cssi/SciSciGPT-SciSciNet huggingface dataset:
JOINT MODELING OF MULTIPLE TIME SERIES VIA THE BETA PROCESS WITH APPLICATION TO MOTION CAPTURE SEGMENTATION

We propose a Bayesian nonparametric approach to the problem of jointly modeling multiple related time series. Our model discovers a latent set of dynamical behaviors shared among the sequences, and segments each time series into regions defined by a subset of these behaviors. Using a beta process prior, the size of the behavior set and the sharing pattern are both inferred from data. We develop Markov chain Monte Carlo (MCMC) methods based on the Indian buffet process representation of the predictive distribution of the beta process. Our MCMC inference algorithm efficiently adds and removes behaviors via novel split-merge moves as well as data-driven birth and death proposals, avoiding the need to consider a truncated model. We demonstrate promising results on unsupervised segmentation of human motion capture data. 1. Introduction. Classical time series analysis has generally focused on the study of a single (potentially multivariate) time series. Instead, we consider analyzing collections of related time series, motivated by the increasing abundance of such data in many domains. In this work we explore this problem by considering time series produced by motion capture sensors on the joints of people performing exercise routines. An individual recording provides a multivariate time series that can be segmented into types of exercises (e.g., jumping jacks, arm-circles, and twists). Each exercise type describes locally coherent and simple dynamics that persist over a segment of time. We have such motion capture recordings from multiple individuals, each of whom performs some subset of a global set of exercises, as shown in Figure1. Our goal is to discover the set of global exercise types (“behaviors”) and their occurrences in each individual’s data stream. We would like to take advantage of the overlap between individuals: if a jumping-jack behavior is discovered in one sequence, then it can be used to model data for other individuals.
Toward a stability theory of tame abstract elementary classes

We initiate a systematic investigation of the abstract elementary classes that have amalgamation, satisfy tameness (a locality property for orbital types), and are stable (in terms of the number of...
Creation of a low-entropy quantum gas of polar molecules in an optical lattice

Ultracold polar molecules, with their long-range electric dipolar interactions, offer a unique platform for studying correlated quantum many-body phenomena. However, realizing a highly degenerate quantum gas of molecules with a low entropy per particle is challenging. We report the synthesis of a low-entropy quantum gas of potassium-rubidium molecules (KRb) in a three-dimensional optical lattice. We simultaneously load into the optical lattice a Mott insulator of bosonic Rb atoms and a single-band insulator of fermionic K atoms. Then, using magnetoassociation and optical state transfer, we efficiently produce ground-state molecules in the lattice at those sites that contain one Rb and one K atom. The achieved filling fraction of 25% should enable future studies of transport and entanglement propagation in a many-body system with long-range dipolar interactions.
Matrix operators for complex interferometer analysis

A modeling methodology and matrix formalism is presented that permits analysis of arbitrarily complex interferometric waveguide systems, including polarization and backreflection effects. Considerable improvement results from separation of the dependencies on connection topology from the dependencies on the devices and their specifications. A non-commutative operator and embedding matrices are introduced allowing a compact depiction of the salient optical equations, and straightforward calculation of the amplitude and intensity transfer functions.
Magnetic Faraday rotation in lossy photonic structures

Magnetic Faraday rotation is widely used in optics and microwaves (MW). In uniform magneto-optical materials, this effect is very weak. One way to enhance it is to incorporate the magnetic material into a high-Q optical resonator. One problem with magneto-optical resonators is that along with Faraday rotation, the absorption and linear birefringence can also increase dramatically, compromising the device performance. We discuss how this problem can be addressed in the cases of optical microcavities and slow wave resonators. We show that a slow wave resonator has a fundamental advantage when it comes to Faraday rotation enhancement in lossy magnetic materials.
Three Dimensional Blind Image Deconvolution for Fluorescence Microscopy using Generative Adversarial Networks

Due to image blurring image deconvolution is often used for studying biological structures in fluorescence microscopy. Fluorescence microscopy image volumes inherently suffer from intensity inhomogeneity, blur, and are corrupted by various types of noise which exacerbate image quality at deeper tissue depth. Therefore, quantitative analysis of fluorescence microscopy in deeper tissue still remains a challenge. This paper presents a three dimensional blind image deconvolution method for fluorescence microscopy using 3way spatially constrained cycle-consistent adversarial networks. The restored volumes of the proposed deconvolution method and other well-known deconvolution methods, denoising methods, and an inhomogeneity correction method are visually and numerically evaluated. Experimental results indicate that the proposed method can restore and improve the quality of blurred and noisy deep depth microscopy image visually and quantitatively.
Developing and Improving Risk Models using Machine-learning Based Algorithms

The objective of this study is to develop a good risk model for classifying business delinquency by simultaneously exploring several machine learning based methods including regularization, hyper-parameter optimization, and model ensembling algorithms. The rationale under the analyses is firstly to obtain good base binary classifiers (include Logistic Regression (LR), K-Nearest Neighbors (KNN), Decision Tree (DT), and Artificial Neural Networks (ANN)) via regularization and appropriate settings of hyper-parameters. Then two model ensembling algorithms including bagging and boosting are performed on the good base classifiers for further model improvement. The models are evaluated using accuracy, Area Under the Receiver Operating Characteristic Curve (AUC of ROC), recall, and F1 score via repeating 10-fold cross-validation 10 times. The results show the optimal base classifiers along with the hyper-parameter settings are LR without regularization, KNN by using 9 nearest neighbors, DT by setting the maximum level of the tree to be 7, and ANN with three hidden layers. Bagging on KNN with K valued 9 is the optimal model we can get for risk classification as it reaches the average accuracy, AUC, recall, and F1 score valued 0.90, 0.93, 0.82, and 0.89, respectively.
On the Decay of Correlations in the Random Field Ising Model

In a celebrated 1990 paper, Aizenman and Wehr proved that the two-dimensional random field Ising model has a unique infinite volume Gibbs state at any temperature. The proof is ergodic-theoretic in nature and does not provide any quantitative information. This article proves the first quantitative version of the Aizenman–Wehr theorem. The proof introduces a new method for proving decay of correlations that may be interesting in its own right. A fairly detailed sketch of the main ideas behind the proof is also included.
Virtualized Logical Qubits: A 2.5D Architecture for Error-Corrected Quantum Computing

Current, near-term quantum devices have shown great progress in the last several years culminating recently with a demonstration of quantum supremacy. In the medium-term, however, quantum machines will need to transition to greater reliability through error correction, likely through promising techniques like surface codes which are well suited for near-term devices with limited qubit connectivity. We discover quantum memory, particularly resonant cavities with transmon qubits arranged in a 2.5D architecture, can efficiently implement surface codes with substantial hardware savings and performance/fidelity gains. Specifically, we virtualize logical qubits by storing them in layers of qubit memories connected to each transmon.Surprisingly, distributing each logical qubit across many memories has a minimal impact on fault tolerance and results in substantially more efficient operations. Our design permits fast transversal application of CNOT operations between logical qubits sharing the same physical address (same set of cavities) which are 6x faster than standard lattice surgery CNOTs. We develop a novel embedding which saves approximately 10x in transmons with another 2x savings from an additional optimization for compactness.Although qubit virtualization pays a 10x penalty in serialization, advantages in the transversal CNOT and in area efficiency result in fault-tolerance and performance comparable to conventional 2D transmon-only architectures. Our simulations show our system can achieve fault tolerance comparable to conventional two-dimensional grids while saving substantial hardware. Furthermore, our architecture can produce magic states at 1.22x the baseline rate given a fixed number of transmon qubits. This is a critical benchmark for future fault-tolerant quantum computers as magic states are essential and machines will spend the majority of their resources continuously producing them. This architecture substantially reduces the hardware requirements for fault-tolerant quantum computing and puts within reach a proof-of-concept experimental demonstration of around 10 logical qubits, requiring only 11 transmons and 9 attached cavities in total.
Periodic flats and group actions on locally symmetric spaces

The goal of this paper is to give some new results of the flavor that ‘the locally symmetric metric on a locally symmetric manifold is the most symmetric metric on that manifold’. Earlier work, reviewed below, establishes such results for compact manifolds. Our goal here is to dispense with compactness, resulting in new obstacles and phenomena. Let .M;g/ be a complete Riemannian manifold homeomorphic to a finite volume, nonpositively curved locally symmetric space with no local torus factors. In this paper we prove that the metric g has no homotopically trivial isometries. More precisely, the isometry group Isom.M;g/ acts on free homotopy classes of loops and this gives an action homomorphism
THE COSMOLOGICAL SPACETIME

We present here the transformations required to recast the Robertson–Walker metric and Friedmann–Robertson–Walker equations in terms of observer-dependent coordinates for several commonly assumed cosmologies. The overriding motivation is the derivation of explicit expressions for the radius Rh of our cosmic horizon in terms of measurable quantities for each of the cases we consider. We show that the cosmological time dt diverges for any finite interval ds associated with a process at R → Rh, which therefore represents a physical limit to our observations. This is a key component required for a complete interpretation of the data, particularly as they pertain to the nature of dark energy. With these results, we affirm the conclusion drawn in our earlier work that the identification of dark energy as a cosmological constant does not appear to be consistent with the data.
Covert communications on Poisson packet channels

Consider a channel where authorized transmitter Jack sends packets to authorized receiver Steve according to a Poisson process with rate λ packets per second for a time period T. Suppose that covert transmitter Alice wishes to communicate information to covert receiver Bob on the same channel without being detected by a watchful adversary Willie. We consider two scenarios. In the first scenario, we assume that warden Willie cannot look at packet contents but rather can only observe packet timings, and Alice must send information by inserting her own packets into the channel. We show that the number of packets that Alice can covertly transmit to Bob is on the order of the square root of the number of packets that Jack transmits to Steve; conversely, if Alice transmits more than that, she will be detected by Willie with high probability. In the second scenario, we assume that Willie can look at packet contents but that Alice can communicate across an M/M/1 queue to Bob by altering the timings of the packets going from Jack to Steve. First, Alice builds a codebook, with each codeword consisting of a sequence of packet timings to be employed for conveying the information associated with that codeword. However, to successfully employ this codebook, Alice must always have a packet to send at the appropriate time. Hence, leveraging our result from the first scenario, we propose a construction where Alice covertly slows down the packet stream so as to buffer packets to use during a succeeding codeword transmission phase. Using this approach, Alice can covertly and reliably transmit O(λT) covert bits to Bob in time period T over an M/M/1 queue with service rate μ > e · λ.
On the accuracy of retinal protonated Schiff base models

We investigate the molecular geometries of the ground state and the minimal energy conical intersections between the ground and first excited states of the models for the retinal protonated Schiff ...
Chemical migration and dipole formation at van der Waals interfaces between magnetic transition metal chalcogenides and topological insulators

Interfaces between topological insulators (TIs) and magnetic materials, including 2D van der Waals magnets, are currently generating enormous interest, due to phenomena such as the quantum anomalous Hall effect. Many of the magnets employed contain reactive and diffusive elements such as Mn, however, raising serious materials challenges. This work explores the interface between Bi${}_{2}$Se${}_{3}$ and Mn and MnSe, revealing chemical and electronic changes at the interface depending on how Mn is deposited. Mn deposited without excess selenium shows Se out-diffusion from Bi${}_{2}$Se${}_{3}$ to the Mn. Supplying excess Se alongside Mn prevents this Se out-diffusion, but the interface becomes affected by a negative surface dipole. This dipole forms due to preferential creation of $\ensuremath{\alpha}$-MnSe(111) over the 1T-MnSe${}_{2}$ phase. This study shows that chemical diffusion and dipole formation are important for Mn-Bi${}_{2}$Se${}_{3}$ and MnSe${}_{2\ensuremath{-}x}$-Bi${}_{2}$Se${}_{3}$ interfaces and must generally be considered at TI/Mn chalcogenide interfaces.
Synchronous correlation matrices and Connes’ embedding conjecture

In the work of Paulsen et al. [J. Funct. Anal. (in press); preprint arXiv:1407.6918], the concept of synchronous quantum correlation matrices was introduced and these were shown to correspond to traces on certain C*-algebras. In particular, synchronous correlation matrices arose in their study of various versions of quantum chromatic numbers of graphs and other quantum versions of graph theoretic parameters. In this paper, we develop these ideas further, focusing on the relations between synchronous correlation matrices and microstates. We prove that Connes’ embedding conjecture is equivalent to the equality of two families of synchronous quantum correlation matrices. We prove that if Connes’ embedding conjecture has a positive answer, then the tracial rank and projective rank are equal for every graph. We then apply these results to more general non-local games.
Galaxies Probing Galaxies at High Resolution: Co-Rotating Gas Associated with a Milky Way Analog at z=0.4

Author(s): Diamond-Stanic, Aleksandar M; Coil, Alison L; Moustakas, John; Tremonti, Christy A; Sell, Paul H; Mendez, Alexander J; Hickox, Ryan C; Rudnick, Greg H
Sound waves move matter

This paper agrees with a recent claim that sound waves carry gravitational mass. The author starts from Newton's second law applied at second order in the amplitude of the small sound oscillations to obtain this result. In a plane wave packet moving to the right, the atoms vibrate and end up displaced a small amount to the left.
Localization, Dirac fermions and Onsager universality

Disordered systems exhibiting exponential localization are mapped to anisotropic spin chains with localization length being related to the anisotropy of the spin model. This relates localization phenomenon in fermions to the rotational symmetry breaking in the critical spin chains. One of the intriguing consequence is that the statement of Onsager universality in spin chains implies universality of the localized fermions where the fluctuations in localized wave functions are universal. We further show that the fluctuations about localized nonrelativistic fermions describe relativistic fermions. This provides a new approach to understand the absence of localization in disordered Dirac fermions. We investigate how disorder affects well known universality of the spin chains by examining the multifractal exponents. Finally, we examine the effects of correlations on the localization characteristics of relativistic fermions.
Thermal stability study of transition metal perovskite sulfides

Transition metal perovskite chalcogenides, a class of materials with rich tunability in functionalities, are gaining increased attention as candidate materials for renewable energy applications. Perovskite oxides are considered excellent n-type thermoelectric materials. Compared to oxide counterparts, we expect the chalcogenides to possess more favorable thermoelectric properties such as lower lattice thermal conductivity and smaller band gap, making them promising material candidates for high temperature thermoelectrics. Thus, it is necessary to study the thermal properties of these materials in detail, especially thermal stability, to evaluate their potential. In this work, we report the synthesis and thermal stability study of five compounds, α-SrZrS3, β-SrZrS3, BaZrS3, Ba2ZrS4, and Ba3Zr2S7. These materials cover several structural types including distorted perovskite, needle-like, and Ruddlesden–Popper phases. Differential scanning calorimeter and thermogravimetric analysis measurements were performed up to 1200 °C in air. Structural and chemical characterizations such as X-ray diffraction, Raman spectroscopy, and energy dispersive analytical X-ray spectroscopy were performed on all the samples before and after the heat treatment to understand the oxidation process. Our studies show that perovskite chalcogenides possess excellent thermal stability in air at least up to 550 °C.
V409 TAU AS ANOTHER AA TAU: PHOTOMETRIC OBSERVATIONS OF STELLAR OCCULTATIONS BY THE CIRCUMSTELLAR DISK

AA Tau is a well studied young stellar object that presents many of the photometric characteristics of a Classical T Tauri star (CTTS), including short-timescale stochastic variability attributed to spots and/or accretion as well as long duration dimming events attributed to occultations by vertical features (e.g., warps) in its circumstellar disk. We present new photometric observations of AA Tau from the Kilodegree Extremely Little Telescope North (KELT-North) which reveal a deep, extended dimming event in 2011, which we show supports the interpretation by Bouvier et al. (2013) of an occultation by a high-density feature in the circumstellar disk located >8 AU from the star. We also present KELT-North observations of V409 Tau, a relatively unstudied young stellar object also in Taurus-Auriga, showing short timescale erratic variability, along with two separate long and deep dimming events, one from January 2009 through late October 2010, and the other from March 2012 until at least September 2013. We interpret both dimming events to have lasted more than 600 days, each with a depth of ~1.4 mag. From a spectral energy distribution analysis, we propose that V409 Tau is most likely surrounded by a circumstellar disk viewed nearly edge-on, and using Keplerian timescale arguments we interpret the deep dimmings of V409 Tau as occultations from one or more features within this disk >10 AU from the star. In both AA Tau and V409 Tau, the usual CTTS short-timescale variations associated with accretion processes close to the stars continue during the occultations, further supporting the distant occulting material interpretation. Like AA Tau, V409 Tau serves as a laboratory for studying the detailed structure of the protoplanetary environments of T Tauri disks, specifically disk structures that may be signposts of planet formation at many AU out in the disk.
Near-Optimal Distributed Band-Joins through Recursive Partitioning

We consider running-time optimization for band-joins in a distributed system, e.g., the cloud. To balance load across worker machines, input has to be partitioned, which causes duplication. We explore how to resolve this tension between maximum load per worker and input duplication for band-joins between two relations. Previous work suffered from high optimization cost or considered partitionings that were too restricted (resulting in suboptimal join performance). Our main insight is that recursive partitioning of the join-attribute space with the appropriate split scoring measure can achieve both low optimization cost and low join cost. It is the first approach that is not only effective for one-dimensional band-joins but also for joins on multiple attributes. Experiments indicate that our method is able to find partitionings that are within 10% of the lower bound for both maximum load per worker and input duplication for a broad range of settings, significantly improving over previous work.
Pauli-Villars Regularization of Non-Abelian Gauge Theories

As an extension of earlier work on QED, we construct a BRST-invariant Lagrangian for SU(N) Yang–Mills theory with fundamental matter, regulated by the inclusion of massive Pauli–Villars (PV) gluons and PV quarks. The underlying gauge symmetry for massless PV gluons is generalized to accommodate the PV-index-changing currents that are required by the regularization. Auxiliary adjoint scalars are used, in a mechanism due to Stueckelberg, to attribute mass to the PV gluons and the PV quarks. The addition of Faddeev–Popov ghosts then establishes a residual BRST symmetry. Although there are drawbacks to the approach, in particular the computational load of a large number of PV fields and a nonlocal interaction of the ghost fields, this formulation could provide a foundation for renormalizable nonperturbative solutions of light-front QCD in an arbitrary covariant gauge.
SIGNet: Scalable Embeddings for Signed Networks

Recent successes in word embedding and document embedding have motivated researchers to explore similar representations for networks and to use such representations for tasks such as edge prediction, node label prediction, and community detection. Such network embedding methods are largely focused on finding distributed representations for unsigned networks and are unable to discover embeddings that respect polarities inherent in edges. We propose SIGNet, a fast scalable embedding method suitable for signed networks. Our proposed objective function aims to carefully model the social structure implicit in signed networks by reinforcing the principles of social balance theory. Our method builds upon the traditional word2vec family of embedding approaches and adds a new targeted node sampling strategy to maintain structural balance in higher-order neighborhoods. We demonstrate the superiority of SIGNet over state-of-the-art methods proposed for both signed and unsigned networks on several real world datasets from different domains. In particular, SIGNet offers an approach to generate a richer vocabulary of features of signed networks to support representation and reasoning.
Coherent production of pairs of parabosons of order 2

A parameter-free statistical model is used to study multiplicity signatures for coherent production of charged pairs of parabosons of order p = 2 in comparison with those arising in the case of ordinary bosons, p = 1. Two non-negative real parameters arise because “ab” and “ba” are fundamentally distinct pair operators of charge “ + 1”, A-quanta and charge “-1”, B-quanta parabosons. In 3D plots of ${P_{m}}(q)\equiv$ “the probability of m paraboson charged pairs + q positive parabosons” versus $\langle n\rangle $ and $\langle n^2\rangle $ , the p = 1 curve is found to lie on the relatively narrow 2D p = 2 surface.
COUPLING CONSTANT UNIFICATION IN EXTENSIONS OF STANDARD MODEL

Unification of electromagnetic, weak, and strong coupling constants is studied in the extension of Standard Model with additional fermions and scalars. It is remarkable that this unification in the supersymmetric extension of Standard Model yields a value of Weinberg angle which agrees very well with experiments. We discuss the other possibilities which can also give same result.
Computational Eulerian hydrodynamics and Galilean invariance

Eulerian hydrodynamical simulations are a powerful and popular tool for modelling fluids in astrophysical systems. In this work, we critically examine recent claims that these methods violate Galilean invariance of the Euler equations. We demonstrate that Eulerian hydrodynamics methods do converge to a Galilean-invariant solution, provided a well-defined convergent solution exists. Specifically, we show that numerical diffusion, resulting from diffusion-like terms in the discretized hydrodynamical equations solved by Eulerian methods, accounts for the effects previously identified as evidence for the Galilean non-invariance of these methods. These velocity-dependent diffusive terms lead to different results for different bulk velocities when the spatial resolution of the simulation is kept fixed, but their effect becomes negligible as the resolution of the simulation is increased to obtain a converged solution. In particular, we find that Kelvin–Helmholtz instabilities develop properly in realistic Eulerian calculations regardless of the bulk velocity provided the problem is simulated with sufficient resolution (a factor of 2–4 increase compared to the case without bulk flows for realistic velocities). Our results reiterate that high-resolution Eulerian methods can perform well and obtain a convergent solution, even in the presence of highly supersonic bulk flows.
MERIDIONAL CIRCULATION IN SOLAR AND STELLAR CONVECTION ZONES

We present a series of 3D nonlinear simulations of solar-like convection, carried out using the Anelastic Spherical Harmonic code, that are designed to isolate those processes that drive and shape meridional circulations (MCs) within stellar convection zones. These simulations have been constructed so as to span the transition between solar-like differential rotation (DR; fast equator/slow poles) and “anti-solar” DR (slow equator/fast poles). Solar-like states of DR, which arise when convection is rotationally constrained, are characterized by a very different convective Reynolds stress (RS) than anti-solar regimes, wherein convection only weakly senses the Coriolis force. We find that the angular momentum transport by convective RS plays a central role in establishing the meridional flow profiles in these simulations. We find that the transition from single-celled to multi-celled MC profiles in strong and weak regimes of rotational constraint is linked to a change in the convective RS, which is a clear demonstration of gyroscopic pumping. Latitudinal thermal variations differ between these different regimes, with those in the solar-like regime conspiring to suppress a single cell of MC, whereas the cool poles and warm equator established in the anti-solar states tend to promote single-celled circulations. Although the convective angular momentum transport becomes radially inward at mid-latitudes in anti-solar regimes, it is the MC that is primarily responsible for establishing a rapidly rotating pole. We conclude with a discussion of how these results relate to the Sun, and suggest that the Sun may lie near the transition between rapidly rotating and slowly rotating regimes.
Star Formation During Galaxy Formation

Young galaxies are clumpy, gas-rich, and highly turbulent. Star formation appears to occur by gravitational instabilities in galactic disks. The high dispersion makes the clumps massive and the disks thick. The star formation rate should be comparable to the gas accretion rate of the whole galaxy, because star formation is usually rapid and the gas would be depleted quickly otherwise. The empirical laws for star formation found locally hold at redshifts around 2, although the molecular gas consumption time appears to be smaller, and mergers appear to form stars with a slightly higher efficiency than the majority of disk galaxies.
Power sum decompositions of defining equations of reflection arrangements

We determine the Waring rank and a Waring decomposition of the fundamental skew invariant of any complex reflection group whose highest degree is a regular number. This includes all irreducible real reflection groups.
Activity From Tidal Disruptions in Galactic Nuclei

The tidal disruption of a star by a supermassive black hole is expected to lead to a short bright flare followed by an extended period of low-level emission. Existing models of the late-time accretion of the stellar debris via a thin disk imply that the Galactic center source Sgr A* should be brighter than currently observed by several orders of magnitude. A similar problem exists for M31 and M32. This problem could be avoided if thin disk accretion transitions to low radiative efficiency accretion (e.g., advection-dominated or convection-dominated accretion flows) at low accretion rates (via "evaporation" of the thin disk). Alternatively, we show that the outer portions of a thin disk may become neutral and unable to sustain MHD turbulence on a timescale of less than the time between tidal disruption events; this may dramatically shorten the duration of the late accretion phase.
Short-range correlations and their implications for isospin-dependent modification of nuclear quark distributions

The past decade has provided a much clearer picture of the structure of high-momentum components in nucleons, associated with hard, short-distance interactions between pairs of nucleons. Recent Jefferson Lab data on light nuclei suggest a connection between these so-called ’short-range correlations’ and the modification of the quark structure of nucleons in the nuclear environment. In light of this discovery that the detailed nuclear structure is important in describing the nuclear quark distributions, we examine the potential impact of the isospin-dependent structure of nuclei to see at what level this might yield flavor-dependent effects in nuclear quark distributions.
Comments on one-form global symmetries and their gauging in 3d and 4d

We study 3d and 4d systems with a one-form global symmetry, explore theirconsequences, and analyze their gauging. For simplicity, we focus on$\mathbb{Z}_N$ one-form symmetries. A 3d topological quantum field theory(TQFT) $\mathcal{T}$ with such a symmetry has $N$ special lines that generateit. The braiding of these lines and their spins are characterized by a singleinteger $p$ modulo $2N$. Surprisingly, if $\gcd(N,p)=1$ the TQFT factorizes$\mathcal{T}=\mathcal{T}'\otimes \mathcal{A}^{N,p}$. Here $\mathcal{T}'$ is adecoupled TQFT, whose lines are neutral under the global symmetry and$\mathcal{A}^{N,p}$ is a minimal TQFT with the $\mathbb{Z}_N$ one-form symmetryof label $p$. The parameter $p$ labels the obstruction to gauging the$\mathbb{Z}_N$ one-form symmetry; i.e.\ it characterizes the 't Hooft anomalyof the global symmetry. When $p=0$ mod $2N$, the symmetry can be gauged.Otherwise, it cannot be gauged unless we couple the system to a 4d bulk withgauge fields extended to the bulk. This understanding allows us to consider$SU(N)$ and $PSU(N)$ 4d gauge theories. Their dynamics is gapped and it isassociated with confinement and oblique confinement -- probe quarks areconfined. In the $PSU(N)$ theory the low-energy theory can include a discretegauge theory. We will study the behavior of the theory with a space-dependent$\theta$-parameter, which leads to interfaces. Typically, the theory on theinterface is not confining. Furthermore, the liberated probe quarks are anyonson the interface. The $PSU(N)$ theory is obtained by gauging the $\mathbb{Z}_N$one-form symmetry of the $SU(N)$ theory. Our understanding of the symmetries in3d TQFTs allows us to describe the interface in the $PSU(N)$ theory.
Inflation expels runaways

We argue that moduli stabilization generically restricts the evolution following transitions between weakly coupled de Sitter vacua and can induce a strong selection bias towards inflationary cosmologies. The energy density of domain walls between vacua typically destabilizes Kahler moduli and triggers a runaway towards large volume. This decompactification phase can collapse the new de Sitter region unless a minimum amount of inflation occurs after the transition. A stable vacuum transition is guaranteed only if the inflationary expansion generates overlapping past light cones for all observable modes originating from the reheating surface, which leads to an approximately flat and isotropic universe. High scale inflation is vastly favored. Our results point towards a framework for studying parameter fine-tuning and inflationary initial conditions in flux compactifications.
Extending Expected Improvement for High-Dimensional Stochastic Optimization of Expensive Black-Box Functions

Design optimization under uncertainty is notoriously difficult when the objective function is expensive to evaluate. State-of-the-art techniques, e.g, stochastic optimization or sampling average approximation, fail to learn exploitable patterns from collected data and require an excessive number of objective function evaluations. There is a need for techniques that alleviate the high cost of information acquisition and select sequential simulations optimally. In the field of deterministic single-objective unconstrained global optimization, the Bayesian global optimization (BGO) approach has been relatively successful in addressing the information acquisition problem. BGO builds a probabilistic surrogate of the expensive objective function and uses it to define an information acquisition function (IAF) whose role is to quantify the merit of making new objective evaluations. Specifically, BGO iterates between making the observations with the largest expected IAF and rebuilding the probabilistic surrogate, until a convergence criterion is met. In this work, we extend the expected improvement (EI) IAF to the case of design optimization under uncertainty wherein the EI policy is reformulated to filter out parametric and measurement uncertainties. To increase the robustness of our approach in the low sample regime, we employ a fully Bayesian interpretation of Gaussian processes by constructing a particle approximation of the posterior of its hyperparameters using adaptive Markov chain Monte Carlo. We verify and validate our approach by solving two synthetic optimization problems under uncertainty and demonstrate it by solving the oil-well-placement problem with uncertainties in the permeability field and the oil price time series.
Preliminary Results from Integrating Compton Photon Polarimetry in Hall A of Jefferson Lab

A wide range of nucleon and nuclear structure experiments in Jefferson Lab's Hall A require precise, continuous measurements of the polarization of the electron beam. In our Compton polarimeter, electrons are scattered off photons in a Fabry-Perot cavity; by measuring an asymmetry in the integrated signal of the scattered photons detected in a GSO crystal, we can make non-invasive, continuous measurements of the beam polarization. Our goal is to achieve 1% statistical error within two hours of running. We discuss the design and commissioning of an upgrade to this apparatus, and report preliminary results for experiments conducted at beam energies from 3.5 to 5.9 GeV and photon rates from 5 to 100 kHz.
Distributive Dynamic Spectrum Access Through Deep Reinforcement Learning: A Reservoir Computing-Based Approach

Dynamic spectrum access (DSA) is regarded as an effective and efficient technology to share radio spectrum among different networks. As a secondary user (SU), a DSA device will face two critical problems: 1) avoiding causing harmful interference to primary users (PUs) and 2) conducting effective interference coordination with other SUs. These two problems become even more challenging for a distributed DSA network where there is no centralized controllers for SUs. In this paper, we investigate communication strategies of a distributive DSA network under the presence of spectrum sensing errors. To be specific, we apply the powerful machine learning tool, deep reinforcement learning (DRL), for SUs to learn “appropriate” spectrum access strategies in a distributed fashion assuming NO knowledge of the underlying system statistics. Furthermore, a special type of recurrent neural network, called the reservoir computing (RC), is utilized to realize DRL by taking advantage of the underlying temporal correlation of the DSA network. Using the introduced machine learning-based strategy, SUs could make spectrum access decisions distributedly relying only on their own current and past spectrum sensing outcomes. Through extensive experiments, our results suggest that the RC-based spectrum access strategy can help the SU to significantly reduce the chances of collision with PUs and other SUs. We also show that our scheme outperforms the myopic method which assumes the knowledge of system statistics, and converges faster than the Q -learning method when the number of channels is large.
Anti-de Sitter black holes in gauged N = 8 supergravity

We present new anti-de Sitter black hole solutions of gauged N = 8, SO(8) supergravity, which is the massless sector of the AdS4 × S70 vacuum of M-theory. By focusing on the U(1)4 Cartan subgroup, we find non-extremal 1, 2, 3 and 4 charge solutions. In the extremal limit, they may preserve up to 12, 14, 18 and 18 of the supersymmetry, respectively. In the limit of vanishing SO(8) coupling constant, the solutions reduce to the familiar black holes of the M4 × T7 vacuum, but have very different interpretation since there are no winding states on S7 and no U-duality. In contrast to the T7 compactification, moreover, we find no static multi-center solutions. Also in contrast, the S7 fields appear “already dualized” so that the 4 charges may be all electric or all magnetic rather than 2 electric and 2 magnetic. Curiously, however, the magnetic solutions preserve no supersymmetries. We conjecture that a subset of the extreme electric black holes preserving 12 the supersymmetry may be identified with the S7 Kaluza-Klein spectrum, with the non-abelian SO(8) quantum numbers provided by the fermionic zero-modes.
Periodic Fast Radio Bursts from Young Neutron Stars

Fast radio bursts (FRBs) are highly energetic radio pulses from cosmological origins. Despite an abundance of detections, their nature remains elusive. At least a subset of FRBs is expected to repeat, as the daily FRB rate surpasses that of any known cataclysmic event, which has been confirmed by observations. One of the proposed mechanisms to generate repeating FRBs is supergiant pulses from young and highly spinning NSs, in which case FRBs could inherit the periodicity of their parent NS. Here we examine the consequences of such a population of periodic fast radio bursts (PFRBs). We calculate the rate and lifetime of PFRB progenitors, and find that each newly born highly spinning NS has to emit a number $N_{\rm PFRB}\sim 10^2$ of bursts during its active lifetime of $\tau\sim 100$ years, after which it becomes too dim and crosses a PFRB "death line" analogous to the pulsar one. We propose several tests of this hypothesis. First, the period of PFRBs would increase over time, and their luminosity would decrease, due to the NS spin-down. Second, PFRBs may show modest amounts of rotation measure, given the lack of expelled matter from the pulsar, as opposed to the magnetar-sourced FRBs proposed to explain the first repeater FRB 121102. As an example, we study whether the second confirmed repeater (FRB 180814) is a PFRB, given the preference for an inter-pulse separation of 13 ms within its sub-bursts. We show that, if confirmed, this period would place FRB 180814 in a different category as FRB 121102. We develop tests that would identify---and characterize---the prospective population of PFRBs.
On the analyticity and Gevrey-class regularity up to the boundary for the Euler equations

We consider the Euler equations in a three-dimensional Gevrey-class bounded domain. Using Lagrangian coordinates we obtain the Gevrey-class persistence of the solution, up to the boundary, with an explicit estimate on the rate of decay of the Gevrey-class regularity radius, in terms of Sobolev norms.
Building massive compact planetesimal disks from the accretion of pebbles

We present a model in which planetesimal disks are built from the combination of planetesimal formation and the accretion of radially drifting pebbles onto existing planetesimals. In this model, the rate of accretion of pebbles onto planetesimals quickly outpaces the rate of direct planetesimal formation in the inner disk. This allows for the formation of a high-mass inner disk without the need for enhanced planetesimal formation or a massive protoplanetary disk. Our proposed mechanism for planetesimal disk growth does not require any special conditions to operate. Consequently, we expect high-mass planetesimal disks to form naturally in nearly all systems. The extent of this growth is controlled by the total mass in pebbles that drifts through the inner disk. Anything that reduces the rate or duration of pebble delivery will correspondingly reduce the final mass of the planetesimal disk. Therefore, we expect low-mass stars (with less massive protoplanetary disks), low-metallicity stars, and stars with giant planets to grow less massive planetesimal disks. The evolution of planetesimal disks into planetary systems remains a mystery. However, we argue that late stage planet formation models should begin with a massive disk. This reinforces the idea that massive and compact planetary systems could form in situ, but does not exclude the possibility that significant migration occurs post-planet formation.
Environmentally Induced Exceptional Points in Elastodynamics

We study the nature of an environment-induced exceptional point in a non-Hermitian pair of coupled mechanical oscillators. The mechanical oscillators are a pair of pillars carved out of a single isotropic elastodynamic medium made of aluminum and consist of carefully controlled differential losses. The interoscillator coupling originates exclusively from background modes associated with the ``environment,'' that portion of the structure which, if perfectly rigid, would support the oscillators without coupling. We describe the effective interaction in terms of a coupled-mode framework in which only one nearby environmental mode can qualitatively reproduce changes to the exceptional-point characteristics. Our experimental and numerical demonstrations illustrate strategic directions utilizing environmental mode control for the implementation of exceptional-point degeneracies. Potential applications include a new type of noninvasive differential atomic force microscopy and hypersensitive sensors for the structural integrity of surfaces.
Transport phenomena in stochastic magnetic mirrors

Parallel thermal conduction along stochastic magnetic field lines may be reduced because the heat-conducting electrons become trapped and detrapped between regions of strong magnetic field (magnetic mirrors). The problem reduces to a simple but realistic model for diffusion of monoenergetic electrons based on the fact that when there is a reduction of diffusion, it is controlled by a subset of the mirrors, the principal mirrors. The diffusion reduction can be considered as equivalent to an enhancement of the pitch angle scattering rate. Therefore, in deriving the collision integral, we modify the pitch angle scattering term. We take into account the full perturbed electron-electron collision integral, as well as the electron-proton collision term. Finally, we obtain the four plasma transport coefficients and the effective thermal conductivity. We express them as reductions from the classical values. We present these reductions as functions of the ratio of the magnetic field decorrelation length to the electron mean free path at the thermal speed VT = 1/2. We briefly discuss an application of our results to clusters of galaxies.
Eulerian cube complexes and reciprocity

that G admits a suitable automatic structure, Gx.t/ can be shown to be a rational function. We prove that if Y is a manifold of dimension n, then this rational function satisfies the reciprocity formula Gx.t 1 /D. 1/ n Gx.t/. We prove the formula in a more general setting, replacing the group with the fundamental groupoid, replacing the growth series with the characteristic series for a suitable regular language, and only assuming Y is Eulerian. 20F55; 20F10, 05A15
Indecomposable Ideals in Incidence Algebras

The elements of a finite partial order P can be identified with the maximal indecomposable two-sided ideals of its incidence algebra , and then for two such ideals, I ≺ J ⇔ IJ ≠ 0. This offers one way to recover a poset from its incidence algebra. In the course of proving the above, we classify all of the two-sided ideals of .
Existence of Rotating Planet Solutions to the Euler–Poisson Equations with an Inner Hard Core

The Euler–Poisson equations model rotating gaseous stars. Numerous efforts have been made to establish the existence and properties of the rotating star solutions. Recent interests in extrasolar planet structures require extension of the model to include an inner rocky core together with its own gravitational potential. In this paper, we discuss various extensions of the classical rotating star results to incorporate a solid core.
Fast Charge Sensing of a Cavity-Coupled Double Quantum Dot Using a Josephson Parametric Amplifier

Double quantum dots (DQDs), sometimes referred to as ``artificial molecules'', are highly controllable quantum systems that serve as building blocks for spin-based quantum computation. A fast, high-fidelity charge sensor is needed for determining the number of electrons trapped in the DQD, and for spin-state readout. Here the authors integrate a Josephson parametric amplifier into the readout chain, improving the signal to noise ratio by a factor of 2000 and enabling live tuning of the DQD potential well, without the slow, painstaking adjustment of voltages on several electrodes.
An application of survival analysis to disruption prediction via Random Forests

One of the most pressing challenges facing the fusion community is adequately mitigating or, even better, avoiding disruptions of tokamak plasmas. However, before this can be done, disruptions must first be predicted with sufficient warning time to actuate a response. The established field of survival analysis provides a convenient statistical framework for time-to-event (i.e. time-to-disruption) studies. This paper demonstrates the integration of an existing disruption prediction machine learning algorithm with the Kaplan-Meier estimator of survival probability. Specifically discussed are the implied warning times from binary classification of disruption databases and the interpretation of output signals from Random Forest algorithms trained and tested on these databases. This survival analysis approach is applied to both smooth and noisy test data to highlight important features of the survival and hazard functions. In addition, this method is applied to three Alcator C-Mod plasma discharges and compared to a threshold-based scheme for triggering alarms. In one case, both techniques successfully predict the disruption; although, in another, neither warns of the impending disruption with enough time to mitigate. For the final discharge, the survival analysis approach could avoid the false alarm triggered by the threshold method. Limitations of this analysis and opportunities for future work are also presented.