations, despite a strong elastic heterogeneity$\unicode{x2014}$the ratio of Young's modulus of the void phase to that of the UO$_2$ phase is $10^{-4}\unicode{x2014}$we find that the PRH scheme shows significantly better convergence compared to the Voigt-Taylor scheme (VTS) for both planar and non-planar geometries. Nevertheless, for the same interface width range as in the $\gamma^{'}/\gamma$ case, the interface migration in these simulations shows dependence on interface width. Contrary to the $\gamma^{\prime}/\gamma$ simulations, we also find that the simulated elastic fields show deviations from the analytical solution in the non-planar UO$_2$/void case using the PRH scheme.

1509.03339

A Formal C Memory Model for Separation Logic

The core of a formal semantics of an imperative programming language is a memory model that describes the behavior of operations on the memory. Defining a memory model that matches the description of C in the C11 standard is challenging because C allows both high-level (by means of typed expressions) and low-level (by means of bit manipulation) memory accesses. The C11 standard has restricted the interaction between these two levels to make more effective compiler optimizations possible, on the expense of making the memory model complicated. We describe a formal memory model of the (non-concurrent part of the) C11 standard that incorporates these restrictions, and at the same time describes low-level memory operations. This formal memory model includes a rich permission model to make it usable in separation logic and supports reasoning about program transformations. The memory model and essential properties of it have been fully formalized using the Coq proof assistant.

2001.01054

Renormalization of electrons in bilayer cuprate superconductors

The characteristic features of the renormalization of the electrons in the bilayer cuprate superconductors are investigated within the kinetic-energy driven superconductivity. It is shown that the quasiparticle excitation spectrum is split into its bonding and antibonding components due to the presence of the bilayer coupling, with each component that is independent. However, in the underdoped and optimally doped regimes, although the bonding and antibonding electron Fermi surface (EFS) contours deriving from the bonding and antibonding layers are truncated to form the bonding and antibonding Fermi arcs, almost all spectral weights in the bonding and antibonding Fermi arcs are reduced to the tips of the bonding and antibonding Fermi arcs, which in this case coincide with the bonding and antibonding hot spots. These hot spots connected by the scattering wave vectors ${\bf q}_{i} $ construct an octet scattering model, and then the enhancement of the quasiparticle scattering processes with the scattering wave vectors ${\bf q}_{i}$ is confirmed via the result of the autocorrelation of the ARPES spectral intensities. Moreover, the peak-dip-hump (PDH) structure developed in each component of the quasiparticle excitation spectrum along the corresponding EFS is directly related with the peak structure in the quasiparticle scattering rate except for at around the hot spots, where the PDH structure is caused mainly by the bilayer coupling. Although the kink in the quasiparticle dispersion is present all around EFS, when the momentum moves away from the node to the antinode, the kink energy smoothly decreases, while the dispersion kink becomes more pronounced, and in particular, near the cut close to the antinode, develops into a break separating of the fasting dispersing high-energy part of the quasiparticle excitation spectrum from the slower dispersing low-energy part.

1901.11299

Max Weinstein: Physics, Philosophy, Pandeism

This is a brief introduction to the life and ideas of the Lithuanian-German physicist, philosopher and religious thinker Max B. Weinstein, who is today best known for his thoughts concerning so-called pandeism. An accomplished theoretical physicist and characteristic figure in the fin-de-siecle transition of the physical world view, Weinstein contributed to a wide range of physics. He was an early if not unsympathetic critic of Einstein's theory of relativity and Minkowski's formulation of it. In this respect he was unoriginal, but in the broader context of science and humanist culture he was an original thinker. He argued in favour of what he called pandeism, a religious-philosophical view according to which the physical world and the cosmic deity are one and the same.

1208.1292

Comparing Simulations of Rising Flux Tubes Through the Solar Convection Zone with Observations of Solar Active Regions: Constraining the Dynamo Field Strength

We study how active-region-scale flux tubes rise buoyantly from the base of the convection zone to near the solar surface by embedding a thin flux tube model in a rotating spherical shell of solar-like turbulent convection. These toroidal flux tubes that we simulate range in magnetic field strength from 15 kG to 100 kG at initial latitudes of 1 degree to 40 degrees in both hemispheres. This article expands upon Weber, Fan, and Miesch (Astrophys. J., 741, 11, 2011) (Article 1) with the inclusion of tubes with magnetic flux of 10^20 Mx and 10^21 Mx, and more simulations of the previously investigated case of 10^22 Mx, sampling more convective flows than the previous article, greatly improving statistics. Observed properties of active regions are compared to properties of the simulated emerging flux tubes, including: the tilt of active regions in accordance with Joy's Law as in Article 1, and in addition the scatter of tilt angles about the Joy's Law trend, the most commonly occurring tilt angle, the rotation rate of the emerging loops with respect to the surrounding plasma, and the nature of the magnetic field at the flux tube apex. We discuss how these diagnostic properties constrain the initial field strength of the active region flux tubes at the bottom of the solar convection zone, and suggest that flux tubes of initial magnetic field strengths of \geq 40 kG are good candidates for the progenitors of large (10^21 Mx to 10^22 Mx) solar active regions, which agrees with the results from Article 1 for flux tubes of 10^22 Mx. With the addition of more magnetic flux values and more simulations, we find that for all magnetic field strengths, the emerging tubes show a positive Joy's Law trend, and that this trend does not show a statistically significant dependence on the magnetic flux.

2103.16486

Testing general relativity with gravitational-wave catalogs: the insidious nature of waveform systematics

Gravitational-wave observations of binary black holes allow new tests of general relativity to be performed on strong, dynamical gravitational fields. These tests require accurate waveform models of the gravitational-wave signal, otherwise waveform errors can erroneously suggest evidence for new physics. Existing waveforms are generally thought to be accurate enough for current observations, and each of the events observed to date appears to be individually consistent with general relativity. In the near future, with larger gravitational-wave catalogs, it will be possible to perform more stringent tests of gravity by analyzing large numbers of events together. However, there is a danger that waveform errors can accumulate among events: even if the waveform model is accurate enough for each individual event, it can still yield erroneous evidence for new physics when applied to a large catalog. This paper presents a simple linearised analysis, in the style of a Fisher matrix calculation, that reveals the conditions under which the apparent evidence for new physics due to waveform errors grows as the catalog size increases. We estimate that, in the worst-case scenario, evidence for a deviation from general relativity might appear in some tests using a catalog containing as few as 10-30 events above a signal-to-noise ratio of 20. This is close to the size of current catalogs and highlights the need for caution when performing these sorts of experiments.

1109.6151

Broad-band Optical Polarimetric Studies toward the Galactic young star cluster Be 59

We present multiwavelength optical linear polarimetric observations of 69 stars toward the young open cluster Be 59. The observations reveal the presence of three dust layers located at the distances of \sim300, \sim500 and \sim700 pc. The dust layers produce a total polarization Pv \sim 5.5 per cent. The mean values of polarization and polarization angles due to the dust layers are found to increase systematically with distance. We show that polarimetry in combination with the (U - B) - (B - V) colour-colour diagram yields a better identification of cluster members. The polarization measurements suggest that the polarization due the intra-cluster medium is \sim 2.2 per cent. An anomalous reddening law exists for the cluster region, indicating a relatively larger grain size than that in the diffuse ISM. The spatial variation of the polarization and E(B - V) is found to increase with radial distance from the cluster center, whereas the {\theta}v and {\lambda}max are found to decrease with increasing radial distance from the cluster center. About 40 per cent of cluster members show the signatures of either intrinsic polarization or rotation in their polarization angles. There is an indication that the star light of the cluster members might have been depolarized because of non-uniform alignment of dust grains in the foreground dust layers and in the intra-cluster medium.

1605.01124

Super-radiant phase transition in superconducting circuit in thermal equilibrium

We propose a superconducting circuit that shows a super-radiant phase transition (SRPT) in the thermal equilibrium. The existence of the SRPT is confirmed analytically in the limit of an infinite number of artificial atoms. We also perform numerical diagonalization of the Hamiltonian with a finite number of atoms and observe an asymptotic behavior approaching the infinite limit as the number of atoms increases. The SRPT can also be interpreted intuitively in a classical analysis.

q-alg/9709014

Quantum currents realization of the elliptic quantum groups $E_{\tau,\eta}({\frak{sl}}_{2})$

We review the construction by G. Felder and the author of the realization of the elliptic quantum groups of sl(2)-type by quantum currents.

2212.08521

The Yang problem for complete bounded complex submanifolds: a survey

We survey the history as well as recent progress in the Yang problem concerning the existence of complete bounded complex submanifolds of the complex Euclidean spaces. We also point out some open questions on the topic.

0903.3792

Dynamics of Strings between Domain Walls

Configurations of vortex-strings stretched between or ending on domain walls were previously found to be 1/4 BPS states. Among zero modes of string positions, the center of mass of strings in each region between two adjacent domain walls is shown to be non-normalizable whereas the rests are normalizable. We study dynamics of vortex-strings stretched between separated domain walls by using two methods, the moduli space (geodesic) approximation of full 1/4 BPS states and the charged particle approximation for string endpoints in the wall effective action. In the first method we obtain the effective Lagrangian explicitly and find the 90 degree scattering for head-on collision. In the second method the domain wall effective action is assumed to be U(1)^N gauge theory, and we find a good agreement between two methods for well separated strings. This paper is based on our paper arXiv:0810.3495 [hep-th].

1007.1811

On the Capacity of a Class of Cognitive Z-interference Channels

We study a special class of the cognitive radio channel in which the receiver of the cognitive pair does not suffer interference from the primary user. Previously developed general encoding schemes for this channel are complex as they attempt to cope with arbitrary channel conditions, which leads to rate regions that are difficult to evaluate. The focus of our work is to derive simple rate regions that are easily computable, thereby providing more insights into achievable rates and good coding strategies under different channel conditions. We first present several explicit achievable regions for the general discrete memoryless case. We also present an improved outer bound on the capacity region for the case of high interference. We then extend these regions to Gaussian channels. With a simple outer bound we establish a new capacity region in the high-interference regime. Lastly, we provide numerical comparisons between the derived achievable rate regions and the outer bounds.

1807.02582

Gaussian Processes and Kernel Methods: A Review on Connections and Equivalences

This paper is an attempt to bridge the conceptual gaps between researchers working on the two widely used approaches based on positive definite kernels: Bayesian learning or inference using Gaussian processes on the one side, and frequentist kernel methods based on reproducing kernel Hilbert spaces on the other. It is widely known in machine learning that these two formalisms are closely related; for instance, the estimator of kernel ridge regression is identical to the posterior mean of Gaussian process regression. However, they have been studied and developed almost independently by two essentially separate communities, and this makes it difficult to seamlessly transfer results between them. Our aim is to overcome this potential difficulty. To this end, we review several old and new results and concepts from either side, and juxtapose algorithmic quantities from each framework to highlight close similarities. We also provide discussions on subtle philosophical and theoretical differences between the two approaches.

1909.04582

Approximation of curves with piecewise constant or piecewise linear functions

In this paper we compute the Hausdorff distance between sets of continuous curves and sets of piecewise constant or linear discretizations. These sets are Sobolev balls given by the continuous or discrete $L^p$-norm of the derivatives. We detail the suitable discretization or smoothing procedure which are preservative in the sense of these norms. Finally we exhibit the link between Eulerian numbers and the uniformly space knots B-spline used for smoothing.

2008.03821

Meta Resonant Waveguide-Gratings Providing Selective Diffraction

The past decade has witnessed the development of a large variety of new flat optics referred to as metasurfaces [1]. These metasurfaces are relying on arrays of a large variety of phase shifting elements. This article aims at presenting a novel type of flat optics able to perform wavefront shaping and beam redirection with a high wavelength or angular selectivity, as well as an intrinsic polarization selectivity. These new elements are not relying on localized phase-shifting but on a distributed guided-mode, closely linked to Resonant Waveguide Gratings (RWG). These new optical elements are referred to as Meta Resonant Waveguide Gratings (MRWG). MRWGs have intrinsically rather low aspect ratios and can be produced with existing high-throughput manufacturing methods such as hot embossing and physical vapor deposition (PVD), making them industrially attractive. Multiple design options linked to their many degrees of freedom enable a wide range of optical properties, such as color-selective free-space combiners and diffractive couplers configurations. The properties of a simple MRWG are detailed, before unveiling a few variants to discuss the influence of some key design parameters, and providing a general design method for complex arrangements.

1301.2006

Large-scale atomistic density functional theory calculations of phosphorus-doped silicon quantum bits

We present density functional theory calculations of phosphorus dopants in bulk silicon and of several properties relating to their use as spin qubits for quantum computation. Rather than a mixed pseudopotential or a Heitler-London approach, we have used an explicit treatment for the phosphorus donor and examined the detailed electronic structure of the system as a function of the isotropic doping fraction, including lattice relaxation due to the presence of the impurity. Doping electron densities and spin densities are examined in order to study the properties of the dopant electron as a function of the isotropic doping fraction. Doping potentials are also calculated for use in calculations of the scattering cross-sections of the phosphorus dopants, which are important in the understanding of electrically detected magnetic resonance experiments. We find that the electron density around the dopant leads to non-spherical features in the doping potentials, such as trigonal lobes in the (001) plane at energy scales of +12 eV near the nucleus and of -700 meV extending away from the dopants. These features are generally neglected in effective mass theory and will affect the coupling between the donor electron and the phosphorus nucleus. Our density functional calculations reveal detail in the densities and potentials of the dopants which are not evident in calculations that do not include explicit treatment of the phosphorus donor atom and relaxation of the crystal lattice. These details can also be used to parameterize tight-binding models for simulation of large-scale devices.

1810.06354

Independence numbers of some double vertex graphs and pair graphs

The combinatorial properties of double vertex graphs has been widely studied since the 90's. However only very few results are know about the independence number of such graphs. In this paper we obtain the independence numbers of the double vertex graphs of fan graphs and wheel graphs. Also we obtain the independence numbers of the pair graphs, that is a generalization of the double vertex graphs, of some families of graphs.

math/0503696

Abelian functions for trigonal curves of degree four and determinantal formulae in purely trigonal case

This paper gives a natural extension of Frobenius-Stickelberger formula and Kiepert formula to Abelian functions for "Purely Trigonal Curves", especially, of degree four. A description on the theory of Abelian functions for general trigonal curves of degree four is also included.

1905.06735

Translational anomaly of chiral fermions in two dimensions

It is well known that a quantized two-dimensional Weyl fermion coupled to gravity spoils general covariance and breaks the covariant conservation of the energy-momentum tensor. In this brief article, we point out that the quantum conservation of the momentum can also fail in flat spacetime, provided the Weyl fermion is coupled to a time-varying homogeneous electric field. This signals a quantum anomaly of the space-translation symmetry, which has not been highlighted in the literature so far.

1706.07341

Regularization of Discontinuous Foliations: Blowing up and Sliding Conditions via Fenichel Theory

We study the regularization of an oriented 1-foliation $\mathcal{F}$ on $M \setminus \Sigma$ where $M$ is a smooth manifold and $\Sigma \subset M$ is a closed subset, which can be interpreted as the discontinuity locus of $\mathcal{F}$. In the spirit of Filippov's work, we define a sliding and sewing dynamics on the discontinuity locus $\Sigma$ as some sort of limit of the dynamics of a nearby smooth 1-foliation and obtain conditions to identify whether a point belongs to the sliding or sewing regions.

2112.14389

A Distributed Gradient Approach for System Optimal Dynamic Traffic Assignment

This study presents a distributed gradient-based approach to solve system optimal dynamic traffic assignment (SODTA) formulated based on the cell transmission model. The algorithm distributes SODTA into local sub-problems, who find optimal values for their decision variables within an intersection. Each sub-problem communicates with its immediate neighbors to reach a consensus on the values of common decision variables. A sub-problem receives proposed values for common decision variables from all adjacent sub-problems and incorporates them into its own offered values by weighted averaging and enforcing a gradient step to minimize its objective function. Then, the updated values are projected onto the feasible region of the sub-problems. The algorithm finds high quality solutions in all tested scenarios with a finite number of iterations. The algorithm is tested on a case study network under different demand levels and finds solutions with at most a 5% optimality gap.

1504.07446

Phonon spectral function of the one-dimensional Holstein-Hubbard model

We use the continuous-time interaction expansion (CT-INT) quantum Monte Carlo method to calculate the phonon spectral function of the one-dimensional Holstein-Hubbard model at half-filling. Our results are consistent with a soft-mode Peierls transition in the adiabatic regime, and the existence of a central peak related to long-range order in the Peierls phase. We explain a previously observed feature at small momenta in terms of a hybridization of charge and phonon excitations. Tuning the system from a Peierls to a metallic phase with a nonzero Hubbard interaction suppresses the central peak, but a significant renormalization of the phonon dispersion remains. In contrast, the dispersion is only weakly modified in the Mott phase. We discuss finite-size effects, the relation to the dynamic charge structure factor, as well as additional sum rules and their implications. Finally, we reveal the existence of a discrete symmetry in a continuum field theory of the Holstein model, which is spontaneously broken in the Peierls phase.

1411.5392

Collective emotion dynamics in chats with agents, moderators and Bots

Using agent-directed simulations, we investigate fluctuations in the collective emotional states on a chat network where agents interchange messages with a fixed number of moderators and emotional Bot. To design a realistic chat system, the interaction rules and some statistical parameters, as well as the agent's attributes, are inferred from the empirical chat channel \texttt{Ubuntu}. In the simulations, the Bot's emotion is fixed; the moderators tune the level of its activity by passing a fraction $\epsilon$ of messages to the Bot. At $\epsilon \gtrsim 0$, the collective emotional state matching the Bot's emotion polarity gradually arises; the average growth rate of the dominant emotional charge serves as an order parameter. Due to self-organizing effects, the collective dynamics is more explosive when positive emotions arise by positive Bot than the onset of negative emotions in the presence of negative Bot at the same $\epsilon$. Furthermore, when the emotions matching the Bot's emotion polarity are spread over the system, the underlying fractal processes exhibit higher persistence and stronger clustering of events than the processes spreading of emotion polarity opposite to the Bot's emotion. On the other hand, the relaxation dynamics is controlled by the external noise; the related nonextensive parameter, estimated from the statistics of returns, is virtually independent of the Bot's activity level and emotion contents.

2002.12540

UKARA 1.0 Challenge Track 1: Automatic Short-Answer Scoring in Bahasa Indonesia

We describe our third-place solution to the UKARA 1.0 challenge on automated essay scoring. The task consists of a binary classification problem on two datasets | answers from two different questions. We ended up using two different models for the two datasets. For task A, we applied a random forest algorithm on features extracted using unigram with latent semantic analysis (LSA). On the other hand, for task B, we only used logistic regression on TF-IDF features. Our model results in F1 score of 0.812.

1906.07191

Interacting Valley Chern Insulator and its Topological Imprint on Moir\'{e} Superconductors

One salient feature of systems with Moir\'{e} superlattice is that, Chern number of "minibands" originating from each valley of the original graphene Brillouin zone becomes a well-defined quantized number because the miniband from each valley can be isolated from the rest of the spectrum due to the Moir\'{e} potential. Then a Moir\'{e} system with a well-defined valley Chern number can become a nonchiral topological insulator with $U(1) \times Z_3 $ symmetry and a $\mathbb{Z}$ classification at the free fermion level. Here we demonstrate that the strongly interacting nature of the Moir\'{e} system reduces the classification of the valley Chern insulator from $\mathbb{Z}$ to $\mathbb{Z}_3$, and it is topologically equivalent to a bosonic symmetry protected topological state made of local boson operators. We also demonstrate that, even if the system becomes a superconductor when doped away from the valley Chern insulator, the valley Chern insulator still leaves a topological imprint as the localized Majorana fermion zero mode in certain geometric configuration.

2111.12595

Daily variability at milli-arcsecond scales in the radio quiet NLSy1 Mrk 110

The origin of radio emission in the majority of Active Galactic Nuclei (AGN) is still poorly understood. Various competing mechanisms are likely involved in the production of radio emission and precise diagnostic tools are needed to disentangle them, of which variability is among the most powerful. For the first time, we show evidence for significant radio variability at 5 GHz at milli-arcsecond scales on days to weeks time scales in the highly accreting and extremely radio-quiet (RQ) Narrow Line Seyfert 1 (NLSy1) Mrk110. The simultaneous Swift/XRT light curve indicates stronger soft than hard X-ray variability. The short-term radio variability suggests that the GHz emitting region has a size smaller than ~180 Schwarzschild radii. The high brightness temperature and the radio and X-ray variability rule out a star-formation and a disc wind origin. Synchrotron emission from a low-power jet and/or an outflowing corona is then favoured.

0704.2486

Testing the gamma-ray burst variability/peak luminosity correlation on a Swift homogeneous sample

We test the gamma-ray burst correlation between temporal variability and peak luminosity of the $\gamma$-ray profile on a homogeneous sample of 36 Swift/BAT GRBs with firm redshift determination. This is the first time that this correlation can be tested on a homogeneous data sample. The correlation is confirmed, as long as the 6 GRBs with low luminosity (<5x10^{50} erg s^{-1} in the rest-frame 100-1000 keV energy band) are ignored. We confirm that the considerable scatter of the correlation already known is not due to the combination of data from different instruments with different energy bands, but it is intrinsic to the correlation itself. Thanks to the unprecedented sensitivity of Swift/BAT, the variability/peak luminosity correlation is tested on low-luminosity GRBs. Our results show that these GRBs are definite outliers.

1706.06063

Quadratic twists of abelian varieties and disparity in Selmer ranks

We study the parity of 2-Selmer ranks in the family of quadratic twists of a fixed principally polarised abelian variety over a number field. Specifically, we determine the proportion of twists having odd (resp. even) 2-Selmer rank. This generalises work of Klagsbrun--Mazur--Rubin for elliptic curves and Yu for Jacobians of hyperelliptic curves. Several differences in the statistics arise due to the possibility that the Shafarevich--Tate group (if finite) may have order twice a square. In particular, the statistics for parities of 2-Selmer ranks and 2-infinity Selmer ranks need no longer agree and we describe both.

0811.0614

Dispersion $\gamma Z$-box correction to the weak charge of the proton

We consider elastic scattering of electrons off a proton target. The parity violating (PV) asymmetry arises at leading order in $\alpha$ due to interference of $\gamma$ and $Z$ exchange. The radiative corrections to this leading mechanism were calculated in the literature and included in experimental analyses, except for $\gamma Z$ box and cross-box contributions. We present here a dispersion calculation of these corrections in forward kinematics. We demonstrate that at the GeV energies of current PV experiments, such corrections are not suppressed by the small vector weak charge of the electron, as occurs in the atomic PV. Our results suggest that the current theoretical uncertainty in the analysis of the QWEAK experiment might be substantially underestimated, and more accurate account of the dispersion corrections are needed in order to interprete the PV data.

0710.0301

Spacetime: Arena or Reality?

For small values of the mass (in relation to the angular momentum and electric charge), the Kerr-Newman (KN) solution of Einstein equation reduces to a naked singularity of circular shape. By considering the Hawking and Ellis extended interpretation of the KN spacetime, as well as Wheeler's idea of "charge without charge", the non-trivial topological structure of the extended KN spatial section is found to represent gravitational states with half-integral angular momentum. As a consequence, it can be consistently interpreted as a model for the electron-positron system, in which the concepts of mass, charge and spin emerge from the spacetime geometry. According to this model, therefore, instead of a simple arena, spacetime must have a concrete existence, being responsible -- through its highly non-trivial topological structures -- for the building blocks of (at least some of) the existing matter in the universe.

2209.01481

Decomposition of Frobenius pushforwards of line bundles on wonderful compactifications

De Concini-Procesi introduced varieties known as wonderful compactifications, which are smooth projective compactifications of semisimple adjoint groups $G$. We study the Frobenius pushforwards of invertible sheaves on the wonderful compactifications, and in particular its decomposition into locally free subsheaves. We give necessary and sufficient conditions for a specific line bundle to be a direct summand of the Frobenius pushforward of another line bundle, formulated in terms of the weight lattice of $\widetilde{G}$, the universal cover of $G$ (identified with the Picard group of the wonderful compactification). In the case of $G=\mathsf{PSL}_n$, we offer lower bounds on the multiplicities (as direct summands) for those line bundles satisfying the sufficient conditions. We also decompose Frobenius pushforwards of line bundles into a direct sum of vector subbundles, whose ranks are determined by invariants on the weight lattice of $G$. We study a particular block which decomposes as a direct sum of line bundles, and identify the line bundles which appear in this block. Finally, we present two approaches to compute the class of the Frobenius pushforward of line bundles on wonderful compactifications in the rational Grothendieck group and in the rational Chow group.

cond-mat/0402652

Local Geometry of the Fermi Surface and Magnetoacoustic Responce of Two-Dimensional Electron Systems in Strong Magnetic Fields

A semiclassical theory for magnetotrasport in a quantum Hall system near filling factor $\nu = 1/2 $ based on the Composite Fermions physical picture is used to analyze the effect of local flattening of the Composite Fermion Fermi surface (CF-FS) upon magnetoacoustic oscllations. We report on calculations of the velocity shift and attenuation of a surface acoustic wave (SAW) which travels above the two-dimensional electron system, and we show that local geometry of the CF-FS could give rise to noticeable changes in the magnitude and phase of the oscillations. We predict these changes to be revealed in experiments, and to be used in further studies of the shape and symmetries of the CF-FS. Main conclusions reported here could be applied to analyze magnetotransport in quantum Hall systems at higher filling factors $ \nu = 3/2, 5/2 $ provided the Fermi-liquid-like state of the system.

1406.1739

On the Farrell and Jones Warping Deformation

We study the Farrell and Jones Warping Deformation.

1604.00884

AKARI/IRC Near-Infrared Spectral Atlas of Galactic Planetary Nebulae

Near-infrared (2.5-5.0$\,\mu$m) low-resolution ($\lambda/\Delta\lambda{\sim}100$) spectra of 72 Galactic planetary nebulae (PNe) were obtained with the Infrared Camera (IRC) in the post-helium phase. The IRC, equipped with a $1'{\times}1'$ window for spectroscopy of a point source, was capable of obtaining near-infrared spectra in a slit-less mode without any flux loss due to a slit. The spectra show emission features including hydrogen recombination lines and the 3.3-3.5$\,\mu$m hydrocarbon features. The intensity and equivalent width of the emission features were measured by spectral fitting. We made a catalog providing unique information on the investigation of the near-infrared emission of PNe. In this paper, details of the observations and characteristics of the catalog are described.

1501.00619

Outage Probability of Overhearing Amplify-and-Forward Cooperative Relaying

This paper investigates the outage performance of overhearing amplify-and-forward (AF) cooperative relaying, where a source transmits information to its destination through multiple helping overhearing AF relays with space-time network coding (STNC) employed. Firstly, the transmission protocol of such a relaying system, i.e., cooperative relaying with overhearing AF relays based on STNC (STNC-OHAF) is presented. Then, the instantaneous end-to-end SNR expression of STNC-OHAF is analysed. Based on this, an explicit expression of the outage probability for STNC-OHAF over independent but not necessarily identically distributed (i.n.i.d) Rayleigh fading channels is theoretically derived. Numerical results validate our theoretical analysis and show that by introducing overhearing among relays, the outage performance of the system can be greatly improved. It also shows that there is a trade-off between system sum outage capacity and the transmitted number of symbols.

2304.04996

Aging during Phase Separation in Long-Range Ising Model

The kinetics of domain growth and aging in conserved order parameter systems, in the presence of short-range interaction, is widely studied. Due to technical difficulties and lack of resources, regarding computation, the dynamics is still not well established in the cases where long-range interactions are involved. Here we present related results from the Monte Carlo simulations of the two-dimensional long-range Ising model (LRIM). Random initial configurations, for $50:50$ compositions of up and down spins, mimicking high temperature equilibrium states, have been quenched to temperatures inside the coexistence curve. Our analysis of the simulation data, for such a protocol, shows interesting dependence of the aging exponent, $\lambda$, on $\sigma$, the parameter, within the Hamiltonian, that controls the range of interaction. To complement these results, we also discuss simulation outcomes for the growth exponent. The obtained values of $\lambda$ are compared with a well-known result for the lower bounds. For this purpose we have extracted interesting properties of the evolving structure.

quant-ph/0308098

Quantum circuits for single-qubit measurements corresponding to platonic solids

Each platonic solid defines a single-qubit positive operator valued measure (POVM) by interpreting its vertices as points on the Bloch sphere. We construct simple circuits for implementing this kind of measurements and other simple types of symmetric POVMs on one qubit. Each implementation consists of a discrete Fourier transform and some elementary quantum operations followed by an orthogonal measurement in the computational basis.

1604.01203

Correlation lengths in hydrodynamic models of active nematics

We examine the scaling with activity of the emergent length scales that control the nonequilibrium dynamics of an active nematic liquid crystal, using two popular hydrodynamic models that have been employed in previous studies. In both models we find that the chaotic spatio-temporal dynamics in the regime of fully developed active turbulence is controlled by a single active scale determined by the balance of active and elastic stresses, regardless of whether the active stress is extensile or contractile in nature. The observed scaling of the kinetic energy and enstropy with activity is consistent with our single-length scale argument and simple dimensional analysis. Our results provide a unified understanding of apparent discrepancies in the previous literature and demonstrate that the essential physics is robust to the choice of model.

1610.06154

Streamflow forecasting using functional regression

Streamflow, as a natural phenomenon, is continuous in time and so are the meteorological variables which influence its variability. In practice, it can be of interest to forecast the whole flow curve instead of points (daily or hourly). To this end, this paper introduces the functional linear models and adapts it to hydrological forecasting. More precisely, functional linear models are regression models based on curves instead of single values. They allow to consider the whole process instead of a limited number of time points or features. We apply these models to analyse the flow volume and the whole streamflow curve during a given period by using precipitations curves. The functional model is shown to lead to encouraging results. The potential of functional linear models to detect special features that would have been hard to see otherwise is pointed out. The functional model is also compared to the artificial neural network approach and the advantages and disadvantages of both models are discussed. Finally, future research directions involving the functional model in hydrology are presented.

0802.1819

Generation of Multiple Circular Walls on a Thin Film of Nematic Liquid Crystal by Laser Scanning

We found that multiple circular walls (MCW) can be generated on a thin film of a nematic liquid crystal through a spiral scanning of a focused IR laser. The ratios between radii of adjacent rings of MCW were almost constant. These constant ratios can be explained theoretically by minimization of the Frank elastic free energy of nematic medium. The director field on a MCW exhibits chiral symmetry-breaking although the elastic free energies of both chiral MCWs are degenerated, i.e., the director on a MCW can rotate clockwise or counterclockwise along the radial direction.

2011.01097

Enabling Zero-shot Multilingual Spoken Language Translation with Language-Specific Encoders and Decoders

Current end-to-end approaches to Spoken Language Translation (SLT) rely on limited training resources, especially for multilingual settings. On the other hand, Multilingual Neural Machine Translation (MultiNMT) approaches rely on higher-quality and more massive data sets. Our proposed method extends a MultiNMT architecture based on language-specific encoders-decoders to the task of Multilingual SLT (MultiSLT). Our method entirely eliminates the dependency from MultiSLT data and it is able to translate while training only on ASR and MultiNMT data. Our experiments on four different languages show that coupling the speech encoder to the MultiNMT architecture produces similar quality translations compared to a bilingual baseline ($\pm 0.2$ BLEU) while effectively allowing for zero-shot MultiSLT. Additionally, we propose using an Adapter module for coupling the speech inputs. This Adapter module produces consistent improvements up to +6 BLEU points on the proposed architecture and +1 BLEU point on the end-to-end baseline.

2310.02891

Large-time behavior of two families of operators related to the fractional Laplacian on certain Riemannian manifolds

This note is concerned with two families of operators related to the fractional Laplacian, the first arising from the Caffarelli-Silvestre extension problem and the second from the fractional heat equation. They both include the Poisson semigroup. We show that on a complete, connected, and non-compact Riemannian manifold of non-negative Ricci curvature, in both cases, the solution with $L^1$ initial data behaves asymptotically as the mass times the fundamental solution. Similar long-time convergence results remain valid on more general manifolds satisfying the Li-Yau two-sided estimate of the heat kernel. The situation changes drastically on hyperbolic space, and more generally on rank one non-compact symmetric spaces: we show that for the Poisson semigroup, the convergence to the Poisson kernel fails -but remains true under the additional assumption of radial initial data.

0811.3656

Ferrotoroidic Moment as a Quantum Geometric Phase

We present a geometric characterization of the ferrotoroidic moment in terms of a set of Abelian Berry phases. We also introduce a fundamental complex quantity which provides an alternative way to calculate the ferrotoroidic moment and its moments, and is derived from a second order tensor. This geometric framework defines a natural computational approach for density functional and many-body theories.

1605.05691

Adsorption of polyelectrolytes on silica and gold surfaces

The results of a study that helps understand the mechanisms of adsorption of polyelectrolytes on particles, using numerical simulation methods, specifically the one known as dissipative particle dynamics are reported here. The adsorption of cationic polyelectrolytes of two different polymerization degrees interacting with two types of surfaces, one made of gold and the other of silica is predicted and compared. We find that a more negatively charged wall does not necessarily adsorb more cationic polyelectrolytes because the electrostatic repulsion between the wall and the polyelectrolytes is stronger. Additionally, intra chain repulsion plays an important role, because the largest polyelectrolyte chains have larger excluded volume than the shorter ones. In regard to the adsorption dependence on the polyelectrolyte polymerization degree we find that the excluded volume drives the adsorption throughout the intrachain electrostatic repulsion, because the SiO2 surface is strongly negative. These results are expected to be useful for several nanotechnological applications of current interest, such as in gene therapy and in the improvement of drug delivering mechanisms.

2212.02334

Estimating Multi-Modal Dense Multipath Components using Auto-Encoders

We present a maximum-likelihood estimation algorithm for radio channel measurements exhibiting a mixture of independent Dense Multipath Components. The novelty of our approach is in the algorithms initialization using a deep learning architecture. Currently, available approaches can only deal with scenarios where a single mode is present. However, in measurements, two or more modes are often observed. This much more challenging multi-modal setting bears two important questions: How many modes are there, and how can we estimate those? To this end, we propose a Neural Net-architecture that can reliably estimate the number of modes present in the data and also provide an initial assessment of their shape. These predictions are used to initialize for gradient- and model-based optimization algorithm to further refine the estimates. We demonstrate numerically how the presented architecture performs on measurement data and analytically study its influence on the estimation of specular paths in a setting where the single-modal approach fails.

nlin/0503020

Wave interactions and the analysis of the perturbed Burgers equation

In multiple-front solutions of the Burgers equation, all the fronts, except for two, are generated through the inelastic interaction of exponential wave solutions of the Lax pair associated with the equation. The inelastically generated fronts are the source of two difficulties encountered in the standard Normal Form expansion of the approximate solution of the perturbed Burgers equation, when the zero-order term is a multiple-front solution: (i) The higher-order terms in the expansion are not bounded; (ii) The Normal Form (equation obeyed by the zero-order approximation) is not asymptotically integrable; its solutions lose the simple wave structure of the solutions of the un-perturbed equation. The freedom inherent in the Normal Form method allows a simple modification of the expansion procedure, making it possible to overcome both problems in more than one way. The loss of asymptotic integrability is shifted from the Normal Form to the higher-order terms (part of which has to be computed numerically) in the expansion of the solution. The front-velocity update is different from the one obtained in the standard analysis.

1307.7881

Modeling Dipolar Post-Shock Accretion Columns for Various Specific Accretion Rate Intermediate Polars

We model the post-shock accretion column (PSAC) for intermediate polars (IPs), with parameterizing specific accretion rate between 0.0001 and 100 g cm-2 s-1 and metal abundance between 0.1 and 2 times of solar abundance, and taking into account the gravitational potential and non-equipartition between ions, electrons and ionization degree. We assume the cylinder and dipole as geometry of the PSAC. The PSAC becomes higher against the white dwarf (WD) radius for lower specific accretion rate and more massive WD, and may be comparable to the WD radius. The consideration of the dipolar geometry significantly reduces the density and temperature over the whole PSAC comparing with the cylindrical case when the specific accretion rate is lower than a threshold which the PSAC height reachs 0.2 RWD with and is decreased by the more massive white dwarf. We calculate the spectra of the cylindrical and dipolar PSACs with the wide range of the specific accretion rate. Although the spectra soften as the specific accretion rate decreases for the both geometrical assumptions under the specific accretion rate threshold, the softening is more speedy for the dipolar PSAC. The fact means that the both geometrical assumptions lead the different WD masses for each other when their spectra are applied to the IPs hosting the low accretion or a massive WD. Although the ionization non-equilibrium are also involved for the spectral calculation, the effects are trivial because the radiation from ionization non-equilibrium plasma is a few percent of the whole at most.

1712.01518

Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab: an update on PR12-16-001

This document is an update to the proposal PR12-16-001 Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab submitted to JLab-PAC44 in 2016 reporting progress in addressing questions raised regarding the beam-on backgrounds. The concerns are addressed by adopting a new simulation tool, FLUKA, and planning measurements of muon fluxes from the dump with its existing shielding around the dump. First, we have implemented the detailed BDX experimental geometry into a FLUKA simulation, in consultation with experts from the JLab Radiation Control Group. The FLUKA simulation has been compared directly to our GEANT4 simulations and shown to agree in regions of validity. The FLUKA interaction package, with a tuned set of biasing weights, is naturally able to generate reliable particle distributions with very small probabilities and therefore predict rates at the detector location beyond the planned shielding around the beam dump. Second, we have developed a plan to conduct measurements of the muon ux from the Hall-A dump in its current configuration to validate our simulations.

0705.4290

The Gemini Deep Planet Survey -- GDPS

We present the results of the Gemini Deep Planet Survey, a near-infrared adaptive optics search for giant planets and brown dwarfs around nearby young stars. The observations were obtained with the Altair adaptive optics system at the Gemini North telescope and angular differential imaging was used to suppress the speckle noise of the central star. Detection limits for the 85 stars observed are presented, along with a list of all faint point sources detected around them. Typically, the observations are sensitive to angular separations beyond 0.5" with 5-sigma contrast sensitivities in magnitude difference at 1.6 micron of 9.5 at 0.5", 12.9 at 1", 15.0 at 2", and 16.5 at 5". For the typical target of the survey, a 100 Myr old K0 star located 22 pc from the Sun, the observations are sensitive enough to detect planets more massive than 2 Mjup with a projected separation in the range 40-200 AU. Second epoch observations of 48 stars with candidates (out of 54) have confirmed that all candidates are unrelated background stars. A detailed statistical analysis of the survey results, yielding upper limits on the fractions of stars with giant planet or low mass brown dwarf companions, is presented. Assuming a planet mass distribution dN/dm m^{-1.2} and a semi-major axis distribution dN/da a^{-1}, the 95% credible upper limits on the fraction of stars with at least one planet of mass 0.5-13 Mjup are 0.28 for the range 10-25 AU, 0.13 for 25-50 AU, and 0.093 for 50-250 AU. The 95% credible interval for the fraction of stars with at least one brown dwarf companion having a semi-major axis in the range 25-250 AU is 0.019 (-0.015/+0.083), irrespective of any assumption on the mass and semi-major axis distributions. The stars HD 14802, HD 166181, and HD 213845 have been resolved into binaries for the first time.

1803.03498

Efficient calculation of open quantum system dynamics and time-resolved spectroscopy with Distributed Memory HEOM (DM-HEOM)

Time- and frequency resolved optical signals provide insights into the properties of light harvesting molecular complexes, including excitation energies, dipole strengths and orientations, as well as in the exciton energy flow through the complex. The hierarchical equations of motion (HEOM) provide a unifying theory, which allows one to study the combined effects of system-environment dissipation and non-Markovian memory without making restrictive assumptions about weak or strong couplings or separability of vibrational and electronic degrees of freedom. With increasing system size the exact solution of the open quantum system dynamics requires memory and compute resources beyond a single compute node. To overcome this barrier, we developed a scalable variant of HEOM. Our distributed memory HEOM, DM-HEOM, is a universal tool for open quantum system dynamics. It is used to accurately compute all experimentally accessible time- and frequency resolved processes in light harvesting molecular complexes with arbitrary system-environment couplings for a wide range of temperatures and complex sizes.

1201.1071

Absolute regularity and ergodicity of Poisson count processes

We consider a class of observation-driven Poisson count processes where the current value of the accompanying intensity process depends on previous values of both processes. We show under a contractive condition that the bivariate process has a unique stationary distribution and that a stationary version of the count process is absolutely regular. Moreover, since the intensities can be written as measurable functionals of the count variables, we conclude that the bivariate process is ergodic. As an important application of these results, we show how a test method previously used in the case of independent Poisson data can be used in the case of Poisson count processes.

1712.08474

Relation between Raman backscattering from droplets and bulk water: Effect of refractive index dispersion

A theoretical framework is presented that permits investigations of the relation between inelastic backscattering from microparticles and bulk samples of Raman-active materials. It is based on the Lorentz reciprocity theorem and no fundamental restrictions concerning the microparticle shape apply. The approach provides a simple and intuitive explanation for the enhancement of the differential backscattering cross-section in particles in comparison to bulk. The enhancement factor for scattering of water droplets in the diameter range from 0 to 60\,\textmu m (vitally important for the \emph{a priori} measurement of liquid water content of warm clouds with spectroscopic Raman lidars) is about a factor of 1.2-1.6 larger (depending on the size of the sphere) than an earlier study has shown. The numerical calculations are extended to 1000\,\textmu m and demonstrate that dispersion of the refractive index of water becomes an important factor for spheres larger than 100 \textmu m. The physics of the oscillatory phenomena predicted by the simulations is explained.

2009.05033

5G meets Construction Machines: Towards a Smart working Site

The fleet management of mobile working machines with the help of connectivity can increase safety and productivity. Although in our previous study, we proposed a solution to use IEEE 802.11p to achieve the fleet management of construction machines, the shortcoming of WIFI may limit the usage of this technology in some cases. Alternatively, the fifth-generation mobile networks (5G) have shown great potential to solve the problems. Thus, as the world's first academic paper investigating 5G and construction machines' cooperation, we demonstrated the scenarios where 5G can have a significant effect on the construction machines industry. Also, based on the simulation we made in $ns-3$, we compared the performance of 4G and 5G for the most relevant construction machines scenarios. Last but not least, we showed the feasibility of remote-control and self-working construction machines with the help of 5G.

0804.0898

V2051 Oph after superoutburst: out-of-plane material and the superhump light source

We performed a detailed spectroscopic analysis of the dwarf nova V2051 Oph at the end of its 1999 superoutburst. We studied and interpreted the simultaneous behaviour of various emission lines. We obtained high-resolution echelle spectroscopic data at ESO's NTT with EMMI, covering the spectral range of 4000--7500 Angstrom. The analysis was performed using standard IRAF tools. The indirect imaging technique of Doppler tomography was applied, in order to map the accretion disc and distinguish between the different emission sources. The spectra are characterised by strong Balmer emission, together with lines of HeI and the iron triplet FeII 42. All lines are double-peaked, but the blue-to-red peak strength and central absorption depth vary. The primary's velocity was found to be 84.9 km/sec. The spectrograms of the emission lines reveal the prograde rotation of a disc-like emitting region and, for the Balmer and HeI lines, an enhancement of the red-wing during eclipse indicates a bright spot origin. The modulation of the double-peak separation shows a highly asymmetric disc with non-uniform emissivity. This is confirmed by the Doppler maps, which apart from the disc and bright spot emission also indicate an additional region of enhanced emission in the 4th quadrant (+Vx, -Vy), which we associate with the superhump light source. Given the behaviour of the iron triplet and its distinct differences from the rest of the lines, we attribute its existence to an extended gas region above the disc. Its origin can be explained through the fluorescence mechanism.

1712.09560

Geometric structures and Lie algebroids

In this thesis we study geometric structures from Poisson and generalized complex geometry with mild singular behavior using Lie algebroids. The process of lifting such structures to their Lie algebroid version makes them less singular, as their singular behavior is incorporated in the anchor of the Lie algebroid. We develop a framework for this using the concept of a divisor, which encodes the singularities, and show when structures exhibiting such singularities can be lifted to a Lie algebroid built out of the divisor. Once one has successfully lifted the structure, it becomes possible to study it using more powerful techniques. In the case of Poisson structures one can turn to employing symplectic techniques. These lead for example to normal form results for the underlying Poisson structures around their singular loci. In this thesis we further adapt the methods of Gompf and Thurston for constructing symplectic structures out of fibration-like maps to their Lie algebroid counterparts. More precisely, we introduce the notion of a Lie algebroid Lefschetz fibration and show when these give rise to A-symplectic structures for a given Lie algebroid A. We then use this general result to show how log-symplectic structures arise out of achiral Lefschetz fibrations. Moreover, we introduce the concept of a boundary Lefschetz fibration and show when they allow their total space to be equipped with a stable generalized complex structure. Other results in this thesis include homotopical obstructions to the existence of A-symplectic structures using characteristic classes, and splitting results for A-Lie algebroids (i.e., Lie algebroids whose anchor factors through that of a fixed Lie algebroid A), around specific transversal submanifolds.

2001.02408

Disentangling Multiple Features in Video Sequences using Gaussian Processes in Variational Autoencoders

We introduce MGP-VAE (Multi-disentangled-features Gaussian Processes Variational AutoEncoder), a variational autoencoder which uses Gaussian processes (GP) to model the latent space for the unsupervised learning of disentangled representations in video sequences. We improve upon previous work by establishing a framework by which multiple features, static or dynamic, can be disentangled. Specifically we use fractional Brownian motions (fBM) and Brownian bridges (BB) to enforce an inter-frame correlation structure in each independent channel, and show that varying this structure enables one to capture different factors of variation in the data. We demonstrate the quality of our representations with experiments on three publicly available datasets, and also quantify the improvement using a video prediction task. Moreover, we introduce a novel geodesic loss function which takes into account the curvature of the data manifold to improve learning. Our experiments show that the combination of the improved representations with the novel loss function enable MGP-VAE to outperform the baselines in video prediction.

cs/0008003

Interfacing Constraint-Based Grammars and Generation Algorithms

Constraint-based grammars can, in principle, serve as the major linguistic knowledge source for both parsing and generation. Surface generation starts from input semantics representations that may vary across grammars. For many declarative grammars, the concept of derivation implicitly built in is that of parsing. They may thus not be interpretable by a generation algorithm. We show that linguistically plausible semantic analyses can cause severe problems for semantic-head-driven approaches for generation (SHDG). We use SeReal, a variant of SHDG and the DISCO grammar of German as our source of examples. We propose a new, general approach that explicitly accounts for the interface between the grammar and the generation algorithm by adding a control-oriented layer to the linguistic knowledge base that reorganizes the semantics in a way suitable for generation.

0801.0781

Magnetic domain wall propagation in a submicron spin-valve stripe: influence of the pinned layer

The propagation of a domain wall in a submicron ferromagnetic spin-valve stripe is investigated using giant magnetoresistance. A notch in the stripe efficiently traps an injected wall stopping the domain propagation. The authors show that the magnetic field at which the wall is depinned displays a stochastic nature. Moreover, the depinning statistics are significantly different for head to head and tail-to-tail domain walls. This is attributed to the dipolar field generated in the vicinity of the notch by the pinned layer of the spin-valve.

gr-qc/0312041

On the viability of the Palatini form of 1/R gravity

Recently Flanagan [astro-ph/0308111] has argued that the Palatini form of 1/R gravity is ruled out by experiments such as electron-electron scattering. His argument involves adding minimally coupled fermions in the Jordan frame and transforming to the Einstein frame. This produces additional terms that are ruled out experimentally. Here I argue that this conclusion is false. It is well known that conformally related theories are mathematically equivalent but not physically equivalent. As discussed by Magnano and Sokolowski [2] one must decide, in the vacuum theory, which frame is the physical frame and add the minimally coupled Lagrangian in this frame. If this procedure is followed the resulting theory is not ruled out experimentally. The discussions in this paper also show that the equivalence between the generalized gravitational theories and scalar tensor theories discussed by Flanagan [gr-qc/0309015] is only mathematical, not physical.

1407.4279

Sub-meV linewidth in GaN nanowire ensembles: absence of surface excitons due to the field-ionization of donors

We observe unusually narrow donor-bound exciton transitions (0.4 meV) in the photoluminescence spectra of GaN nanowire ensembles grown on Si(111) substrates at very high (> 850 degrees Celsius) temperatures. The spectra of these samples reveal a prominent transition of excitons bound to neutral Si impurities which is not observed for samples grown under standard conditions. Motivated by these experimental results, we investigate theoretically the impact of surface-induced internal electric fields on the binding energy of donors by a combined Monte Carlo and envelope function approach. We obtain the ranges of doping and diameter for which the potential is well described using the Poisson equation, where one assumes a spatially homogeneous distribution of dopants. Our calculations also show that surface donors in nanowires with a diameter smaller than 100 nm are ionized when the surface electric field is larger than about 10 kV/cm, corresponding to a doping level higher than 2 x 10^16 cm^-3. This result explains the experimental observation: since the (D+,X) complex is not stable in GaN, surface-donor-bound excitons do not contribute to the photoluminescence spectra of GaN nanowires above a certain doping level, and the linewidth reflects the actual structural perfection of the nanowire ensemble.

1312.7440

Photo-Disintegration of Heavy Nuclei at the Core of Cen A

Fermi LAT has detected gamma ray emissions from the core of Cen A. More recently, a new component in the gamma ray spectrum from the core has been reported in the energy range of 4 GeV to tens of GeV. We show that the new component and the HESS detected spectrum of gamma rays from the core at higher energy have possibly a common origin in photo-disintegration of heavy nuclei. Assuming the cosmic rays are mostly Fe nuclei inside the core and their spectrum has a low energy cut-off at 52 TeV in the wind frame moving with a Doppler factor 0.25 with respect to the observer on earth, the cosmic ray luminosity required to explain the observed gamma ray flux above 1 GeV is found to be $1.5\times 10^{43}$ erg/sec.

cond-mat/0005360

Controlling the Size of Popcorn

We present a thermo-statistical model of popcorn production and propose a way to control the final size of the popcorn by monitoring only the chamber pressure.

0907.2869

Large U_{e3} and Tri-bimaximal Mixing

We investigate in a model-independent way to what extent one can perturb tri-bimaximal mixing in order to generate a sizable value of |U_{e3}|, while at the same time keeping solar neutrino mixing near its measured value, which is close to sin^2 theta_{12} = 1/3. Three straightforward breaking mechanisms to generate |U_{e3}| of about 0.1 are considered. For charged lepton corrections, the suppression of a sizable contribution to sin^2 theta_{12} can be achieved if CP violation in neutrino oscillations is almost maximal. Generation of the indicated value of |U_{e3}| of about 0.1 through renormalization group corrections requires the neutrinos to be quasi-degenerate in mass. The consistency with the allowed range of sin^2 theta_{12} together with large running of |U_{e3}| forces one of the Majorana phases to be close to pi. This implies large cancellations in the effective Majorana mass governing neutrino-less double beta, constraining it to lie near its minimum allowed value of m_0 cos 2 theta_{12}, where m_0 is greater than about 0.1 eV. Finally, explicit breaking of the neutrino mass matrix in the inverted hierarchical and quasi-degenerate neutrino mass spectrum cases is similarly correlated with the effective Majorana mass, although to a lesser extent. The implied values for the atmospheric neutrino mixing angle theta_{23} are given in all cases.

hep-ph/9512420

Nobel Leptons

The 1995 Nobel Prize in Physics is shared equally by the American physicists Frederick J. Reines and Martin L. Perl for their pioneering experimental contributions to lepton physics. Following is a brief account of their discoveries.

1704.03873

Architectural Challenges and Solutions for Collocated LWIP - A Network Layer Perspective

Achieving a tighter level of aggregation between LTE and Wi-Fi networks at the radio access network (a.k.a. LTE-Wi-Fi Aggregation or LWA) has become one of the most prominent solutions in the era of 5G to boost network capacity and improve end user's quality of experience. LWA offers flexible resource scheduling decisions for steering user traffic via LTE and Wi-Fi links. In this work, we propose a Collocated LTE/WLAN Radio Level Integration architecture at IP layer (C-LWIP), an enhancement over 3GPP non-collocated LWIP architecture. We have evaluated C-LWIP performance in various link aggregation strategies (LASs). A C-LWIP node (i.e., the node having collocated, aggregated LTE eNodeB and Wi-Fi access point functionalities) is implemented in NS-3 which introduces a traffic steering layer (i.e., Link Aggregation Layer) for efficient integration of LTE and Wi-Fi. Using extensive simulations, we verified the correctness of C-LWIP module in NS-3 and evaluated the aggregation benefits over standalone LTE and Wi-Fi networks with respect to varying number of users and traffic types. We found that split bearer performs equivalently to switched bearer for UDP flows and switched bearer outperforms split bearer in the case of TCP flows. Also, we have enumerated the potential challenges to be addressed for unleashing C-LWIP capabilities. Our findings also include WoD-Link Aggregation Strategy which is shown to improve system throughput by 50% as compared to Naive-LAS in a densely populated indoor stadium environment.

cond-mat/9801131

A Systematic Improvement for Calculation to Conductivity in Anomalous Propagation of Surface Acoustic Wave at $\nu={1/2}$

We report a systematic improvement to calculate the conductivity which associates to the anomaly of the propagation of surface acoustic waves at $\nu={1/2}$ above a two-dimensional electron gas. We try to resolve the discrepancy between theoretical and experimental values for the magnitude of $\sigma_{xx}(q)$ by considering the contribution to the response functions from the self-interaction among the Chern-Simons gauge fluctuations.

0805.4502

Golden Space-Time Block Coded Modulation

In this paper we present a block coded modulation scheme for a 2 x 2 MIMO system over slow fading channels, where the inner code is the Golden Code. The scheme is based on a set partitioning of the Golden Code using two-sided ideals whose norm is a power of two. In this case, a lower bound for the minimum determinant is given by the minimum Hamming distance. The description of the ring structure of the quotients suggests further optimization in order to improve the overall distribution of determinants. Performance simulations show that the GC-RS schemes achieve a significant gain over the uncoded Golden Code.

2306.00391

Extremal Peisert-type graphs without the strict-EKR property

It is known that Paley graphs of square order have the strict-EKR property. Peisert-type graphs are natural generalizations of Paley graphs and some of them also have the strict-EKR property. Given a prime power $q$, we study extremal Peisert-type graphs of order $q^2$ without the strict-EKR property, that is, Peisert-type graphs of order $q^2$ without the strict-EKR property and with the minimum number of edges. First, we determine this minimum number of edges for each value of $q$. If $q$ is a square, we show the uniqueness of the extremal graph and its isomorphism with certain affine polar graph. Using the isomorphism, we conclude that there is no Hilton-Milner type result for this extremal graph. We also prove the tightness of the weight-distribution bound for both non-principal eigenvalues of this graph. If $q$ is a cube but not a square, we show the uniqueness of the extremal graph and determine the number and the structure of non-canonical cliques. Finally, we show such uniqueness result does not extend to all $q$.

2112.13285

Pedagogical Rule Extraction to Learn Interpretable Models - an Empirical Study

Machine-learning models are ubiquitous. In some domains, for instance, in medicine, the models' predictions must be interpretable. Decision trees, classification rules, and subgroup discovery are three broad categories of supervised machine-learning models presenting knowledge in the form of interpretable rules. The accuracy of these models learned from small datasets is usually low. Obtaining larger datasets is often hard to impossible. Pedagogical rule extraction methods could help to learn better rules from small data by augmenting a dataset employing statistical models and using it to learn a rule-based model. However, existing evaluation of these methods is often inconclusive, and they were not compared so far. Our framework PRELIM unifies existing pedagogical rule extraction techniques. In the extensive experiments, we identified promising PRELIM configurations not studied before.

1808.07195

Circumnuclear Multi-phase Gas in Circinus Galaxy III: Structure of the Nuclear Ionized Gas

We investigate the properties of the ionized gas irradiated by an active galactic nucleus (AGN) based on our "radiation-driven fountain" model for the nearest type-2 Seyfert galaxy, the Circinus galaxy (Wada et al. 2016). We conducted "quasi-three dimensional" spectral analysis using the spectral synthesis code CLOUDY and obtained the surface brightness distributions of lines, such as H$\alpha$, H$\beta$, [OIII], [NII], and [SII] for the central 16-parsec region. The ionized regions observed based on these lines show a conical morphology around the rotation axis, even if we do not phenomenologically postulate the presence of an optically thick "torus". This region also shows non-uniform internal structures, reflecting the inhomogeneous structure of fountain flows. Using ionization diagnostic diagrams, we investigated the spectral properties of the ionized gas. The diagrams based on the line ratios of [NII]/H$\alpha$ and [SII]/H$\alpha$ show that most regions of the cone have the same properties as those in the narrow line regions (NLRs) in AGNs, whereas using [OI]/H$\alpha$, the central 10-pc regions are rather LINER-like. The gas density, temperature, and ionizing parameter in regions identified as "NLR" are typically $n \sim 300-1500$ cm$^{-3}$, $T \sim 1-3 \times 10^4 $ K, and $ U \sim 0.01$, respectively. The morphology and [OIII] intensity are similar to the base of the observed [OIII] cone in the Circinus galaxy, implying some physical connections with the origin of the $\sim100$ parsec scale NLR.

1807.02204

Neutrino masses, cosmological inflation and dark matter in a $U(1)_{B-L}$ model with type II seesaw mechanism

In this work we implement the type II seesaw mechanism into the framework of the $U(1)_{B-L}$ gauge model. As main gain, the right-handed neutrinos of the model get free to play the role of the dark matter of the universe. As side effect, the model realizes Higgs inflation without problem with loss of unitarity.

1310.7774

Ghost: A Uniform and General-Purpose Proxy Implementation

A proxy object is a surrogate or placeholder that controls access to another target object. Proxy objects are a widely used solution for different scenarios such as remote method invocation, future objects, behavioral reflection, object databases, inter-languages communications and bindings, access control, lazy or parallel evaluation, security, among others. Most proxy implementations support proxies for regular objects but are unable to create proxies for objects with an important role in the runtime infrastructure such as classes or methods. Proxies can be complex to install, they can have a significant overhead, they can be limited to certain kind of classes, etc. Moreover, proxy implementations are often not stratified and they do not have a clear separation between proxies (the objects intercepting messages) and handlers (the objects handling interceptions). In this paper, we present Ghost: a uniform and general-purpose proxy implementation for the Pharo programming language. Ghost provides low memory consuming proxies for regular objects as well as for classes and methods. When a proxy takes the place of a class, it intercepts both the messages received by the class and the lookup of methods for messages received by its instances. Similarly, if a proxy takes the place of a method, then the method execution is intercepted too.

2303.06767

A note on Hutchinson operator in $\mathbf{T_1}$ compact topological spaces

In $T_1$ compact topological spaces the Hutchinson operator of a contractive IFS (iterated function system; a finite family of closed mappings from the space into itself) may not be closed. Nevertheless, the Hutchinson operator of a contractive IFS has always a unique fixed point.

1607.02034

Low temperature Hall effect in bismuth chalcogenides thin films

Bismuth chalcogenides are the most studied 3D topological insulators. As a rule, at low temperatures thin films of these materials demonstrate positive magnetoresistance due to weak antilocalization. Weak antilocalization should lead to resistivity decrease at low temperatures; in experiments, however, resistivity grows as temperature decreases. From transport measurements for several thin films (with various carrier density, thickness, and carrier mobility), and by using purely phenomenological approach, with no microscopic theory, we show that the low temperature growth of the resistivity is accompanied by growth of the Hall coefficient, in agreement with diffusive electron-electron interaction correction mechanism. Our data reasonably explain the low-temperature resistivity upturn.

1505.04839

Revisiting the Rigidly Rotating Magnetosphere model for $\sigma$ Ori E - II. Magnetic Doppler imaging, arbitrary field RRM, and light variability

The initial success of the Rigidly Rotating Magnetosphere (RRM) model application to the B2Vp star sigma OriE by Townsend, Owocki & Groote (2005) triggered a renewed era of observational monitoring of this archetypal object. We utilize high-resolution spectropolarimetry and the magnetic Doppler imaging (MDI) technique to simultaneously determine the magnetic configuration, which is predominately dipolar, with a polar strength Bd = 7.3-7.8 kG and a smaller non-axisymmetric quadrupolar contribution, as well as the surface distribution of abundance of He, Fe, C, and Si. We describe a revised RRM model that now accepts an arbitrary surface magnetic field configuration, with the field topology from the MDI models used as input. The resulting synthetic Ha emission and broadband photometric observations generally agree with observations, however, several features are poorly fit. To explore the possibility of a photospheric contribution to the observed photometric variability, the MDI abundance maps were used to compute a synthetic photospheric light curve to determine the effect of the surface inhomogeneities. Including the computed photospheric brightness modulation fails to improve the agreement between the observed and computed photometry. We conclude that the discrepancies cannot be explained as an effect of inhomogeneous surface abundance. Analysis of the UV light variability shows good agreement between observed variability and computed light curves, supporting the accuracy of the photospheric light variation calculation. We thus conclude that significant additional physics is necessary for the RRM model to acceptably reproduce observations of not only sigma Ori E, but also other similar stars with significant stellar wind-magnetic field interactions.

2210.06535

Development of a Simulation Environment for Evaluation of a Forward Looking Sonar System for Small AUVs

This paper describes a high-fidelity sonar model and a simulation environment that implements the model. The model and simulation environment have been developed to aid in the design of a forward looking sonar for autonomous underwater vehicles (AUVs). The simulator achieves real-time visualization through ray tracing and approximation. The simulator facilitates the assessment of sonar design choices, such as beam pattern and beam location, and assessment of obstacle detection and tracking algorithms. An obstacle detection model is proposed for which the null hypothesis is estimated from the environmental model. Sonar data is generated from the simulator and compared to the expected results from the detection model demonstrating the benefits and limitations of the proposed approach.

cs/0402017

Alchemi: A .NET-based Grid Computing Framework and its Integration into Global Grids

Computational grids that couple geographically distributed resources are becoming the de-facto computing platform for solving large-scale problems in science, engineering, and commerce. Software to enable grid computing has been primarily written for Unix-class operating systems, thus severely limiting the ability to effectively utilize the computing resources of the vast majority of desktop computers i.e. those running variants of the Microsoft Windows operating system. Addressing Windows-based grid computing is particularly important from the software industry's viewpoint where interest in grids is emerging rapidly. Microsoft's .NET Framework has become near-ubiquitous for implementing commercial distributed systems for Windows-based platforms, positioning it as the ideal platform for grid computing in this context. In this paper we present Alchemi, a .NET-based grid computing framework that provides the runtime machinery and programming environment required to construct desktop grids and develop grid applications. It allows flexible application composition by supporting an object-oriented grid application programming model in addition to a grid job model. Cross-platform support is provided via a web services interface and a flexible execution model supports dedicated and non-dedicated (voluntary) execution by grid nodes.

2311.12086

Masked Autoencoders Are Robust Neural Architecture Search Learners

Neural Architecture Search (NAS) currently relies heavily on labeled data, which is both expensive and time-consuming to acquire. In this paper, we propose a novel NAS framework based on Masked Autoencoders (MAE) that eliminates the need for labeled data during the search process. By replacing the supervised learning objective with an image reconstruction task, our approach enables the robust discovery of network architectures without compromising performance and generalization ability. Additionally, we address the problem of performance collapse encountered in the widely-used Differentiable Architecture Search (DARTS) method in the unsupervised paradigm by introducing a multi-scale decoder. Through extensive experiments conducted on various search spaces and datasets, we demonstrate the effectiveness and robustness of the proposed method, providing empirical evidence of its superiority over baseline approaches.

0711.3862

Supersymmetric QFT, Super Loop Spaces and Bismut-Chern Character

In this paper, we give a quantum interpretation of the Bismut-Chern character form (the loop space lifting of the Chern character form) as well as the Chern character form associated to a complex vector bundle with connection over a smooth manifold in the framework of supersymmetric quantum field theories developed by Stolz and Teichner \cite{ST07}. We show that the Bismut-Chern character form comes up via a loop-deloop process when one goes from $1|1$D theory over a manifold down to a $0|1$D theory over its free loop space. Based on our quantum interpretation of the Bismut-Chern character form and Chern character form, we construct Chern character type maps for SUSY QFTs.

1303.2490

Certified quantum non-demolition measurement of a macroscopic material system

Quantum non-demolition (QND) measurements improve sensitivity by evading measurement back-action. The technique was first proposed to detect mechanical oscillations in gravity wave detectors,and demonstrated in the measurement of optical fields, leading to the development of rigorous criteria to distinguish QND from similar non-classical measurements. Recent QND measurements of macroscopic material systems such as atomic ensembles, and mechanical oscillators, show some QND features, but not full QND character. Here we demonstrate certified QND measurement of the collective spin of an atomic ensemble. We observe quantum state preparation (QSP) and information-damage trade-off (IDT) beyond their classical limits by seven and twelve standard deviations, respectively. Our techniques complement recent work with microscopic systems, and can be used for quantum metrology and memory, the preparation and detection of non-gaussian states, and proposed quantum simulation and information protocols. They should enable QND measurements of dynamical quantum variables and the realization of QND-based quantum information protocols.

1707.08217

Direct Numerical Simulation of Turbulent Channel Flow with Riblets at Low Reynolds Number

In this report we briefly summarize the set-up and results for direct numerical simulations (DNS) of turbulent channel flows with riblets. The DNS are carried out with OpenFOAM which allows the use of an unstructured mesh. The present results were presented at the European Drag Reduction and Flow Control Meeting in 2015.

2206.04545

Novel resolution analysis for the Radon transform in $\mathbb R^2$ for functions with rough edges

Let $f$ be a function in $\mathbb R^2$, which has a jump across a smooth curve $\mathcal S$ with nonzero curvature. We consider a family of functions $f_\epsilon$ with jumps across a family of curves $\mathcal S_\epsilon$. Each $\mathcal S_\epsilon$ is an $O(\epsilon)$-size perturbation of $\mathcal S$, which scales like $O(\epsilon^{-1/2})$ along $\mathcal S$. Let $f_\epsilon^{\text{rec}}$ be the reconstruction of $f_\epsilon$ from its discrete Radon transform data, where $\epsilon$ is the data sampling rate. A simple asymptotic (as $\epsilon\to0$) formula to approximate $f_\epsilon^{\text{rec}}$ in any $O(\epsilon)$-size neighborhood of $\mathcal S$ was derived heuristically in an earlier paper of the author. Numerical experiments revealed that the formula is highly accurate even for nonsmooth (i.e., only H{\"o}lder continuous) $\mathcal S_\epsilon$. In this paper we provide a full proof of this result, which says that the magnitude of the error between $f_\epsilon^{\text{rec}}$ and its approximation is $O(\epsilon^{1/2}\ln(1/\epsilon))$. The main assumption is that the level sets of the function $H_0(\cdot,\epsilon)$, which parametrizes the perturbation $\mathcal S\to\mathcal S_\epsilon$, are not too dense.

0901.0971

The mathematics of Donald Gordon Higman

This is about the mathematics and life of Donald Gordon Higman, 1928-2006. He did important work in representation theory of groups and algebras and in algebraic combinatorics. Charles C. Sims and Donald Higman discovered and constructed one of the sporadic simple groups.

2106.13855

Unbinned Angular Analysis of $B\to D^*\ell \nu_\ell$ and the Right-handed Current

In this article, we perform a sensitivity study of an unbinned angular analysis of the $B\to D^*\ell \nu_\ell$ decay, including the contributions from the right-handed current. We show that the angular observable can constrain very strongly the right-handed current without the intervention of the yet unsolved $V_{cb}$ puzzle.

1109.3235

A new spin on quantum cryptography: Avoiding trapdoors and embracing public keys

We give new arguments in support of \emph{signed quantum key establishment}, where quantum cryptography is used in a public-key infrastructure that provides the required authentication. We also analyze more thoroughly than previous works the benefits that quantum key establishment protocols have over certain classical protocols, motivated in part by the various objections to quantum key establishment that are sometimes raised. Previous knowledge of quantum cryptography on the reader's part is not required for this article, as the definition of "quantum key establishment" that we use is an entirely classical and black-box characterization (one need only trust that protocols satisfying the definition exist).

1307.1583

The network of stabilizing contacts in proteins studied by coevolutionary data

The primary structure of proteins, that is their sequence, represents one of the most abundant set of experimental data concerning biomolecules. The study of correlations in families of co--evolving proteins by means of an inverse Ising--model approach allows to obtain information on their native conformation. Following up on a recent development along this line, we optimize the algorithm to calculate effective energies between the residues, validating the approach both back-calculating interaction energies in a model system, and predicting the free energies associated to mutations in real systems. Making use of these effective energies, we study the networks of interactions which stabilizes the native conformation of some well--studied proteins, showing that it display different properties than the associated contact network.

nucl-th/0607048

Connecting the X(5)-$\beta^2$, X(5)-$\beta^4$, and X(3) models to the shape/phase transition region of the interacting boson model

The parameter independent (up to overall scale factors) predictions of the X(5)-$\beta^2$, X(5)-$\beta^4$, and X(3) models, which are variants of the X(5) critical point symmetry developed within the framework of the geometric collective model, are compared to two-parameter calculations in the framework of the interacting boson approximation (IBA) model. The results show that these geometric models coincide with IBA parameters consistent with the phase/shape transition region of the IBA for boson numbers of physical interest (close to 10). Nuclei within the rare-earth region and select Os and Pt isotopes are identified as good examples of X(3), X(5)-$\beta^2$, and X(5)-$\beta^4$ behavior.

astro-ph/0612181

Fine structure in the gamma-ray sky and the origin of UHECR

The EGRET results for gamma ray intensities in and near the Galactic Plane have been analysed in some detail. Attention has been concentrated on energies above 1 GeV and the individual intensities in a $4^{\circ}$ longitude bin have been determined and compared with the large scale mean found from a nine-degree polynomial fit. Comparison has been made of the observed standard deviation for the ratio of these intensities with that expected from variants of our model. The basic model adopts cosmic ray origin from supernova remnants, the particles then diffusing through the Galaxy with our usual `anomalous diffusion'. The variants involve the clustering of SN, a frequency distribution for supernova explosion energies, and 'normal', rather than 'anomalous' diffusion. It is found that for supernovae of unique energy, and our usual anomalous diffusion, clustering is necessary, particularly in the Inner Galaxy. An alternative, and preferred, situation is to adopt the model with a frequency distribution of supernova energies. The results for the Outer Galaxy are such that no clustering is required. If their explosion energies are distributed then supernovae can be the origin of UHECR.