September 2019 arXiv papers — page 54

Tommaso Menara, Giacomo Baggio, Danielle S. Bassett, Fabio Pasqualetti

In this paper, we propose a framework to control brain-wide functional connectivity by selectively acting on the brain's structure and parameters. Functional connectivity, which measures the degree of correlation between neural activities in different brain regions, can be used to distinguish between healthy and certain diseased brain dynamics and, possi

Usman A. Fiaz, John S. Baras

This paper investigates a hybrid compositional approach to optimal mission planning for multi-rotor Unmanned Aerial Vehicles (UAVs). We consider a time critical search and rescue scenario with two quadrotors in a constrained environment. Metric Temporal Logic (MTL) is used to formally describe the task specifications. In order to capture the various modes of

Harish Doddi, Saurav Talukdar, Deepjyoti Deka, Murti Salapaka

Learning the structure of a network from time series data, in particular cyclostationary data, is of significant interest in many disciplines such as power grids, biology and finance. In this article, an algorithm is presented for reconstruction of the topology of a network of cyclostationary processes. To the best of our knowledge, this is the first work to

Sebastian Curi, Kfir Y. Levy, Andreas Krause

We address the problem of estimating the inputs of a dynamical system from measurements of the system's outputs. To this end, we introduce a novel estimation algorithm that explicitly trades off bias and variance to optimally reduce the overall estimation error. This optimal trade-off is done efficiently and adaptively in every time step. Experimentally,

Olaoluwapo Ajala, Alejandro Dominguez-garcia, Peter Sauer, Daniel Liberzon

This paper presents a library of second-order models for synchronous machines that can be utilized in power system dynamic performance analysis and control design tasks. The models have a similar structure to the classical model in that they consist of two dynamic states, the power angle and the angular speed. However, unlike the classical model, the models

Grace H. Zhang, David R. Nelson

Complex networks with directed, local interactions are ubiquitous in nature, and often occur with probabilistic connections due to both intrinsic stochasticity and disordered environments. Sparse non-Hermitian random matrices arise naturally in this context, and are key to describing statistical properties of the non-equilibrium dynamics that emerges from in

Philipe de Freitas Melo, Carolina Coimbra Vieira, Kiran Garimella, Pedro O. S. Vaz de Melo

WhatsApp is the most popular messaging app in the world. The closed nature of the app, in addition to the ease of transferring multimedia and sharing information to large-scale groups make WhatsApp unique among other platforms, where an anonymous encrypted messages can become viral, reaching multiple users in a short period of time. The personal feeling and

Koki Hirota, Jens Wittsten

We analyze the eigenvalue problem for the semiclassical Dirac (or Zakharov-Shabat) operator on the real line with general analytic potential. We provide Bohr-Sommerfeld quantization conditions near energy levels where the potential exhibits the characteristics of a single or double bump function. From these conditions we infer that near energy levels where t

Nan Wang, Hongning Wang

Multi-aspect user preferences are attracting wider attention in recommender systems, as they enable more detailed understanding of users' evaluations of items. Previous studies show that incorporating multi-aspect preferences can greatly improve the performance and explainability of recommendation. However, as recommendation is essentially a ranking problem,

Macheng Shen, Jonathan P. How

This paper presents an algorithmic framework for learning robust policies in asymmetric imperfect-information games, where the joint reward could depend on the uncertain opponent type (a private information known only to the opponent itself and its ally). In order to maximize the reward, the protagonist agent has to infer the opponent type through agent mode

Ian May, Ronald Haynes, Steven Ruuth

The discretization of surface intrinsic elliptic partial differential equations (PDEs) poses interesting challenges not seen in flat space. The discretization of these PDEs typically proceeds by either parametrizing the surface, triangulating the surface, or embedding the surface in a higher dimensional flat space. The closest point method (CPM) is an embedd

Nabarun Deb, Bodhisattva Sen

In this paper, we propose a general framework for distribution-free nonparametric testing in multi-dimensions, based on a notion of multivariate ranks defined using the theory of measure transportation. Unlike other existing proposals in the literature, these multivariate ranks share a number of useful properties with the usual one-dimensional ranks; most im

S. Kravitz, R. J. Smith, L. Hagaman, E. P. Bernard

Liquid xenon particle detectors rely on excellent light collection efficiency for their performance. This depends on the high reflectivity of polytetrafluoroethylene (PTFE) at the xenon scintillation wavelength of 178 nm, but the angular dependence of this reflectivity is not well-understood. IBEX is designed to directly measure the angular distribution of x

Han Wang, Shangyu Xie, Yuan Hong

Massive amounts of video data are ubiquitously generated in personal devices and dedicated video recording facilities. Analyzing such data would be extremely beneficial in real world (e.g., urban traffic analysis, pedestrian behavior analysis, video surveillance). However, videos contain considerable sensitive information, such as human faces, identities and

Isaiah Morgenstern, Shan Zhong, Qimin Zhang, Logan Baker

We present a microwave source that is controlled by a commercially available field programmable gate array (FPGA). Using an FPGA allows for precise control of the time dependent microwave-dressing applied to a sample of trapped cold atoms. We test our microwave source by exciting Rabi oscillations in a Na spinor Bose-Einstein Condensate. We include, as suppl

S. Loyka, M. Khojastehnia

It is shown that the condition of Theorem 1 in [1] never holds in practice and that Theorem 2 is incorrect under the stated condition. Extra assumptions or/and modifications are needed to make the conclusions of Theorem 1 and 2 above valid, which are provided below.

Yiming Wang, Tongfei Chen, Hainan Xu, Shuoyang Ding

We present Espresso, an open-source, modular, extensible end-to-end neural automatic speech recognition (ASR) toolkit based on the deep learning library PyTorch and the popular neural machine translation toolkit fairseq. Espresso supports distributed training across GPUs and computing nodes, and features various decoding approaches commonly employed in ASR,

Li Chen, Xin Li, Peter Pickl, Qitao Yin

In this paper we consider the mean field limit and non-relativistic limit of relativistic Vlasov-Maxwell particle system to Vlasov-Poisson equation. With the relativistic Vlasov-Maxwell particle system being a starting point, we carry out the estimates (with respect to $N$ and $c$) between the characteristic equation of both Vlasov-Maxwell particle model and

Romit Maulik, Vishwas Rao, Sandeep Madireddy, Bethany Lusch

Rapid simulations of advection-dominated problems are vital for multiple engineering and geophysical applications. In this paper, we present a long short-term memory neural network to approximate the nonlinear component of the reduced-order model (ROM) of an advection-dominated partial differential equation. This is motivated by the fact that the nonlinear t

Joshua Frisch, Forte Shinko

We show that for any Polish group $G$ and any countable normal subgroup $\Gamma\triangleleft G$, the coset equivalence relation $G/\Gamma$ is a hyperfinite Borel equivalence relation. In particular, the outer automorphism group of any countable group is hyperfinite.

Xinlun Cheng

Strong lensing is one of the most spectacular views in the universe. Many cosmological applications have been proposed, but the number of such lensing systems is still limited. In this work, we applied an improved version of a previously developed spectroscopic lensing search method to the SDSS-III BOSS and proposed a list of highly possible candidates. Foll

Hami Rabbani, Gabriele Liga, Vinicius Oliari, Lotfollah Beygi

Ultra-wideband fiber optical transmission suffers from both Kerr nonlinearity and stimulated Raman scattering (SRS). Mathematical models that address the interplay between Kerr nonlinearity and SRS exist. These models are based on the Gaussian-noise (GN) and enhanced Gaussian noise (EGN) models. In this paper, we propose a modulation-format-dependent model,

Andrea Braides, Andrey Piatnitski

We prove a homogenization theorem for quadratic convolution energies defined in perforated domains. The corresponding limit is a Dirichlet-type quadratic energy, whose integrand is defined by a non-local cell-problem formula. The proof relies on an extension theorem from perforated domains belonging to a wide class containing compact periodic perforations.

Jianguo Zhang, Dapeng Zhou

In this paper, we verify the $L^p$ coarse Baum-Connes conjecture for spaces with finite asymptotic dimension for $p\in[1,\infty)$. We also show that the $K$-theory of $L^p$ Roe algebras are independent of $p\in(1,\infty)$ for spaces with finite asymptotic dimension.

Lucas Backes, Davor Dragicevic

We prove that small nonlinear perturbations of random linear dynamics admitting a tempered exponential dichotomy have a random version of the shadowing property. As a consequence, if the exponential dichotomy is uniform, we get that the random linear dynamics is Hyers-Ulam stable. Moreover, we apply our results to study the conservation of Lyapunov exponents

Georgia T. Papadakis, Siddharth Buddhiraju, Zhexin Zhao, Bo Zhao

The conventional notion for achieving high efficiency in thermophotovoltaics (TPVs) is to use a monochromatic emission at a photon energy corresponding to the band gap of the cell. Here, we prove theoretically that such a notion is only accurate under idealized conditions, and further show that when non-radiative recombination is taken into account, efficien

Francisco C. Caramello

We introduce orbifolds from the classical point of view, using charts, and present orbifold versions of elementary objects from Algebraic Topology, such as the fundamental group, coverings and Euler characteristic; Differential Topology/Geometry, including orbibundles, differential forms, integration and (equivariant) De Rham cohomology; and Riemannian Geome

Nathaniel S Wilson, Stephan Kraemer, Daniel J. Pennachio, Patrick Callahan

We report a novel growth mechanism that produces in-plane [1-10] oriented ErSb nanowires formed during codeposition of Er0.3Ga0.7Sb via molecular beam epitaxy (MBE). Nanowires are characterized by in-situ scanning tunneling microscopy (STM), as well as ex-situ transmission electron microscopy (TEM) and electron channeling contrast imaging (ECCI). We show tha

Elliot Creager, David Madras, Toniann Pitassi, Richard Zemel

In many application areas---lending, education, and online recommenders, for example---fairness and equity concerns emerge when a machine learning system interacts with a dynamically changing environment to produce both immediate and long-term effects for individuals and demographic groups. We discuss causal directed acyclic graphs (DAGs) as a unifying frame

Tomáš Nagy

We prove that a non-affine latin quandle (also known as left distributive quasigroup) of order $2^k$ exists if and only if $k = 6$ or $k \geq 8$. The construction is expressed in terms of central extensions of affine quandles.

S. Arthamonov, N. Reshetikhin

The main result of this paper is the construction of a family of superintegrable Hamiltonian systems on moduli spaces of flat connections on a principle $G$-bundle on a surface. The moduli space is a Poisson variety with Atiyah-Bott Poisson structure. Among particular cases of such systems are spin generalizations of Ruijsenaars-Schneider models.

Daniel Faraco, Sauli Lindberg, László Székelyhidi

We show that in 3-dimensional ideal magnetohydrodynamics there exist infinitely many bounded solutions that are compactly supported in space-time and have non-trivial velocity and magnetic fields. The solutions violate conservation of total energy and cross helicity, but preserve magnetic helicity. For the 2-dimensional case we show that, in contrast, no non

Diganta Das

Inspired by the recent hints of lepton flavor universality violation in $b\to s\ell\ell$ and $b\to c\ellν$ transitions, we study lepton flavor violating exclusive $Λ_b\toΛ\ell_1^+\ell_2^-$ ($\ell_1\neq \ell_2$) decay, which is forbidden in the Standard Model. Starting from a general effective Hamiltonian for a $b\to s\ell_1^+\ell_2^-$ transition that include

L. Mancini, P. Sarkis, Th. Henning, G. A. Bakos

The transiting exoplanetary system WASP-174 was reported to be composed by a main-sequence F star (V=11.8 mag) and a giant planet, WASP-174b (orbital period 4.23 days). However only an upper limit was placed on the planet mass (<1.3 Mj), and a highly uncertain planetary radius (0.7-1.7 Rj) was determined. We aim to better characterise both the star and the p

A. A. Aligia, D. Pérez Daroca, L. Arrachea, P. Roura Bas

We study the heat current through two capacitively coupled quantum dots coupled in series with two conducting leads at different temperatures $T_L$ and $T_R$ in the spinless case (valid for a high applied magnetic field). Our results are also valid for the heat current through a single quantum dot with strongly ferromagnetic leads pointing in opposite direct

Siyuan Shan, Yang Li, Junier Oliva

Making an adaptive prediction based on one's input is an important ability for general artificial intelligence. In this work, we step forward in this direction and propose a semi-parametric method, Meta-Neighborhoods, where predictions are made adaptively to the neighborhood of the input. We show that Meta-Neighborhoods is a generalization of $k$-nearest-nei

Theodore A. Marschall, Daniel Van Hoesen, S. Teitel

We use numerical simulations to study the flow of a bidisperse mixture of athermal, frictionless, soft-core two dimensional spherocylinders driven by a uniform steady-state simple shear applied at a fixed volume and a fixed finite strain rate $\dot\gamma$. Energy dissipation is via a viscous drag with respect to a uniformly sheared host fluid, giving a simpl

Maxim Derevyagin, Gerald V. Dunne, Gamal Mograby, Alexander Teplyaev

In the quest for designing novel protocols for quantum information and quantum computation, an important goal is to achieve perfect quantum state transfer for systems beyond the well-known one dimensional cases, such as 1d spin chains. We use methods from fractal analysis and probability to find a new class of quantum spin chains on fractal-like graphs (know

Y. Chen, K. Ji, Z. Y. Xie, J. F. Yu

With an auxiliary weak external magnetic field, we reexamine the fundamental thermodynamic function, Gibbs free energy F(T, h), to study the phase transitions in the classical spin lattice models. A cross derivative, i.e. the second-order partial derivative of F(T, h) with respect to both temperature and field, is calculated to precisely locate the critical

Colin Guillarmou, Gerhard Knieper, Thibault Lefeuvre

We refine the recent local rigidity result for the marked length spectrum obtained by the first and third author in \cite{Guillarmou-Lefeuvre-18} and give an alternative proof using the geodesic stretch between two Anosov flows and some uniform estimate on the variance appearing in the central limit theorem for Anosov geodesic flows. In turn, we also introdu

Oliver Rhodes, Luca Peres, Andrew G. D. Rowley, Andrew Gait

Real-time simulation of a large-scale biologically representative spiking neural network is presented, through the use of a heterogeneous parallelisation scheme and SpiNNaker neuromorphic hardware. A published cortical microcircuit model is used as a benchmark test case, representing approx. 1 square mm of early sensory cortex, containing 77k neurons and 0.3

Eyyüb Sari, Mouloud Belbahri, Vahid Partovi Nia

Binary Neural Networks (BNNs) are difficult to train, and suffer from drop of accuracy. It appears in practice that BNNs fail to train in the absence of Batch Normalization (BatchNorm) layer. We find the main role of BatchNorm is to avoid exploding gradients in the case of BNNs. This finding suggests that the common initialization methods developed for full-

Wang Jing, M. A. Kelly, David Reitter

Native speakers can judge whether a sentence is an acceptable instance of their language. Acceptability provides a means of evaluating whether computational language models are processing language in a human-like manner. We test the ability of computational language models, simple language features, and word embeddings to predict native English speakers judg

Dangxing Chen

The leverage effect refers to the generally negative correlation between the return of an asset and the changes in its volatility. There is broad agreement in the literature that the effect should be present for theoretical reasons, and it has been consistently found in empirical work. However, a few papers have pointed out a puzzle: the return distributions

Moritz Hoferer, Silvia Bonfanti, Alessandro Taloni, Caterina A. M. La Porta

Lipid rafts are heterogeneous dynamic lipid domains of the cell membranes that are involved in several biological processes, like protein and lipids specific transport and signaling. Our understanding of lipid raft formation is still limited, due to the transient and elusive nature of these domains {\it in vivo}, in contrast to the stable phase-separated dom

Martin Bauer, Philipp Harms, Peter W. Michor

We prove that the geodesic equations of all Sobolev metrics of fractional order one and higher on spaces of diffeomorphisms and, more generally, immersions are locally well posed. This result builds on the recently established real analytic dependence of fractional Laplacians on the underlying Riemannian metric. It extends several previous results and applie

Rafael Guerço, Katia Cunha, Verne V. Smith, Christian R. Hayes

The chemical evolution of fluorine is investigated in a sample of Milky Way red giantstars that span a significant range in metallicity from [Fe/H] $\sim$ -1.3 to 0.0 dex. Fluorine abundances are derived from vibration-rotation lines of HF in high-resolution infraredspectra near $λ$ 2.335 $μ$m. The red giants are members of the thin and thick disk / halo,wit

Bjorn K. Berntson, Ian Marquette, Willard Miller

We revise a method by Kalnins, Kress and Miller (2010) for constructing a canonical form for symmetry operators of arbitrary order for the Schr\"odinger eigenvalue equation $H\Psi \equiv (\Delta_2 +V)\Psi=E\Psi$ on any 2D Riemannian manifold, real or complex, that admits a separation of variables in some orthogonal coordinate system. Most of this paper is de

Yoon-Seok Choun

In 1985, G\"ursey showed that the spectrum of the semi-relativistic Hamiltonian for the bag model, introduced by Lichtenberg et al. for mesons, follows the Regge trajectory if the current quark mass is negligible. The model leads to the biconfluent Heun equation, which is a second-order linear ordinary differential equation (ODE) with a regular singularity a

Lei You, Di Yuan

In this technical note, we present a new theoretical result for resource optimization with non-orthogonal multiple access (NOMA). For multi-cell scenarios, a so-called load-coupling model has been proposed to characterize the presence of mutual interference for NOMA, and resource optimization relies on the use of fixed-point iterations [1], [2] across cells.

Pierre Flurin, Steve Zelditch

Associated to the Bergman kernels of a polarized toric Kaehler manifold $(M, \omega, L, h)$ are sequences of measures $\{\mu_k^z\}_{k=1}^{\infty}$ parametrized by the points $z \in M$. We determine the asymptotics of the entropies $H(\mu_k^z)$ of these measures. The sequence $\mu_k^z$ in some ways resembles a sequence of convolution powers; we determine prec

S. Wang, J. Y. Che, C. Chen, G. G. Xin

We study the ionization dynamics of oriented HeH$^+$ in strong linearly-polarized laser fields by numerically solving the time-dependent Schr\"{o}dinger equation. The calculated photoelectron momentum distributions for parallel orientation show a striking asymmetric structure. With a developed model pertinent to polar molecules, we trace the electron motion

Tianci Zhou, Shenglong Xu, Xiao Chen, Andrew Guo

We argue that chaotic power-law interacting systems have emergent limits on information propagation, analogous to relativistic light cones, which depend on the spatial dimension $d$ and the exponent $\alpha$ governing the decay of interactions. Using the dephasing nature of quantum chaos, we map the problem to a stochastic model with a known phase diagram. A

J. S. Hazboun, J. Simon, S. R. Taylor, M. T. Lam

An ensemble of inspiraling supermassive black hole binaries should produce a stochastic background of very low frequency gravitational waves. This stochastic background is predicted to be a power law, with a spectral index of -2/3, and it should be detectable by a network of precisely timed millisecond pulsars, widely distributed on the sky. This paper repor

Noé Cuneo

Motivated by various applications and examples, the standard notion of potential for dynamical systems has been generalized to almost additive and asymptotically additive potential sequences, and the corresponding thermodynamic formalism, dimension theory and large deviations theory have been extensively studied in the recent years. In this paper, we show th

Domenico Orlando, Susanne Reffert, Francesco Sannino

We investigate four-dimensional near-conformal dynamics by means of the large-charge limit. We first introduce and justify the formalism in which near-conformal invariance is insured by adding a dilaton and then determine the large-charge spectrum of the theory. The dilaton can also be viewed as the radial mode of the EFT. We calculate the two-point function

Agustin Di Paolo, Panagiotis Kl. Barkoutsos, Ivano Tavernelli, Alexandre Blais

We propose the simulation of quantum-optical systems in the ultrastrong-coupling regime using a variational quantum algorithm. More precisely, we introduce a short-depth variational form to prepare the groundstate of the multimode Dicke model on a quantum processor and present proof-of-principle results obtained via cloud access to an IBM device. We moreover

J. H-H. Chan, M. Millon, V. Bonvin, F. Courbin

With the advent of high-cadence and multi-band photometric monitoring facilities, continuum reverberation mapping is becoming of increasing importance to measure the physical size of quasar accretion disks. The method is based on the measurement of the time it takes for a signal to propagate from the center to the outer parts of the central engine, assuming

Xue-Yang Song, Yin-Chen He, Ashvin Vishwanath, Chong Wang

We develop a nonperturbative approach to the bulk polarization of crystalline electric insulators in $d\geq1$ dimensions. Formally, we define polarization via the response to background fluxes of both charge and lattice translation symmetries. In this approach, the bulk polarization is related to properties of magnetic monopoles under translation symmetries.

Yang Peng

Floquet higher-order topological insulators and superconductors (HOTI/SCs) with an order-two space-time symmetry or antisymmetry are classified. This is achieved by considering unitary loops, whose nontrivial topology leads to the anomalous Floquet topological phases, subject to a space-time symmetry/antisymmetry. By mapping these unitary loops to static Ham

Oliver Hart, Yuan Wan, Claudio Castelnovo

The appearance of quasiparticle excitations with fractional statistics is a remarkable defining trait of topologically ordered systems. In this work, we investigate the experimentally relevant finite temperature regime in which one species of quasiparticle acts as a stochastic background for another, more energetically costly, species that hops coherently ac

Kyrylo Bondarenko, Alexey Boyarsky, Torsten Bringmann, Marco Hufnagel

Traditional direct searches for dark matter, looking for nuclear recoils in deep underground detectors, are challenged by an almost complete loss of sensitivity for light dark matter particles. Consequently, there is a significant effort in the community to devise new methods and experiments to overcome these difficulties, constantly pushing the limits of th

Matteo Lucca, Laura Sagunski

Although the main features of the evolution of binary neutron star systems are now well established, many details are still subject to debate, especially regarding the post-merger phase. In particular, the lifetime of the hyper-massive neutron stars formed after the merger is very hard to predict. In this work, we provide a simple analytic relation for the l

Pramod Shukla

In the context of realizing de-Sitter vacua and the slow-roll inflation, several no-go conditions have been found in the framework of type IIA (generalized) flux compactifications. In this article, using our recently proposed $T$-dual dictionary in arXiv:1909.07391, we translate various such type IIA no-go conditions which subsequently leads to some interest

Niccolò Cribiori, Renata Kallosh, Christoph Roupec, Timm Wrase

A simple, KKLT-like construction of de Sitter vacua in type IIA string theory is presented in an STU model with guidance from string theory U-duality and with an uplifting anti-D6-brane. In four dimensions the model is reduced to $\mathcal{N}=1$ supergravity with three chiral multiplets, namely $S$, $T$ and $U$, as well as one nilpotent multiplet representin

Suvodip Mukherjee, Guilhem Lavaux, François R. Bouchet, Jens Jasche

Gravitational wave (GW) sources are an excellent probe of the luminosity distance and offer a novel measure of the Hubble constant, $H_0$. This estimation of $H_0$ from standard sirens requires an accurate estimation of the cosmological redshift of the host galaxy of the GW source, after correcting for its peculiar velocity. Absence of an accurate peculiar v

Arthur Hebecker, Torben Skrzypek, Manuel Wittner

We attempt a systematic analysis of string-theoretic quintessence models as an alternative to metastable de Sitter vacua. It appears that, within the boundaries of what is known, large-volume type-IIB flux compactifications are preferred. Here the quintessence scalar is the ratio of certain 4-cycle volumes. It has already been noticed that the volume modulus

IceCube Collaboration, M. G. Aartsen, M. Ackermann, J. Adams

The presence of a population of point sources in a dataset modifies the underlying neutrino-count statistics from the Poisson distribution. This deviation can be exactly quantified using the non-Poissonian template fitting technique, and in this work we present the first application this approach to the IceCube high-energy neutrino dataset. Using this method

Patrick E. Nelson, Zachariah B. Etienne, Sean T. McWilliams, Viviana Nguyen

When two relativistically boosted, nonspinning black holes pass by one another on a scattering trajectory, we might expect the tidal interaction to spin up each black hole. We present the first exploration of this effect, appearing at fourth post-Newtonian order, with full numerical relativity calculations. The basic setup for the calculations involves two f

Thomas Connor, Eduardo Bañados, Daniel Stern, Roberto Decarli

Quasars at early redshifts ($z > 6$) with companion galaxies offer unique insights into the growth and evolution of the first supermassive black holes. Here, we report on a 150 ks Chandra observation of PSO J308.0416$-$21.2339, a $z=6.23$ quasar with a merging companion galaxy identified in [C II] and rest-frame UV emission. With $72.3^{+9.6}_{-8.6}$ net cou

Bastien Lapierre, Kenny Choo, Clément Tauber, Apoorv Tiwari

While driven interacting quantum matter is generically subject to heating and scrambling, certain classes of systems evade this paradigm. We study such an exceptional class in periodically driven critical (1 + 1)-dimensional systems with a spatially modulated, but disorder-free time evolution operator. Instead of complete scrambling, the excitations of the s

Pan Xu, Felicia Gao, Quanquan Gu

Improving the sample efficiency in reinforcement learning has been a long-standing research problem. In this work, we aim to reduce the sample complexity of existing policy gradient methods. We propose a novel policy gradient algorithm called SRVR-PG, which only requires $O(1/\epsilon^{3/2})$ episodes to find an $\epsilon$-approximate stationary point of the

HAWC Collaboration, A. U. Abeysekara, A. Albert, R. Alfaro

We present the first catalog of gamma-ray sources emitting above 56 and 100 TeV with data from the High Altitude Water Cherenkov (HAWC) Observatory, a wide field-of-view observatory capable of detecting gamma rays up to a few hundred TeV. Nine sources are observed above 56 TeV, all of which are likely Galactic in origin. Three sources continue emitting past

Renos Karamanis, Eleftherios Anastasiadis, Panagiotis Angeloudis, Marc Stettler

Transportation Network Companies employ dynamic pricing methods at periods of peak travel to incentivise driver participation and balance supply and demand for rides. Surge pricing multipliers are commonly used and are applied following demand and estimates of customer and driver trip valuations. Combinatorial double auctions have been identified as a suitab

Heng Yang, Pasquale Antonante, Vasileios Tzoumas, Luca Carlone

Semidefinite Programming (SDP) and Sums-of-Squares (SOS) relaxations have led to certifiably optimal non-minimal solvers for several robotics and computer vision problems. However, most non-minimal solvers rely on least-squares formulations, and, as a result, are brittle against outliers. While a standard approach to regain robustness against outliers is to

M. Gadella, J. M. Mateos Guilarte, J. M. Muñoz-Castañeda, L. M. Nieto

We present a detailed study of a generalised one-dimensional Kronig-Penney model using $\delta\text{-}\delta'$ potentials. We analyse the band structure and the density of states in two situations. In the first case we consider an infinite array formed by identical $\delta\text{-}\delta'$ potentials standing at the linear lattice nodes. This case will be kno

Yorie Nakahira, Quanying Liu, Terrence J. Sejnowski, John C. Doyle

Nervous systems sense, communicate, compute and actuate movement using distributed components with severe trade-offs in speed, accuracy, sparsity, noise and saturation. Nevertheless, brains achieve remarkably fast, accurate, and robust control performance due to a highly effective layered control architecture. Here we introduce a driving task to study how a

A. Fannjiang, Z. Zhang

Douglas-Rachford Splitting (DRS) methods based on the proximal point algorithms for the Poisson and Gaussian log-likelihood functions are proposed for ptychography and phase retrieval. Fixed point analysis shows that the DRS iterated sequences are always bounded explicitly in terms of the step size and that the fixed points are attracting if and only if the

Kyriakos Destounis

The theory of General Relativity predicts that black holes are a natural constituent of our Universe. Before a black hole binary relaxes to a final state, it undergoes damped oscillations which completely characterize the final object. These oscillations are described by quasinormal modes which are present in many dissipative systems. Quasinormal modes are l

Zhi-Hao Cui, Tianyu Zhu, Garnet Kin-Lic Chan

We describe an efficient quantum embedding framework for realistic ab initio density matrix embedding (DMET) calculations in solids. We discuss in detail the choice of orbitals and mapping to a lattice, treatment of the virtual space and bath truncation, and the lattice-to embedded integral transformation. We apply DMET in this ab initio framework to a hexag

Daniel M. Ziegler, Nisan Stiennon, Jeffrey Wu, Tom B. Brown

Reward learning enables the application of reinforcement learning (RL) to tasks where reward is defined by human judgment, building a model of reward by asking humans questions. Most work on reward learning has used simulated environments, but complex information about values is often expressed in natural language, and we believe reward learning for language

Tianyu Zhu, Zhi-Hao Cui, Garnet Kin-Lic Chan

We present an efficient ab initio dynamical mean-field theory (DMFT) implementation for quantitative simulations in solids. Our DMFT scheme employs ab initio Hamiltonians defined for impurities comprising the full unit cell or a supercell of atoms and for realistic quantum chemical basis sets. We avoid double counting errors by using Hartree-Fock as the low-

Ewain Gwynne

Let $\gamma \in (0,2)$, let $h$ be the planar Gaussian free field, and consider the $\gamma$-Liouville quantum gravity (LQG) metric associated with $h$. We show that the essential supremum of the Hausdorff dimension of the boundary of a $\gamma$-LQG metric ball with respect to the Euclidean (resp. $\gamma$-LQG) metric is $2 - \frac{\gamma}{d_\gamma}\left(\fr

Myoung-Woo Yoo, Damien Rontani, Jérémy Létang, Sébastien Petit-Watelot

Harnessing chaos or intrinsic nonlinear behaviours from dynamical systems is a promising avenue for the development of unconventional information processing technologies. However, the exploitation of such features in spintronic devices has not been attempted despite the many theoretical and experimental evidence of nonlinear behaviour of the magnetization dy

Hariharan Narayanan

We show that a random concave function having a periodic hessian on an equilateral lattice has a quadratic scaling limit, if the average hessian of the function satisfies certain conditions. We consider the set of all concave functions $g$ on an equilateral lattice $\mathbb L$ that when shifted by an element of $n \mathbb L$, incur addition by a linear funct

Stephan Hellmich, Stefano Mottola, Gerhard Hahn, Ekkehard Kührt

Aims. We investigate the influence of the Yarkovsky force on the long-term orbital evolution of Jupiter Trojan asteroids. Methods. Clones of the observed population with different sizes and different thermal properties were numerically integrated for 1 Gyr with and without the Yarkovsky effect. The escape rate of these objects from the Trojan region as well

Sander Greenland, Zad Rafi, Robert Matthews, Megan Higgs

All scientific interpretations of statistical outputs depend on background (auxiliary) assumptions that are rarely delineated or explicitly interrogated. These include not only the usual modeling assumptions, but also deeper assumptions about the data-generating mechanism that are implicit in conventional statistical interpretations yet are unrealistic in mo

Benjamin Jaye, Xavier Tolsa, Michele Villa

In this paper we provide a proof of the Carleson $\varepsilon^2$-conjecture. This result yields a characterization (up to exceptional sets of zero length) of the tangent points of a Jordan curve in terms of the finiteness of the associated Carleson $\varepsilon^2$-square function.

Zad Rafi, Sander Greenland

Researchers often misinterpret and misrepresent statistical outputs. This abuse has led to a large literature on modification or replacement of testing thresholds and $P$-values with confidence intervals, Bayes factors, and other devices. Because the core problems appear cognitive rather than statistical, we review simple aids to statistical interpretations.

Stefan Wolff, Fearghal O'Donncha, Bei Chen

In situ and remotely sensed observations have potential to facilitate data-driven predictive models for oceanography. A suite of machine learning models, including regression, decision tree and deep learning approaches were developed to estimate sea surface temperatures (SST). Training data consisted of satellite-derived SST and atmospheric data from The Wea

Cyrille Marquet, Shu-Yi Wei, Bo-Wen Xiao

We calculate and compare the differential cross sections for forward $Z^0$-boson production at small transverse momentum, in proton-proton and proton-nucleus collisions, using both the collinear and dilute-dense factorization frameworks. In both cases, we implement a Sudakov resummation of the large logarithms generated by soft-gluon emissions, which is esse

A. Ioannisian

We study the dependence of neutral current (NC) neutrino-induced $π^0$/photon production ($ν_μ+ A \to ν_μ+1π^0 / γ+ X$) on the atomic number of the target nucleus, A, at 4-momentum transfers relevant to the MiniBooNE experiment: $Δ$ resonance mass region. Our conclusion is based on experimental data for photon-nucleus interactions from the A2 collaboration a

Samyobrata Mukherjee, Jordi Gomis-Bresco, Pilar Pujol-Closa, David Artigas

Waveguiding structures made of anisotropic media support bound states in the continuum (BICs) that arise when the radiation channel of otherwise semi-leaky modes is suppressed. Hitherto, only structures with optical axes aligned in symmetric orientations inside the waveguide plane, where BICs appear as lines in the momentum-frequency dispersion diagram, have

Samuel T. Mister, Benjamin J. Arayathel, Anthony J. Short

We show that probability is locally conserved in discrete time quantum walks, corresponding to a particle evolving in discrete space and time. In particular, for a spatial structure represented by an arbitrary directed graph, and any unitary evolution of a particle which respects that locality structure, we can define probability currents which also respect

Rupert Coy, Michele Frigerio, Federico Mescia, Olcyr Sumensari

We investigate new-physics contributions to $b\to s \ell\ell$ transitions in the context of an effective field theory extension of the Standard Model, including operator mixing at one loop. We identify the few scenarios where a single Wilson coefficient, $C/\Lambda^2 \sim 1/{\rm TeV}^2$, induces a substantial shift in the lepton flavour universality ratios $

Huziel E. Sauceda, Stefan Chmiela, Igor Poltavsky, Klaus-Robert Müller

Highly accurate force fields are a mandatory requirement to generate predictive simulations. Here we present the path for the construction of machine learned molecular force fields by discussing the hierarchical pathway from generating the dataset of reference calculations to the construction of the machine learning model, and the validation of the physics g

Olimjon Eshkobilov, Emilio Musso, Lorenzo Nicolodi

Explicit models for the restricted conformal group of the Einstein static universe of dimension greater than two and for its universal covering group are constructed. Based on these models, as an application we determine all oriented and time-oriented conformal Lorentz manifolds whose restricted conformal group has maximal dimension. They amount to the Einst

Ming Zhang, Jie Jiang, Zhen Zhong

In the eikonal regime, we analytically calculate quasinormal resonance frequencies for massless scalar perturbations of the higher-dimensional Reissner--Nordström (RN) black holes. Remarkably, we find that the higher-dimensional RN black holes coupled with the massless scalar fields have the fastest relaxation rates in the Schwarzschild limit, this is qualit

Wen-Loong Ma, Aaron D Ames

This paper systematically decomposes a quadrupedal robot into bipeds to rapidly generate walking gaits and then recomposes these gaits to obtain quadrupedal locomotion. We begin by decomposing the full-order, nonlinear and hybrid dynamics of a three-dimensional quadrupedal robot, including its continuous and discrete dynamics, into two bipedal systems that a

Lukas Diekmann, Laurence Tratt

Since composed grammars are often ambiguous, grammar composition requires a mechanism for dealing with ambiguity: either ruling it out by using delimiters (which are awkward to work with), or by using disambiguation operators to filter a parse forest down to a single parse tree (where, in general, we cannot be sure that we have covered all possible parse for