cssi/SciSciGPT-SciSciNet huggingface dataset:
Parameter Estimation in Gaussian Mixture Models with Malicious Noise, without Balanced Mixing Coefficients

We consider the problem of estimating the means of components in a noisy 2-Gaussian Mixture Model (2-GMM) without balanced weights, where the noise is of an arbitrary distribution. We present a robust algorithm to estimate the parameters, together with upper bounds on the numbers of samples required for the good estimates, where the bounds are parametrised by the dimension, ratio of the mixing coefficients, the separation of the two Gaussians in terms of Mahalanobis distance, and a condition number of the covariance matrix. In theory, this is the first sample-complexity result for Gaussian mixtures corrupted by adversarial noise. In practice, our algorithm outperforms the vanilla Expectation-Maximisation (EM) algorithm by orders of magnitude in terms of estimation error.
Exact Localization and Superresolution with Noisy Data and Random Illumination

This paper studies the problem of exact localization of multiple objects with noisy data. The crux of the proposed approach consists of random illumination. Two recovery methods are analyzed: the Lasso and the one-step thresholding (OST). For independent random probes, it is shown that both recovery methods can localize exactly , up to a logarithmic factor, objects where m is the number of data. Moreover, when the number of random probes is large the Lasso with random illumination has a performance guarantee for superresolution, beating the Rayleigh resolution limit. Numerical evidence confirms the predictions and indicates that the performance of the Lasso is superior to that of the OST for the proposed setup with random illumination.
COMMENTS ON BRANE WORLD COSMOLOGY

In this letter we consider some constraints on brane-world cosmologies. In the first part we analyze different behaviors for the expansion of our universe by imposing constraints on the speed of sound. In the second part, we study the nature of matter on the brane world by means of the well-known energy conditions. We find that the strong energy condition must be completely violated at late stages of the universe.
A Turing test for free will

Before Alan Turing made his crucial contributions to the theory of computation, he studied the question of whether quantum mechanics could throw light on the nature of free will. This paper investigates the roles of quantum mechanics and computation in free will. Although quantum mechanics implies that events are intrinsically unpredictable, the 'pure stochasticity' of quantum mechanics adds randomness only to decision-making processes, not freedom. By contrast, the theory of computation implies that, even when our decisions arise from a completely deterministic decision-making process, the outcomes of that process can be intrinsically unpredictable, even to-especially to-ourselves. I argue that this intrinsic computational unpredictability of the decision-making process is what gives rise to our impression that we possess free will. Finally, I propose a 'Turing test' for free will: a decision-maker who passes this test will tend to believe that he, she, or it possesses free will, whether the world is deterministic or not.
Quantum Data Hiding in the Presence of Noise

When classical or quantum information is broadcast to separate receivers, there exist codes that encrypt the encoded data, such that the receivers cannot recover it when performing local operations and classical communication, but they can reliably decode if they bring their systems together and perform a collective measurement. This phenomenon is known as quantum data hiding and hitherto has been studied under the assumption that noise does not affect the encoded systems. With the aim of applying the quantum data hiding effect in practical scenarios, here, we define the data-hiding capacity for hiding classical information using a quantum channel. Using this notion, we establish a regularized upper bound on the data hiding capacity of any quantum broadcast channel, and we prove that coherent-state encodings have a strong limitation on their data hiding rates. We, then, prove a lower bound on the data hiding capacity of channels that map the maximally mixed state to the maximally mixed state (we call these channels mictodiactic—they can be seen as a generalization of unital channels when the input and output spaces are not necessarily isomorphic) and argue how to extend this bound to generic channels and to more than two receivers.
Demonstration of an electric field conjugation algorithm for improved starlight rejection through a single mode optical fiber

Linking a coronagraph instrument to a spectrograph via a single-mode optical fiber is a pathway toward detailed characterization of exoplanet atmospheres with current and future ground- and space-based telescopes. However, given the extreme brightness ratio and small angular separation between planets and their host stars, the planet signal-to-noise ratio will likely be limited by the unwanted coupling of starlight into the fiber. To address this issue, we utilize a wavefront control loop and a deformable mirror to systematically reject starlight from the fiber by measuring what is transmitted through the fiber. The wavefront control algorithm is based on the formalism of electric field conjugation (EFC), which in our case accounts for the spatial mode selectivity of the fiber. This is achieved by using a control output that is the overlap integral of the electric field with the fundamental mode of a single-mode fiber. This quantity can be estimated by pairwise image plane probes injected using a deformable mirror. We present simulation and laboratory results that demonstrate our approach offers a significant improvement in starlight suppression through the fiber relative to a conventional EFC controller. With our experimental setup, which provides an initial normalized intensity of 3 × 10 − 4 in the fiber at an angular separation of 4λ / D , we obtain a final normalized intensity of 3 × 10 − 6 in monochromatic light at λ = 635 nm through the fiber (100 × suppression factor) and 2 × 10 − 5 in Δλ / λ = 8 % broadband light about λ = 625 nm (10 × suppression factor). The fiber-based approach improves the sensitivity of spectral measurements at high contrast and may serve as an integral part of future space-based exoplanet imaging missions as well as ground-based instruments.
Phase-coherent detection of an optical dipole force by Doppler velocimetry.

We report phase-coherent Doppler detection of optical dipole forces using large ion crystals in a Penning trap. The technique is based on laser Doppler velocimetry using a cycling transition in 9Be+ near 313 nm and the center-of-mass (COM) ion motional mode. The optical dipole force is tuned to excite the COM mode, and measurements of photon arrival times synchronized with the excitation potential show oscillations with a period commensurate with the COM motional frequency. Experimental results compare well with a quantitative model for a driven harmonic oscillator. This technique permits characterization of motional modes in ion crystals; the measurement of both frequency and phase information relative to the driving force is a key enabling capability – comparable to lockin detection – providing access to a parameter that is typically not available in time-averaged measurements. This additional information facilitates discrimination of nearly degenerate motional modes.
Large $N$ expansion of the moments and free energy of Sachdev-Ye-Kitaev model, and the enumeration of intersection graphs

In this paper we explain the relation between the free energy of the SYK model for N Majorana fermions with a random q-body interaction and the moments of its spectral density. The high temperature expansion of the free energy gives the cumulants of the spectral density. Using that the cumulants are extensive we find the p dependence of the 1/N2 correction of the 2p-th moments obtained in [1]. Conversely, the 1/N2 corrections to the moments give the correction (even q) to the β6 coefficient of the high temperature expansion of the free energy for arbitrary q. Our result agrees with the 1/q3 correction obtained by Tarnopolsky using a mean field expansion. These considerations also lead to a more powerful method for solving the moment problem and intersection-graph enumeration problems. We take advantage of this and push the moment calculation to 1/N3 order and find surprisingly simple enumeration identities for intersection graphs. The 1/N3 corrections to the moments, give corrections to the β8 coefficient (for even q) of the high temperature expansion of the free energy which have not been calculated before. Results for odd q, where the SYK “Hamiltonian” is the supercharge of a supersymmetric theory are discussed as well.
The binary black hole explorer: on-the-fly visualizations of precessing binary black holes

Binary black hole mergers are of great interest to the astrophysics community, not least because of their promise to test general relativity in the highly dynamic, strong field regime. Detections of gravitational waves from these sources by LIGO and Virgo have garnered widespread media and public attention. Among these sources, precessing systems (with misaligned black-hole spin/orbital angular momentum) are of particular interest because of the rich dynamics they offer. However, these systems are, in turn, more complex compared to nonprecessing systems, making them harder to model or develop intuition about. Visualizations of numerical simulations of precessing systems provide a means to understand and gain insights about these systems. However, since these simulations are very expensive, they can only be performed at a small number of points in parameter space. We present binaryBHexp, a tool that makes use of surrogate models of numerical simulations to generate on-the-fly interactive visualizations of precessing binary black holes. These visualizations can be generated in a few seconds, and at any point in the 7-dimensional parameter space of the underlying surrogate models. With illustrative examples, we demonstrate how this tool can be used to learn about precessing binary black hole systems.
Bubble cloud dynamics in an ultrasound field

The dynamics of bubble clouds induced by high-intensity focused ultrasound is investigated in a regime where the cloud size is similar to the ultrasound wavelength. High-speed images show that the cloud is asymmetric; the bubbles nearest the source grow to a larger radius than the distal ones. Similar structures of bubble clouds are observed in numerical simulations that mimic the laboratory experiment. To elucidate the structure, a parametric study is conducted for plane ultrasound waves with various amplitudes and diffuse clouds with different initial void fractions. Based on an analysis of the kinetic energy of liquid induced by bubble oscillations, a new scaling parameter is introduced to characterize the dynamics. The new parameter generalizes the cloud interaction parameter originally introduced by d’Agostino & Brennen (J. Fluid Mech., vol. 199, 1989, pp. 155–176). The dynamic interaction parameter controls the energy localization and consequent anisotropy of the cloud. Moreover, the amplitude of the far-field, bubble-scattered acoustics is likewise correlated with the proposed parameter. Findings of the present study not only shed light on the physics of cloud cavitation, but may also be of use for the quantification of the effects of cavitation on outcomes of ultrasound therapies including high-intensity focused ultrasound-based lithotripsy.
HPX Smart Executors

The performance of many parallel applications depends on loop-level parallelism. However, manually parallelizing all loops may result in degrading parallel performance, as some of them cannot scale desirably to a large number of threads. In addition, the overheads of manually tuning loop parameters might prevent an application from reaching its maximum parallel performance. We illustrate how machine learning techniques can be applied to address these challenges. In this research, we develop a framework that is able to automatically capture the static and dynamic information of a loop. Moreover, we advocate a novel method by introducing HPX smart executors for determining the execution policy, chunk size, and prefetching distance of an HPX loop to achieve higher possible performance by feeding static information captured during compilation and runtime-based dynamic information to our learning model. Our evaluated execution results show that using these smart executors can speed up the HPX execution process by around 12% -- 35% for the Matrix Multiplication, Stream and 2D Stencil benchmarks compared to setting their HPX loop's execution policy/parameters manually or using HPX auto-parallelization techniques.
Interstellar and ejecta dust in the cas a supernova remnant

The ejecta of the Cas A supernova remnant has a complex morphology, consisting of dense fast-moving line emitting knots and diffuse X-ray emitting regions that have encountered the reverse shock, as well as more slowly expanding, unshocked regions of the ejecta. Using the Spitzer 5-35 micron IRS data cube, and Herschel 70, 100, and 160 micron PACS data, we decompose the infrared emission from the remnant into distinct spectral components associated with the different regions of the ejecta. Such decomposition allows the association of different dust species with ejecta layers that underwent distinct nuclear burning histories, and determination of the dust heating mechanisms. Our decomposition identified three characteristic dust spectra. The first, most luminous one, exhibits strong emission features at approx. 9 and 21 micron, and a weaker 12 micron feature, and is closely associated with the ejecta knots that have strong [Ar II] 6.99 micron and [Ar III] 8.99 micron emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low MgO-to-SiO2 ratios. A second, very different dust spectrum that has no indication of any silicate features, is best fit by Al2O3 dust and is found in association with ejecta having strong [Ne II] 12.8 micron and [Ne III] 15.6 micron emission lines. A third characteristic dust spectrum shows features that best matched by magnesium silicates with relatively high MgO-to-SiO2 ratio. This dust is primarily associated with the X-ray emitting shocked ejecta and the shocked interstellar/circumstellar material. All three spectral components include an additional featureless cold dust component of unknown composition. Colder dust of indeterminate composition is associated with [Si II] 34.8 micron emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. The dust mass giving rise to the warm dust component is about approx. 0.1solar M. However, most of the dust mass is associated with the unidentified cold dust component. Its mass could be anywhere between 0.1 and 1 solar M, and is primarily limited by the mass of refractory elements in the ejecta. Given the large uncertainty in the dust mass, the question of whether supernovae can produce enough dust to account for ISM dust masses in the local and high-z universe remains largely unresolved.
On performance stability in LSM-based storage systems

The Log-Structured Merge-Tree (LSM-tree) has been widely adopted for use in modern NoSQL systems for its superior write performance. Despite the popularity of LSM-trees, they have been criticized for suffering from write stalls and large performance variances due to the inherent mismatch between their fast in-memory writes and slow background I/O operations. In this paper, we use a simple yet effective two-phase experimental approach to evaluate write stalls for various LSM-tree designs. We further identify and explore the design choices of LSM merge schedulers to minimize write stalls given an I/O bandwidth budget. We have conducted extensive experiments in the context of the Apache AsterixDB system and we present the results here.
A SEARCH FOR RR LYRAE STARS IN SEGUE 2 AND SEGUE 3

We present an extensive search for RR Lyrae (RRL) stars in and around the ultra-faint Milky Way companions Segue?2 and Segue?3. The former (MV = ?2.5) appears to be an extremely faint dwarf galaxy companion of the Milky Way. The latter (MV = 0.0) is among the faintest star clusters known. We use B and V band time-series imaging obtained at the WIYN 0.9?m telescope at Kitt Peak National Observatory to search for RRL in these objects. In our Segue?2 observations, we present a previously unknown fundamental mode (RRab) RRL star with a period of P ab = 0.748 days. With this measurement, we revisit the inverse correlation between P ab and [Fe/H] established in the literature for Milky Way dwarf galaxies and their RRL. In this context, the long period of Segue?2's RRab star as well as the known significant spread in metallicity in this dwarf galaxy are consistent with the observed trend in P ab and [Fe/H]. We derive the first robust distance to Segue?2, using both its RRab star and spectroscopically confirmed blue horizontal branch stars. Using [Fe/H] = ?2.16 and ?2.44 dex, we find and ?kpc; assuming [Fe/H] = ?2.257 dex, we find d BHB = 34.4 ? 2.6?kpc. Although no RRL were present in the Segue?3 field, we found a candidate eclipsing binary star system.
The canonical embedding of an unramified morphism in an étale morphism

We show that every unramified morphism XY has a canonical and universal factorization XEY where the first morphism is a closed embedding and the second is etale (but not separated).
Charmed baryon masses in chiral perturbation theory

Abstract The masses of the charmed baryons in the 6 representation of SU(3) obey an equal spacing rule at lowest order in SU(3) breaking, O (ms). We compute the corrections to this relation at order at order O (m s 3 2 ) arising from meson loops using chiral perturbation theory combined with heavy quark symmetry and find them to be small. We also examine the hyperfine interaction responsible for the splitting between the J π = 3 + 2 and J π = 1 + 2 baryons in the 6 representation. The results also hold in the b-baryon sector.
Poking the Beehive from Space: K2 Rotation Periods for Praesepe

We analyze {\it K2} light curves for 794 low-mass ($1 > M_* > 0.1$ $M_{\odot}$) members of the $\approx$650-Myr-old open cluster Praesepe, and measure rotation periods ($P_{rot}$) for 677 of these stars. We find that half of the rapidly rotating $>$0.3 $M_{\odot}$ stars are confirmed or candidate binary systems. The remaining $>0.3$ $M_{\odot}$ fast rotators have not been searched for companions, and are therefore not confirmed single stars. We found previously that nearly all rapidly rotating $>$0.3 $M_{\odot}$ stars in the Hyades are binaries, but we require deeper binary searches in Praesepe to confirm whether binaries in these two co-eval clusters have different $P_{rot}$ distributions. We also compare the observed $P_{rot}$ distribution in Praesepe to that predicted by models of angular-momentum evolution. We do not observe the clear bimodal $P_{rot}$ distribution predicted by Brown (2014) for $>$0.5 $M_{\odot}$ stars at the age of Praesepe, but 0.25$-$0.5 $M_{\odot}$ stars do show stronger bimodality. In addition, we find that $>$60\% of early M dwarfs in Praesepe rotate more slowly than predicted at 650 Myr by Matt et al. (2015), which suggests an increase in braking efficiency for these stars relative to solar-type stars and fully convective stars. The incompleteness of surveys for binaries in open clusters likely impacts our comparison with these models, since the models only attempt to describe the evolution of isolated single stars.
Compact Nuclei in Galaxies at Moderate Redshift. I. Imaging and Spectroscopy

This study explores the space density and properties of active galaxies to z0.8. We have investigated the frequency and nature of unresolved nuclei in galaxies at moderate redshift as indicators of nuclear activity such as active galactic nuclei (AGNs) or starbursts. Candidates are selected by fitting imaged galaxies with multicomponent models using maximum likelihood estimate techniques to determine the best model fit. We select those galaxies requiring an unresolved, point-source component in the galaxy nucleus, in addition to a disk and/or bulge component, to adequately model the galaxy light. We have searched 70 WFPC2 images primarily from the Medium Deep Survey for galaxies containing compact nuclei. In our survey of 1033 galaxies, the fraction containing an unresolved nuclear component ≥3% of the total galaxy light is 16%±3% corrected for incompleteness and 9%±1% for nuclei ≥5% of the galaxy light. Spectroscopic redshifts have been obtained for 35 of our AGN/starburst candidates, and photometric redshifts are estimated to an accuracy of σz 0.1 for the remaining sample. In this paper, the first of two for this study, we present the selected Hubble Space Telescope imaged galaxies having unresolved nuclei and discuss the selection procedure. We also present the ground-based spectroscopy for these galaxies as well as the photometric redshift predictions for those galaxies without spectra.
Dualities versus singularities

We show that a subgroup of the modular group of M-theory compactified on a ten torus, implies the Lorentzian structure of the moduli space, that is usually associated with naive discussions of quantum cosmology based on the low energy Einstein action. This structure implies a natural division of the asymptotic domains of the moduli space into regions which can/cannot be mapped to Type II string theory or 11D Supergravity (SUGRA) with large radii. We call these the safe and unsafe domains. The safe domain is the interior of the future light cone in the moduli space while the unsafe domain contains the spacelike region and the past light cone. Within the safe domain, apparent cosmological singularities can be resolved by duality transformations and we briefly provide a physical picture of how this occurs. The unsafe domains represent true singularities where all field theoretic description of the physics breaks down. They violate the holographic principle. We argue that this structure provides a natural arrow of time for cosmology. All of the Kasner solutions, of the compactified SUGRA theory interpolate between the past and future light cones of the moduli space. We describe tentative generalizations of this analysis to moduli spaces with less SUSY.
Cosmic Dust Aggregation with Stochastic Charging

The coagulation of cosmic dust grains is a fundamental process which takes place in astrophysical environments, such as presolar nebulae and circumstellar and protoplanetary disks. Cosmic dust grains can become charged through interaction with their plasma environment or other processes, and the resultant electrostatic force between dust grains can strongly affect their coagulation rate. Since ions and electrons are collected on the surface of the dust grain at random time intervals, the electrical charge of a dust grain experiences stochastic fluctuations. In this study, a set of stochastic differential equations is developed to model these fluctuations over the surface of an irregularly shaped aggregate. Then, employing the data produced, the influence of the charge fluctuations on the coagulation process and the physical characteristics of the aggregates formed is examined. It is shown that dust with small charges (due to the small size of the dust grains or a tenuous plasma environment) is affected most strongly.
The long history of the Rossiter-McLaughlin effect and its recent applications

In this paper I will review the Rossiter-McLaughlin (RM) effect; its history, how it manifests itself during stellar eclipses and planetary transits, and the increasingly important role its measurements play in guiding our understanding of the formation and evolution of close binary stars and exoplanet systems.
Low Mach number fluctuating hydrodynamics of binary liquid mixtures

Continuing on our previous work (A. Donev, A. Nonaka, Y. Sun, T. G. Fai, A. L. Garcia and J. B. Bell, Comm. App. Math. and Comp. Sci. 9 (2014), no. 1, 47–105), we develop semi-implicit numerical methods for solving low Mach number fluctuating hydrodynamic equations appropriate for modeling diffusive mixing in isothermal mixtures of fluids with different densities and transport coefficients. We treat viscous dissipation implicitly using a recently developed variable-coefficient Stokes solver (M. Cai, A. J. Nonaka, J. B. Bell, B. E. Griffith and A. Donev, Commun. Comput. Phys. 16 (2014), no. 5, 1263–1297). This allows us to increase the time step size significantly for low Reynolds number flows with large Schmidt numbers compared to our earlier explicit temporal integrator. Also, unlike most existing deterministic methods for low Mach number equations, our methods do not use a fractional time-step approach in the spirit of projection methods, thus avoiding splitting errors and giving full second-order deterministic accuracy even in the presence of boundaries for a broad range of Reynolds numbers including steady Stokes flow. We incorporate the Stokes solver into two time-advancement schemes, where the first is suitable for inertial flows and the second is suitable for the overdamped limit (viscous-dominated flows), in which inertia vanishes and the fluid motion can be described by a steady Stokes equation. We also describe how to incorporate advanced higher-order Godunov advection schemes in the numerical method, allowing for the treatment of (very) large Peclet number flows with a vanishing mass diffusion coefficient. We incorporate thermal fluctuations in the description in both the inertial and overdamped regimes. We validate our algorithm with a series of stochastic and deterministic tests. Finally, we apply our algorithms to model the development of giant concentration fluctuations during the diffusive mixing of water and glycerol, and compare numerical results with experimental measurements. We find good agreement between the two, and observe propagative (nondiffusive) modes at small wavenumbers (large spatial scales), not reported in published experimental measurements of concentration fluctuations in fluid mixtures. Our work forms the foundation for developing low Mach number fluctuating hydrodynamics methods for miscible multispecies mixtures of chemically reacting fluids.
Large Deviations Principle for a Large Class of One-Dimensional Markov Processes

We study the large deviations principle for one-dimensional, continuous, homogeneous, strong Markov processes that do not necessarily behave locally as a Wiener process. Any strong Markov process Xt in ℝ that is continuous with probability one, under some minimal regularity conditions, is governed by a generalized elliptic operator DvDu, where v and u are two strictly increasing functions, v is right-continuous and u is continuous. In this paper, we study large deviations principle for Markov processes whose infinitesimal generator is eDvDu where 0<e≪1. This result generalizes the classical large deviations results for a large class of one-dimensional “classical” stochastic processes. Moreover, we consider reaction-diffusion equations governed by a generalized operator DvDu. We apply our results to the problem of wavefront propagation for these type of reaction-diffusion equations.
The Resolved Distributions of Dust Mass and Temperature in Local Group Galaxies

We utilize archival far-infrared maps from the Herschel Space Observatory in four Local Group galaxies (Small and Large Magellanic Clouds, M31, and M33). We model their Spectral Energy Distribution (SED) from 100 to 500 $\mu$m using a single-temperature modified blackbody emission with a fixed emissivity index of $\beta = 1.8$. From the best-fit model, we derive the dust temperature, $T_{\rm d}$, and the dust mass surface density, $\Sigma_{\rm d}$, at 13 parsec resolution for SMC and LMC, and at 167 parsec resolution for all targets. This measurement allows us to build the distribution of dust mass and luminosity as functions of dust temperature and mass surface density. We compare those distribution functions among galaxies and between regions in a galaxy. We find that LMC has the highest mass-weighted average $T_{\rm d}$, while M31 and M33 have the lowest mass-weighted average $T_{\rm d}$. Within a galaxy, star forming regions have higher $T_{\rm d}$ and $\Sigma_{\rm d}$ relative to the overall distribution function, due to more intense heating by young stars and higher gas mass surface density. When we degrade the resolutions to mimic distant galaxies, the mass-weighted mean temperature gets warmer as the resolution gets coarser, meaning the temperature derived from unresolved observation is systematically higher than that in highly resolved observation. As an implication, the total dust mass is lower (underestimated) in coarser resolutions. This resolution-dependent effect is more prominent in clumpy star-forming galaxies (SMC, LMC, and M33), and less prominent in more quiescent massive spiral (M31).
Finite-dimensional quotients of Hecke algebras

Let W be a complex reflection group. We prove that there is the maximal finite dimensional quotient of the Hecke algebra H_q(W) of W and that the dimension of this quotient coincides with |W|. This is a weak version of a Brou\'e-Malle-Rouquier conjecture from 1998. The proof is based on categories O for Rational Cherednik algebras.
Resonance free regions for nontrapping manifolds with cusps

We prove resolvent estimates for nontrapping manifolds with cusps which imply the existence of arbitrarily wide resonance free strips, local smoothing for the Schrodinger equation, and resonant wave expansions. We obtain lossless limiting absorption and local smoothing estimates, but the estimates on the holomorphically continued resolvent exhibit losses. We prove that these estimates are optimal in certain respects.
The CAT vehicle testbed: A simulator with hardware in the loop for autonomous vehicle applications

National Science Foundation; Air Force Office of Scientific Research [1253334, 1262960, 1419419, 1446435, 1446690, 1446702, 1446715 1521617]
Constraints on OH Megamaser Excitation from a Survey of OH Satellite Lines

We report the results of a full-Stokes survey of all four 18 cm OH lines in 77 OH megamasers (OHMs) using the Arecibo Observatory. This is the first survey of OHMs that included observations of the OH satellite lines; only four of the 77 OHMs have existing satellite line observations in the literature. Satellite line emission is detected in five sources, three of which are redetections of previously published sources. The two sources with new detections of satellite line emission are IRAS F10173+0829, which was detected at 1720 MHz, and IRAS F15107+0724, for which both the 1612 MHz and 1720 MHz lines were detected. In IRAS F15107+0724, the satellite lines are partially conjugate, as 1720 MHz absorption and 1612 MHz emission have the same structure at some velocities within the source, along with additional broader 1612 MHz emission. This is the first observed example of conjugate satellite lines in an OHM. In the remaining sources, no satellite line emission is observed. The detections and upper limits are generally consistent with models of OHM emission in which all of the 18 cm OH lines have the same excitation temperature. There is no evidence for a significant population of strong satellite linemore » emitters among OHMs.« less
SELF-CONSISTENT SIZE AND VELOCITY DISTRIBUTIONS OF COLLISIONAL CASCADES

The standard theoretical treatment of collisional cascades derives a steady-state size distribution assuming a single constant velocity dispersion for all bodies regardless of size. Here we relax this assumption and solve self-consistently for the bodies' steady-state size and size-dependent velocity distributions. Specifically, we account for viscous stirring, dynamical friction, and collisional damping of the bodies' random velocities in addition to the mass conservation requirement typically applied to find the size distribution in a steady-state cascade. The resulting size distributions are significantly steeper than those derived without velocity evolution. For example, accounting self-consistently for the velocities can change the standard q = 3.5 power-law index of the Dohnanyi differential size spectrum to an index as large as q = 4. Similarly, for bodies held together by their own gravity, the corresponding power-law index range 2.88 < q < 3.14 of Pan & Sari can steepen to values as large as q = 3.26. Our velocity results allow quantitative predictions of the bodies' scale heights as a function of size. Together with our predictions, observations of the scale heights for different-sized bodies for the Kuiper belt, the asteroid belt, and extrasolar debris disks may constrain the mass and number of large bodies stirring the cascade as well as the colliding bodies' internal strengths.
Response theory of the ergodic many-body delocalized phase: Keldysh Finkel’stein sigma models and the 10-fold way

Abstract We derive the finite temperature Keldysh response theory for interacting fermions in the presence of quenched short-ranged disorder, as applicable to any of the 10 Altland–Zirnbauer classes in an Anderson delocalized phase with at least a U(1) continuous symmetry. In this formulation of the interacting Finkel’stein nonlinear sigma model, the statistics of one-body wave functions are encoded by the constrained matrix field, while physical correlations follow from the hydrodynamic density or spin response field, which decouples the interactions. Integrating out the matrix field first, we obtain weak (anti) localization and Altshuler–Aronov quantum conductance corrections from the hydrodynamic response function. This procedure automatically incorporates the correct infrared cutoff physics, and in particular gives the Altshuler–Aronov–Khmelnitsky (AAK) equations for dephasing of weak (anti)localization due to electron–electron collisions. We explicate the method by deriving known quantumcorrections in two dimensions for the symplectic metal class AII, as well as the spin-SU(2) invariant superconductor classes C and CI. We show that quantum conductance corrections due to the special modes at zero energy in nonstandard classes are automatically cut off by temperature, as previously expected, while the Wigner–Dyson class Cooperon modes that persist to all energies are cut by dephasing. We also show that for short-ranged interactions, the standard self-consistent solution for the dephasing rate is equivalent to a particular summation of diagrams via the self-consistent Born approximation. This should be compared to the corresponding AAK solution for long-ranged Coulomb interactions, which exploits the Markovian noise correlations induced by thermal fluctuations of the electromagnetic field. We discuss prospects for exploring the many-body localization transition as a dephasing catastrophe in short-range interacting models, as encountered by approaching from the ergodic side.
Application of the Biot–Savart law to parabolic vortex segments using elliptic integrals

The Biot–Savart law is used in aerodynamic theory to calculate the velocity induced by curved vortex lines. Explicit formulas are developed, using multivariate Appell hypergeometric functions, for the velocity induced by a general parabolic vortex segment. The formulas are derived by constructing a particular pencil of elliptic curves whose period integrals provide the solution to the induced velocity. We use numerical integration and a perturbation expansion to evaluate the validity of our formulas.
ASYMPTOTIC SYMMETRY GROUPS OF LONG-RANGED GAUGE CONFIGURATIONS

We make some general remarks on long-ranged configurations in gauge or diffeomorphism invariant theories where the fields are allowed to assume some nonvanishing values at spatial infinity. In this case the Gauss constraint only eliminates those gauge degrees of freedom which lie in the connected component of asymptotically trivial gauge transformations. This implies that proper physical symmetries arise either from gauge transformations that reach to infinity or those that are asymptotically trivial but do not lie in the connected component of transformations within that class. The latter transformations form a discrete subgroup of all symmetries whose position in the ambient group has proven to have interesting implications. We explain this for the dyon configuration in the SO(3) Yang-Mills-Higgs theory, where we prove that the asymptotic symmetry group is Z|m|×ℝ where m is the monopole number. We also discuss the application of the general setting to general relativity and show that here the only implication of discrete symmetries for the continuous part is a possible extension of the rotation group SO(3) to SU(2).
A Procedure for Correcting the Apparent Optical Depths of Moderately Saturated Interstellar Absorption Lines

Presently, most observations of absorption lines from interstellar and intergalactic matter have sufficient resolution to show most of the structure at differing radial velocities of the absorber. This added information allows one to go beyond the practice of just obtaining equivalent widths. As with measurements of Wλ, however, it is important to sense and correct for the fact that some parts of a profile may arise from absorption peaks that are strong enough to be saturated. This elect may be unrecognized, or at least underappreciated, in those cases where the narrowest velocity structures are degraded by the convolution of the true spectrum by the instrumental profile. Using a procedure that is virtually identical to the curve-of-growth method for equivalent widths, one can compare at any velocity the apparent optical depths τa of two lines that have significantly different transition probabilities. If their ratio is smaller than the ratio of the lines values of fλ, the actual saturation is more severe than that indicated by the values of τa. This paper describes a simple procedure for selectively boosting the τa of the weaker of the two lines so that the unresolved saturated structure is accounted for. This enables one to obtain a very nearly correct answer for the column density per unit velocity. (However, the lost velocity detail is not restored.) Two synthetic test examples of very complex, saturated profiles are analyzed with this method in order to show how well it works. A demonstration with real observations is also presented. An explicit, easily computed formula that is a very close approximation to the real correction factors is given, to make data analysis and error estimation more convenient.
Regenesis and quantum traversable wormholes

Recent gravity discussions of a traversable wormhole indicate that in holographic systems signals generated by a source could reappear long after they have dissipated, with the need of only performing some simple operations. In this paper we argue the phenomenon, to which we refer as “regenesis”, is universal in general quantum chaotic many-body systems, and elucidate its underlying physics. The essential elements behind the phenomenon are: (i) scrambling which in a chaotic system makes out-of-time-ordered correlation functions (OTOCs) vanish at large times; (ii) the entanglement structure of the state of the system. The latter aspect also implies that the regenesis phenomenon requires fine tuning of the initial state. Compared to other manifestations of quantum chaos such as the initial growth of OTOCs which deals with early times, and a random matrix-type energy spectrum which reflects very large time behavior, regenesis concerns with intermediate times, of order the scrambling time of a system. We also study the phenomenon in detail in general two-dimensional conformal field theories in the large central charge limit, and highlight some interesting features including a resonant enhancement of regenesis signals near the scrambling time and their oscillations in coupling. Finally, we discuss gravity implications of the phenomenon for systems with a gravity dual, arguing that there exist regimes for which traversability of a wormhole is quantum in nature, i.e. cannot be associated with a semi-classical spacetime causal structure.
PRIMUS+DEEP2: The Dependence of Galaxy Clustering on Stellar Mass and Specific Star Formation Rate at 0.2 < z < 1.2

We present results on the clustering properties of galaxies as a function of both stellar mass and specific star formation rate (sSFR) using data from the PRIMUS and DEEP2 galaxy redshift surveys spanning 0.2 < z < 1.2. We use spectroscopic redshifts of over 100,000 galaxies covering an area of 7.2 deg^2 over five separate fields on the sky, from which we calculate cosmic variance errors. We find that the galaxy clustering amplitude is as strong of a function of sSFR as of stellar mass, and that at a given sSFR, it does not significantly depend on stellar mass within the range probed here. We further find that within the star-forming population and at a given stellar mass, galaxies above the main sequence of star formation with higher sSFR are less clustered than galaxies below the main sequence with lower sSFR. We also find that within the quiescent population, galaxies with higher sSFR are less clustered than galaxies with lower sSFR, at a given stellar mass. We show that the galaxy clustering amplitude smoothly increases with both increasing stellar mass and decreasing sSFR, implying that galaxies likely evolve across the main sequence, not only along it, before galaxies eventually become quiescent. These results imply that the stellar mass to halo mass relation, which connects galaxies to dark matter halos, likely depends on sSFR.
The universality of the Rezk nerve

We functorially associate to each relative $\infty$-category $(R,W)$ a simplicial space $N^R_\infty(R,W)$, called its Rezk nerve (a straightforward generalization of Rezk's "classification diagram" construction for relative categories). We prove the following local and global universal properties of this construction: (i) that the complete Segal space generated by the Rezk nerve $N^R_\infty(R,W)$ is precisely the one corresponding to the localization $R[[W^{-1}]]$; and (ii) that the Rezk nerve functor defines an equivalence $RelCat_\infty [[ W_{BK}^{-1} ]] \xrightarrow{\sim} Cat_\infty$ from a localization of the $\infty$-category of relative $\infty$-categories to the $\infty$-category of $\infty$-categories.
Rotating Wave Solutions to Lattice Dynamical Systems II: Persistence Results

This work comes as the second part in a series of investigations into the dynamics of rotating waves as solutions to lattice dynamical systems. Such nonlinear waves as solutions to mathematical equations are of great interest throughout the physical sciences due to their association with many electrophysiological pathologies and this investigation aims to further the understanding of rotating waves from a mathematical perspective. Here we focus on so-called Lambda–Omega differential equations, a well-studied generalization of the celebrated Ginzburg–Landau equation, to show that there exists an interval of sufficiently small coupling values for which a rotating wave solution persists. This result is achieved using a wide range of functional analytic tools, primarily in an effort to apply a non-standard implicit function theorem. This work initiates subsequent studies into the dynamics and bifurcations of rotating waves away from the reaction–diffusion equation setting to differential equations for which traditional symmetry based centre manifold reductions cannot be applied.
The four fixed points of scale invariant single field cosmological models

We introduce a new set of flow parameters to describe the time dependence of the equation of state and the speed of sound in single field cosmological models. A scale invariant power spectrum is produced if these flow parameters satisfy specific dynamical equations. We analyze the flow of these parameters and find four types of fixed points that encompass all known single field models. Moreover, near each fixed point we uncover new models where the scale invariance of the power spectrum relies on having simultaneously time varying speed of sound and equation of state. We describe several distinctive new models and discuss constraints from strong coupling and superluminality.
Scalar Quantization With Random Thresholds

The distortion-rate performance of certain randomly-designed scalar quantizers is determined. The central results are the mean-squared error distortion and output entropy for quantizing a uniform random variable with thresholds drawn independently from a uniform distribution. The distortion is at most six times that of an optimal (deterministically-designed) quantizer, and for a large number of levels the output entropy is reduced by approximately (1-γ)/(ln 2) bits, where γ is the Euler-Mascheroni constant. This shows that the high-rate asymptotic distortion of these quantizers in an entropy-constrained context is worse than the optimal quantizer by at most a factor of 6e-2(1-γ) ≈ 2.58.
The Formation of Dwarf Galaxies in Tidal Debris: A Study of the Compact Group Environment

From R-band images of 42 Hickson compact groups, we present a sample of 47 candidate dwarf galaxies that are associated with the tidal tails and arms in the groups. The candidates, found in 15 tidal features, have R magnitudes and masses (for M/L = 1) in the ranges -16.5 < M_R - 5 log h_{75} < -11.5 and 2x10^6 M_{\odot} < M < 2x10^8 M_{\odot}, respectively. Their masses and locations are compared to the predictions of theoretical/N-body tidal dwarf formation scenarios. Considering the longevity of tidal debris in the compact group environment and the results of this survey, we estimate the contribution of the tidal dwarf formation mechanism to the population of dwarf galaxies observed at large in compact groups. If the majority of our dwarf galaxy candidates are confirmed as being gravitationally bound stellar systems, then a significant fraction, perhaps as much as one-half, of the dwarf population in compact groups is the product of interactions among giant parent galaxies.
Probabilistic Semantic Retrieval for Surveillance Videos With Activity Graphs

We present a novel framework for finding complex activities matching user-described queries in cluttered surveillance videos. The wide diversity of queries coupled with the unavailability of annotated activity data limits our ability to train activity models. To bridge the semantic gap, we propose letting users describe an activity as a semantic graph with object attributes and inter-object relationships associated with nodes and edges, respectively. We learn node/edge-level visual predictors during training and, at test-time, propose retrieving activity by identifying likely locations that match the semantic graph. We formulate a novel conditional random field-based probabilistic activity localization objective that accounts for misdetections, misclassifications and track losses, and outputs a likelihood score for a candidate grounded location of the query in the video. We seek groundings that maximize overall precision and recall. To handle the combinatorial search over all high-probability groundings, we propose a highest precision subgraph matching algorithm. Our method outperforms existing retrieval methods on benchmarked datasets.