cssi/SciSciGPT-SciSciNet huggingface dataset:
New search for mirror neutron regeneration

The possibility of relatively fast neutron oscillations into a mirror neutron state is not excluded experimentally when a mirror magnetic field is considered. Direct searches for the disappearance of neutrons into mirror neutrons in a controlled magnetic field have previously been performed using ultracold neutrons, with some anomalous results reported. We describe a technique using cold neutrons to perform a disappearance and regeneration search, which would allow us to unambiguously identify a possible oscillation signal. An experiment using the existing General Purpose-Small Angle Neutron Scattering instrument at the High Flux Isotope Reactor at Oak Ridge National Laboratory will have the sensitivity to fully explore the parameter space of prior ultracold neutron searches and confirm or refute previous claims of observation. This instrument can also conclusively test the validity of recently suggested oscillation-based explanations for the neutron lifetime anomaly.
Third generation superpartners: Results from ATLAS and CMS

These proceedings discuss results from recent searches for third generation SUSY particles by the ATLAS and CMS experiments at the LHC. Analyses performed with 8 TeV data probing direct pair production of bottom and top squarks are presented.
EVALUATION OF DECOHERENCE FOR QUANTUM COMPUTING ARCHITECTURES: QUBIT SYSTEM SUBJECT TO TIME-DEPENDENT CONTROL

We present an approach that allows quantifying decoherence processes in an open quantum system subject to external time-dependent control. Interactions with the environment are modeled by a standard bosonic heat bath. We develop two unitarity-preserving approximation schemes to calculate the reduced density matrix. One of the approximations relies on a short-time factorization of the evolution operator, while the other utilizes expansion in terms of the system-bath coupling strength. Applications are reported for two illustrative systems: an exactly solvable adiabatic model, and a model of a rotating-wave quantum-computing gate function. The approximations are found to produce consistent results at short and intermediate times.
On the existence of roton excitations in Bose-Einstein condensates: Signature of proximity to a Mott insulating phase

Within the last decade, artificially engineered Bose–Einstein condensation has been achieved in atomic systems, Bose–Einstein Condensates (BECs) are superfluids just like bosonic helium is and all interacting bosonic fluids are expected to be at low enough temperatures. One difference between the two systems is that superfluid helium exhibits roton excitations while Bose–Einstein condensates have never been observed to have such excitations. The reason for the roton minimum in helium is its proximity to a solid phase. The roton minimum is a consequence of enhanced density fluctuations at the reciprocal lattice vector of the stillborn solid. Bose–Einstein condensates in atomic traps are not near a solid phase and therefore do not exhibit roton minimum. We conclude that if Bose–Einstein condensates in an optical lattice are tuned near a transition to a Mott insulating phase, a roton minimum will develop at a reciprocal lattice vector of the lattice. Equivalently, a peak in the structure factor will appear at such a wavevector. The smallness of the roton gap or the largeness of the structure factor peak are experimental signatures of the proximity to the Mott transition.
Gene Drive Dynamics in Natural Populations: The Importance of Density Dependence, Space, and Sex

The spread of synthetic gene drives is often discussed in the context of panmictic populations connected by gene flow and described with simple deterministic models. Under such assumptions, an entire species could be altered by releasing a single individual carrying an invasive gene drive, such as a standard homing drive. While this remains a theoretical possibility, gene drive spread in natural populations is more complex and merits a more realistic assessment. The fate of any gene drive released in a population would be inextricably linked to the population's ecology. Given the uncertainty often involved in ecological assessment of natural populations, understanding the sensitivity of gene drive spread to important ecological factors is critical. Here we review how different forms of density dependence, spatial heterogeneity, and mating behaviors can impact the spread of self-sustaining gene drives. We highlight specific aspects of gene drive dynamics and the target populations that need further research.
Patterns in Illinois Educational School Data.

Applying physics-based data visualization techniques to analyze performance of students at public schools in Illinois.
Oscillatory Breuer–Major theorem with application to the random corrector problem

In this paper, we present an oscillatory version of the celebrated Breuer-Major theorem that is motivated by the random corrector problem. As an application, we are able to prove new results concerning the Gaussian fluctuation of the random corrector. We also provide a variant of this theorem involving homogeneous measures.
General Relativistic Modeling of Magnetized Jets from Accreting Black Holes

Recent advances in general relativistic magnetohydrodynamic modeling of jets offer unprecedented insights into the inner workings of accreting black holes that power the jets in active galactic nuclei (AGN) and other accretion systems. I will present the results of recent studies that determine spin-dependence of jet power and discuss the implications for the AGN radio loud/quiet dichotomy and recent observations of high jet power in a number of AGN.
ULTRAVIOLET ISM DIAGNOSTICS FOR STAR-FORMING GALAXIES. I. TRACERS OF METALLICITY AND EXTINCTION

We have observed a sample of 14 nearby () star-forming blue compact galaxies (BCGs) in the rest-frame far-UV (~1150–2200 A) using the Cosmic Origins Spectrograph on the Hubble Space Telescope. We have also generated a grid of stellar population synthesis models using the Starburst99 evolutionary synthesis code, allowing us to compare observations and theoretical predictions for the Si iv_1400 and C iv_1550 UV indices; both are comprised of a blend of stellar wind and interstellar lines and have been proposed as metallicity diagnostics in the UV. Our models and observations both demonstrate that there is a positive linear correlation with metallicity for both indices, and we find generally good agreement between our observations and the predictions of the Starburst99 models (with the models slightly under-estimating the value of the indices due to contributions from interstellar lines not simulated by a stellar population synthesis code). By combining the rest-frame UV observations with pre-existing rest-frame optical spectrophotometry of our BCG sample, we also directly compare the predictions of metallicity and extinction diagnostics across both wavelength regimes. This comparison reveals a correlation between the UV absorption and optical strong-line diagnostics, offering the first means of directly comparing interstellar medium (ISM) properties determined across different rest-frame regimes. Finally, using our Starburst99 model grid, we determine theoretical values for the short-wavelength UV continuum slope, , which can be used for determining extinction in rest-frame UV spectra of star-forming galaxies. We consider the implications of these results and discuss future work aimed at parameterizing these and other environmental diagnostics in the UV (a suite of diagnostics that could offer particular utility in the study of star-forming galaxies at high redshift) as well as the development of robust comparisons between ISM diagnostics across a broad wavelength baseline.
An algorithm to determine the Heegaard genus of a 3–manifold

We give an algorithmic proof of the theorem that a closed orientable irreducible and atoroidal 3–manifold has only finitely many Heegaard splittings in each genus, up to isotopy. The proof gives an algorithm to determine the Heegaard genus of an atoroidal 3–manifold.
The Color Distributions of Globular Clusters in Virgo Elliptical Galaxies

This Letter presents the color distributions of the globular cluster (GC) systems of 12 Virgo elliptical galaxies, measured using data from the Hubble Space Telescope. Bright galaxies with large numbers of detected GCs show two distinct cluster populations with mean V-I colors near 1.01 and 1.26. The GC population of M86 is a clear exception; its color distribution shows a single, sharp peak near V-I=1.03. The absence of the red population in this galaxy, and the consistency of the peak colors in the others, may be indications of the origins of the two populations found in most bright elliptical galaxies.
Testing gravity with gravitational wave source counts

We show that the gravitational wave source counts distribution can test how gravitational radiation propagates on cosmological scales. This test does not require obtaining redshifts for the sources. If the signal-to-noise ratio (ρ) from a gravitational wave source is proportional to the strain then it falls as , thus we expect the source counts to follow . However, if gravitational waves decay as they propagate or propagate into other dimensions, then there can be deviations from this generic prediction. We consider the possibility that the strain falls as , where recovers the expected predictions in a Euclidean uniformly-filled Universe, and forecast the sensitivity of future observations to deviations from standard General Relativity. We first consider the case of few objects, seven sources, with a signal-to-noise from 8 to 24, and impose a lower limit on γ, finding at 95% confidence level. The distribution of our simulated sample is very consistent with the distribution of the trigger events reported by Advanced LIGO. Future measurements will improve these constraints: with 100 events, we estimate that γ can be measured with an uncertainty of 15%. We generalize the formalism to account for a range of chirp masses and the possibility that the signal falls as .
Conformal sequestering simplified

Sequestering is important for obtaining flavor-universal soft masses in models where supersymmetry breaking is mediated at high scales. We construct a simple and robust class of hidden sector models which sequester themselves from the visible sector due to strong and conformally invariant hidden dynamics. Masses for hidden matter eventually break the conformal symmetry and lead to supersymmetry breaking by the mechanism recently discovered by Intriligator, Seiberg and Shih. We give a unified treatment of subtleties due to global symmetries of the CFT. There is enough review for the paper to constitute a self-contained account of conformal sequestering.
Multi-scale dynamics of magnetic flux tubes and inverse magnetic energy transfer

We report on an analytical and numerical study of the dynamics of a three-dimensional array of identical magnetic flux tubes in the reduced-magnetohydrodynamic description of the plasma. We propose that the long-time evolution of this system is dictated by flux-tube mergers, and that such mergers are dynamically constrained by the conservation of the pertinent (ideal) invariants, viz. the magnetic potential and axial fluxes of each tube. We also propose that in the direction perpendicular to the merging plane, flux tubes evolve in a critically balanced fashion. These notions allow us to construct an analytical model for how quantities such as the magnetic energy and the energy-containing scale evolve as functions of time. Of particular importance is the conclusion that, like its two-dimensional counterpart, this system exhibits an inverse transfer of magnetic energy that terminates only at the system scale. We perform direct numerical simulations that confirm these predictions and reveal other interesting aspects of the evolution of the system. We find, for example, that the early time evolution is characterized by a sharp decay of the initial magnetic energy, which we attribute to the ubiquitous formation of current sheets. We also show that a quantitatively similar inverse transfer of magnetic energy is observed when the initial condition is a random, small-scale magnetic seed field.
Hypergraph Ramsey numbers: tight cycles versus cliques

For s 4, the 3-uniform tight cycle C 3 s has vertex set corresponding to s distinct points on a circle and edge set given by the s cyclic intervals of three consecutive points. For xed s 4 and s6 0 (mod 3) we prove that there are positive constants a and b with 2 at 5 is proved by using supersaturation and the known upper bound for r(K 3 4;K 3 t ), while for s = 5 it follows from a new upper bound for r(K 3
Collective symmetry breaking and resonant non-gaussianity

We study inflationary models that produce a nearly scale-invariant power spectrum while breaking scale invariance significantly in the bispectrum. Under most circumstances, such models are finely-tuned, as radiative corrections generically induce a larger signal in the power spectrum. However, when scale invariance is broken collectively (i.e., it requires more than one coupling to break the symmetry), these radiative corrections may be suppressed. We illustrate the features and limitations of collective symmetry breaking in the context of resonant non-gaussianity. We discuss two examples where oscillatory features can arise predominantly in the bispectrum.
Ghosts- and tachyon-free regions of the Randall-Sundrum model parameter space

Model building within the Randall-Sundrum (RS) framework generally involves placing the Standard Model fields in the bulk. Such fields may possess non-zero values for their associated brane-localized kinetic terms (BLKTs) in addition to possible bulk mass parameters. In this paper we clearly identify the regions of the RS model parameter space where the presence of bulk mass terms and BLKTs yield a setup which is free from both ghost and tachyon instabilities. Such physically acceptable parameter space regions can then be used to construct realistic and phenomenologically viable RS models.
Modeling Hall viscosity in magnetic-skyrmion systems

Recent Skyrmion Hall Transport measurements have revealed asymmetry between Skyrmion and Anti-Skyrmion Hall angles. The author shows this unusual asymmetry can be explained by generalizing the Thiele equation with a transverse velocity component, which is directly related to the Hall viscosity. Surprisingly, experimental data indicate the Hall viscosity accounts for 3% - 5.4% of the Skyrmion Hall effect.
Reversal Time of Jump-Noise Dynamics for Large Nucleation

The jump-noise is a phenomenological stochastic process used to model the thermal fluctuation of magnetization in nanomagnets. In this paper, the large nucleation regime of jump-noise dynamics is studied, and its reversal time is characterized from Monte Carlo simulations and analysis. Results show that the reversal time of jump-noise dynamics for large nucleation is asymptotically equal to the time constant associated with a single jump-noise scattering event from the energy minimum in the energy landscape of the magnetization. The reversal time for large nucleation depends linearly on the height of the energy barrier for large barriers. The significance of the large nucleation regime of jump-noise dynamics to phenomenologically explain the magnetoelectric switching of antiferromagnetic order parameter is also prospected.
Dynamics of radiatively inefficient flows accreting onto radiatively efficient black hole objects

I present results from numerical simulations of gas dynamics outside luminous accretion disks in active galactic nuclei. The gas, gravitationally captured by a super massive black hole, can be driven away by the energy and momentum of the radiation emitted during black hole accretion. Assuming axisymmetry, I study how the mass accretion and outflow rates, and the flow dynamics respond to changes in radiation heating relative to radiation pressure. I find that for a 10^8 MSUN black hole with the accretion luminosity of 0.6 of the Eddington luminosity the flow settles into a steady state and has two components: (1) an equatorial inflow and (2) a bipolar inflow/outflow with the outflow leaving the system along the disk rotational axis. The inflow is a realization of a Bondi-like accretion flow. The second component is an example of a non-radial accretion flow which becomes an outflow once it is pushed close to the rotational axis where thermal expansion and radiation pressure accelerate it outward. The main result of this preliminary work is that although the above two-component solution is robust, its properties are sensitive to the geometry and spectral energy distribution of the radiation field.
Statistical mechanics of complex neural systems and high dimensional data

Recent experimental advances in neuroscience have opened new vistas into the immense complexity of neuronal networks. This proliferation of data challenges us on two parallel fronts. First, how can we form adequate theoretical frameworks for understanding how dynamical network processes cooperate across widely disparate spatiotemporal scales to solve important computational problems? Second, how can we extract meaningful models of neuronal systems from high dimensional datasets? To aid in these challenges, we give a pedagogical review of a collection of ideas and theoretical methods arising at the intersection of statistical physics, computer science and neurobiology. We introduce the interrelated replica and cavity methods, which originated in statistical physics as powerful ways to quantitatively analyze large highly heterogeneous systems of many interacting degrees of freedom. We also introduce the closely related notion of message passing in graphical models, which originated in computer science as a distributed algorithm capable of solving large inference and optimization problems involving many coupled variables. We then show how both the statistical physics and computer science perspectives can be applied in a wide diversity of contexts to problems arising in theoretical neuroscience and data analysis. Along the way we discuss spin glasses, learning theory, illusions of structure in noise, random matrices, dimensionality reduction and compressed sensing, all within the unified formalism of the replica method. Moreover, we review recent conceptual connections between message passing in graphical models, and neural computation and learning. Overall, these ideas illustrate how statistical physics and computer science might provide a lens through which we can uncover emergent computational functions buried deep within the dynamical complexities of neuronal networks.
Magnetic fields in an expanding universe

We find a solution to 4D Einstein?Maxwell theory coupled to a massless dilaton field, for all values of the dilaton coupling, describing a Melvin magnetic field in an expanding universe with ?stiff matter? equation of state parameter w = +1. As the universe expands, magnetic flux becomes more concentrated around the symmetry axis for dilaton coupling and more dispersed for . An electric field circulates around the symmetry axis in the direction determined by Lenz's law. For a = 0 the magnetic flux through a disc of fixed comoving radius is proportional to the proper area of the disc. This result disagrees with the usual expectation based on a test magnetic field that this flux should be constant, and we show why this difference arises. We also find a Melvin solution in an accelerating universe with w = ?7/9 for a dilaton field with a certain exponential potential.
Model atmospheres for low field neutron stars

We compute model atmospheres and emergent spectra for low field (B ∼< 10 G) neutron stars, using new opacity and equation of state data from the OPAL project. These computations, incorporating improved treatments of flux transport and convective stability, provide spectra for hydrogen, solar abundance and iron atmospheres. We compare our results to high field magnetic atmospheres, available only for hydrogen. An application to apparently thermal flux from the low field millisecond pulsar PSR J0437–4715 shows that H atmospheres fit substantially better than Fe models. We comment on extension to high fields and the implication of these results for neutron star luminosities and radii.
Matrix string theory and the Myers effect

A new configuration of non-abelian D1-branes growing into D5-branes is found. This time the effect is triggered by a non-trivial electric field on the world-volume of the D1-branes and a constant RR 4-form potential. Based on the these configurations and other observations regarding non-abelian effective actions, a new action for matrix string theory in non-trivial backgrounds is conjectured. As an application we found that fundamental strings can grow into Dp-branes, in particular by placing the strings in the background of a group of near horizon D3-branes we found D5-branes. These types of configurations were found from the supergravity point of view in previous works.
Late Bloomer Galaxies: Growing Up in Cosmic Autumn

Late bloomers are massive ($M_* >10^{10}\,M_\odot$) galaxies at $z<1$ that formed the majority of their stars within $\sim$2 Gyr of the epoch of observation. Our improved methodology for deriving star formation histories (SFHs) of galaxies at redshifts $0.45 < z < 0.75$ from the Carnegie-Spitzer-IMACS Survey includes confidence intervals that robustly distinguish late bloomers from "old" galaxies. We use simulated SFHs to test for "false positives" and contamination from old galaxies to demonstrate that the late bloomer population is not an artifact of our template modeling technique. We show that late bloomers account for $\sim$20% of $z\sim0.6$ galaxies with masses of the modern Milky Way, with a moderate dependence on mass. We take advantage of a 1% overlap of our sample with HST (CANDELS) imaging to construct a "gold standard" catalog of 74 galaxies with high-confidence SFHs, SEDs, basic data, and HST images to facilitate comparison with future studies by others. This small subset suggests that galaxies with both old and young SFHs cover the full range of morphology and environment (excluding rich groups or clusters), albeit with a mild but suggestive correlation with local environment. We begin the investigation of whether late bloomers of sufficient mass and frequency are produced in current-generation $\Lambda$CDM-based semi-analytic models of galaxy formation. In terms of halo growth, we find a late-assembling halo fraction within a factor-of-two of our late bloomer fraction. However, sufficiently delaying star formation in such halos may be a challenge for the baryon component of such models.
Telescopes don't make catalogues!

Astronomical instruments make intensity measurements; any precise astronomical experiment ought to involve modeling those mea- surements. People make catalogues, but because a catalogue requires hard decisions about calibration and detection, no catalogue can con- tain all of the information in the raw pixels relevant to most scientific investigations. Here we advocate making catalogue-like data outputs that permit investigators to test hypotheses with almost the power of the original image pixels. The key is to provide users with approxi- mations to likelihood tests against the raw image pixels. We advocate three options, in order of increasing difficulty: The first is t define cat- alogue entries and associated uncertainties such that the catalogue con- tains the parameters of an approximate description of the image-level likelihood function. The second is to produce a K-catalogue sampling in "catalogue space" that samples a posterior probability distribution of catalogues given the data. The third is to expose a web service or equivalent that can re-compute on demand the full image-level likeli- hood for any user-supplied catalogue. In probabilistic inference, the goal is to transform information gathered by the data-taking device into information about the model or parameters of interest, with as little loss as possible. The most precise methods for inference involve "forward modeling" of the measurements: A model that can generate the data accurately is a good model, and is constrained by every data element that it (interestingly) generates. For this reason, everyone who wants to perform a precise experiment with a telescope wants to model the image pixels. Recently, this has been realised in a range of astrophysics domains, from weak lensing (Bernstein & Jarvis 2002)
SPECTRAL VARIABILITY FROM THE PATCHY ATMOSPHERES OF T AND Y DWARFS

Brown dwarfs of a variety of spectral types have been observed to be photometrically variable. Previous studies have focused on objects at the L/T transition, where the iron and silicate clouds in L dwarfs break up or dissipate. However, objects outside of this transitional effective temperature regime also exhibit variability. Here, we present models for mid-late T dwarfs and Y dwarfs. We present models that include patchy salt and sulfide clouds as well as water clouds for the Y dwarfs. We find that for objects over 375 K, patchy cloud opacity would generate the largest amplitude variability within near-infrared spectral windows. For objects under 375 K, water clouds also become important and generate larger amplitude variability in the mid-infrared. We also present models in which we perturb the temperature structure at different pressure levels of the atmosphere to simulate hot spots. These models show the most variability in the absorption features between spectral windows. The variability is strongest at wavelengths that probe pressure levels at which the heating is the strongest. The most illustrative types of observations for understanding the physical processes underlying brown dwarf variability are simultaneous, multi-wavelength observations that probe both inside and outside of molecular absorption features. © 2014. The American Astronomical Society. All rights reserved.
The ideal of the trifocal variety

Techniques from representation theory, symbolic com- putational algebra, and numerical algebraic geometry are used to nd the minimal generators of the ideal of the trifocal variety. An eective test for determining whether a given tensor is a trifocal tensor is also given.
Calibrating Data from the Hinode/X-Ray Telescope and Associated Uncertainties

The X-Ray Telescope (XRT) onboard the Hinode satellite, launched 23 September 2006 by the Japan Aerospace Exploration Agency (JAXA), is a joint mission of Japan, the United States, and the United Kingdom to study the solar corona. In particular, XRT was designed to study solar plasmas with temperatures between 1 and 10 MK with ≈ 1″ pixels (≈ 2″ resolution). Prior to analysis, the data product from this instrument must be properly calibrated and data values quantified to accurately assess the information contained within. We present here the standard methods of calibration for these data. The calibration was performed on an empirical basis that uses the least complicated correction that accurately describes the data while suppressing spurious features. By analyzing the uncertainties remaining in the data after calibration, we conclude that the procedure is successful, because the remaining uncertainty after calibration is dominated by photon noise. This calibration software is available in the SolarSoft software library.
Reasoning about Goals, Steps, and Temporal Ordering with WikiHow

We propose a suite of reasoning tasks on two types of relations between procedural events: goal-step relations (“learn poses” is a step in the larger goal of “doing yoga”) and step-step temporal relations (“buy a yoga mat” typically precedes “learn poses”). We introduce a dataset targeting these two relations based on wikiHow, a website of instructional how-to articles. Our human-validated test set serves as a reliable benchmark for common-sense inference, with a gap of about 10% to 20% between the performance of state-of-the-art transformer models and human performance. Our automatically-generated training set allows models to effectively transfer to out-of-domain tasks requiring knowledge of procedural events, with greatly improved performances on SWAG, Snips, and Story Cloze Test in zero- and few-shot settings.
Stability of infinite systems of coupled oscillators via random walks on weighted graphs

Weakly coupled oscillators are used throughout the physical sciences, particularly in mathematical neuroscience to describe the interaction of neurons in the brain. Systems of weakly coupled oscillators have a well-known decomposition to a canonical phase model which forms the basis of our investigation in this work. Particularly, our interest lies in examining the stability of synchronous (phase-locked) solutions to this phase system: solutions with phases having the same temporal frequency but differ through time-independent phase-lags. The main stability result of this work comes from adapting a series of investigations into random walks on infinite weighted graphs. We provide an interesting link between the seemingly unrelated areas of coupled oscillators and random walks to obtain algebraic decay rates of small perturbations off the phase-locked solutions under some minor technical assumptions. We also provide some interesting and motivating examples that demonstrate the stability of phase-locked solutions, particularly that of a rotating wave solution arising in a well studied paradigm in the theory of coupled oscillators.
Integrated Radio Continuum Spectra of Galaxies

We investigate the spectral shape of the total continuum radiation, between 74 MHz and 5 GHz (400-6 cm in wavelength), for a large sample of bright galaxies. We take advantage of the overlapping survey coverage of the VLA Low-Frequency Sky Survey, the Westerbork Northern Sky Survey, the NRAO VLA Sky Survey, and the Green Bank 6 cm Survey to achieve significantly better resolution, sensitivity, and sample size compared to prior efforts of this nature. For our sample of 250 bright galaxies we measure a mean spectral index, α, of –0.69 between 1.4 and 4.85 GHz, –0.55 between 325 MHz and 1.4 GHz, and –0.45 between 74 and 325 MHz, which amounts to a detection of curvature in the mean spectrum. The magnitude of this curvature is approximately Δα = –0.2 per logarithmic frequency decade when fit with a generalized function having constant curvature. No trend in low-frequency spectral flattening versus galaxy inclination is evident in our data, suggesting that free-free absorption is not a satisfying explanation for the observed curvature. The ratio of thermal to non-thermal emission is estimated through two independent methods: (1) using the IRAS far-IR fluxes and (2) with the value of the total spectral index. Methodmore » (1) results in a distribution of 1.4 GHz thermal fractions of 9% ± 3%, which is consistent with previous studies, while method (2) produces a mean 1.4 GHz thermal fraction of 51% with dispersion 26%. The highly implausible values produced by method (2) indicate that the sum of typical power-law thermal and non-thermal components is not a viable model for the total spectral index between 325 and 1.4 GHz. An investigation into relationships between spectral index, infrared-derived quantities, and additional source properties reveals that galaxies with high radio luminosity in our sample are found to have, on average, a flatter radio spectral index, and early types tend to have excess radio emission when compared to the radio-infrared ratio of later types. Early types also have radio emission that is more compact than later type galaxies, as compared to the optical size of the galaxy. Despite these differences, no relation between spectral index and galaxy type is detected.« less
Managing Autonomous Mobility on Demand Systems for Better Passenger Experience

Autonomous mobility on demand systems, though still in their infancy, have very promising prospects in providing urban population with sustainable and safe personal mobility in the near future. While much research has been conducted on both autonomous vehicles and mobility on demand systems, to the best of our knowledge, this is the first work that shows how to manage autonomous mobility on demand systems for better passenger experience. We introduce the Expand and Target algorithm which can be easily integrated with three different scheduling strategies for dispatching autonomous vehicles. We implement an agent-based simulation platform and empirically evaluate the proposed approaches with the New York City taxi data. Experimental results demonstrate that the algorithm significantly improve passengers’ experience by reducing the average passenger waiting time by up to \(29.82\%\) and increasing the trip success rate by up to \(7.65\%\).
A Bayesian approach for predicting the popularity of tweets

We predict the popularity of short messages called tweets created in the micro-blogging site known as Twitter. We measure the popularity of a tweet by the time-series path of its retweets, which is when people forward the tweet to others. We develop a probabilistic model for the evolution of the retweets using a Bayesian approach, and form predictions using only observations on the retweet times and the local network or “graph” structure of the retweeters. We obtain good step ahead forecasts and predictions of the final total number of retweets even when only a small fraction (i.e., less than one tenth) of the retweet path is observed. This translates to good predictions within a few minutes of a tweet being posted, and has potential implications for understanding the spread of broader ideas, memes or trends in social networks.
THE NATURE OF THE ATMOSPHERE OF THE TRANSITING SUPER-EARTH GJ 1214b

The newly discovered planet GJ 1214b is the first known transiting super-Earth requiring a significant atmosphere to explain its observed mass and radius. Models for the structure of this planet predict that it likely possesses an H-He envelope of at least 0.05% of the total mass of the planet. However, models without a significant H-He atmosphere are not entirely ruled out by the available data. Here, we explore a range of possible atmospheres for the planet, ranging from solar composition gas, to pure CO2 or water (steam). We present transmission and emission spectra for each of these cases. We find that, if GJ 1214b possesses a hydrogen-rich atmosphere as expected, then the primary transit depth for such an atmosphere would vary at a level of up to 0.3% as a function of wavelength, relative to the background light of its M-dwarf host star. Observations at this level of precision are potentially obtainable with current space-based instrumentation. Successful detection of the transmission signature of this planet at the ~0.1% level would therefore provide confirmation of the hydrogen-rich nature of the planetary atmosphere. It follows that transmission spectroscopy at this level of precision could provide a first glimpse into answering the question of whether planets in the super-Earth mass regime (1-10 M ⊕) more closely resemble large terrestrial planets or small gas giant planets.
Adaptive algorithm for electronic structure calculations using reduction of Gaussian mixtures

We present a new adaptive method for electronic structure calculations based on novel fast algorithms for reduction of multivariate mixtures. In our calculations, spatial orbitals are maintained as...
Non-commutative worlds

This paper presents a mathematical view of aspects of physics, showing how the forms of gauge theory, Hamiltonian mechanics and quantum mechanics arise from a non-commutative framework for calculus and differential geometry. This work is motivated by discrete calculus, as it is shown that classical discrete calculus embeds in a non-commutative context. It is shown how various processes are modeled by non-commutative discrete calculus, and how aspects of differential geometry, such as the Levi-Civita connection, arise naturally from commutator equations and the Jacobi identity. A new and generalized version of the Feynman–Dyson derivation of electromagnetic equations is given, with corresponding discrete models.
Free Probability for Pairs of Faces I

We consider a notion of bi-freeness for systems of non-commutative random variables with two faces, one of left variables and another of right variables. This includes bi-free convolution operations, bi-free cumulants, the bi-free central limit, and bi-freeness with amalgamation over an algebra B.
Stabilizing Heegaard splittings of high-distance knots

Suppose $K$ is a knot in $S^3$ with bridge number $n$ and bridge distance greater than $2n$. We show that there are at most ${2n\choose n}$ distinct minimal genus Heegaard splittings of $S^3\setminus\eta(K)$. These splittings can be divided into two families. Two splittings from the same family become equivalent after at most one stabilization. If $K$ has bridge distance at least $4n$, then two splittings from different families become equivalent only after $n-1$ stabilizations. Further, we construct representatives of the isotopy classes of the minimal tunnel systems for $K$ corresponding to these Heegaard surfaces.
Cohomology and support varieties for Lie superalgebras II

In [2] (Preprint, 2006, arXiv:math.RT/0609363) the authors initiated a study of the representation theory of classical Lie superalgebras via a cohomological approach. Detecting subalgebras were constructed and a theory of support varieties was developed. The dimension of a detecting subalgebra coincides with the defect of the Lie superalgebra, and the dimension of the support variety for a simple supermodule was conjectured to equal the atypicality of the supermodule. In this paper the authors compute the support varieties of Kac supermodules for Type-I Lie superalgebras and of the simple supermodules for (m|n). The latter result verifies our earlier conjecture for (m|n). In our investigation we also delineate several of the major differences between Type-I versus Type-II classical Lie superalgebras. Finally, the connection between atypicality, defect and superdimension is made more precise by using the theory of support varieties and representations of Clifford superalgebras.
Linear forms in logarithms and integral points on higher-dimensional varieties

We apply inequalities from the theory of linear forms in logarithms to deduce effective results on S-integral points on certain higher-dimensional varieties when the cardinality of S is sufficiently small. These results may be viewed as a higher-dimensional version of an effective result of Bilu on integral points on curves. In particular, we prove a completely explicit result for integral points on certain affine subsets of the projective plane. As an application, we generalize an effective result of Vojta on the three-variable unit equation by giving an effective solution of the polynomial unit equation f(u,v)=w, where u, v, and w are S-units, |S|≤3, and f is a polynomial satisfying certain conditions (which are generically satisfied). Finally, we compare our results to a higher-dimensional version of Runge’s method, which has some characteristics in common with the results here.
CORONAL MAGNETOGRAPHY OF A SIMULATED SOLAR ACTIVE REGION FROM MICROWAVE IMAGING SPECTROPOLARIMETRY

We have simulated the Expanded Owens Valley Solar Array (EOVSA) radio images generated at multiple frequencies from a model solar active region, embedded in a realistic solar disk model, and explored the resulting data cube for different spectral analysis schemes to evaluate the potential for realizing one of EOVSA's most important scientific goals—coronal magnetography. In this paper, we focus on modeling the gyroresonance and free–free emission from an on-disk solar active region model with realistic complexities in electron density, temperature and magnetic field distribution. We compare the magnetic field parameters extrapolated from the image data cube along each line of sight after folding through the EOVSA instrumental profile with the original (unfolded) parameters used in the model. We find that even the most easily automated, image-based analysis approach (Level-0) provides reasonable quantitative results, although they are affected by systematic effects due to finite sampling in the Fourier (UV) plane. Finally, we note the potential for errors due to misidentified harmonics of the gyrofrequency, and discuss the prospects for applying a more sophisticated spectrally based analysis scheme (Level-1) to resolve the issue in cases where improved UV coverage and spatial resolution are available.
Grounded Compositional Outputs for Adaptive Language Modeling

Language models have emerged as a central component across NLP, and a great deal of progress depends on the ability to cheaply adapt them (e.g., through finetuning) to new domains and tasks. A language model's \emph{vocabulary}---typically selected before training and permanently fixed later---affects its size and is part of what makes it resistant to such adaptation. Prior work has used compositional input embeddings based on surface forms to ameliorate this issue. In this work, we go one step beyond and propose a fully compositional output embedding layer for language models, which is further grounded in information from a structured lexicon (WordNet), namely semantically related words and free-text definitions. To our knowledge, the result is the first word-level language model with a size that does not depend on the training vocabulary. We evaluate the model on conventional language modeling as well as challenging cross-domain settings with an open vocabulary, finding that it matches or outperforms previous state-of-the-art output embedding methods and adaptation approaches. Our analysis attributes the improvements to sample efficiency: our model is more accurate for low-frequency words.
LINEARIZED FORM OF THE GENERIC AFFINE-VIRASORO ACTION

Halpern and Yamron have given a Lorentz, conformal, and Diff S2-invariant world-sheet action for the generic irrational conformal field theory, but the action is highly nonlinear. In this paper, we introduce auxiliary fields to find an equivalent linearized form of the action, which shows in a very clear way that the generic affine-Virasoro action is a Diff S2-gauged WZW model. In particular, the auxiliary fields transform under Diff S2 as local Lie g× Lie g connections, so that the linearized affine-Virasoro action bears an intriguing resemblance to the usual (Lie algebra) gauged WZW model.
A MODEL OF LOW-LYING STATES IN STRONGLY INTERACTING ELECTROWEAK SYMMETRY-BREAKING SECTOR

It is proposed that, in a strongly-interacting electroweak sector, besides the Goldstone bosons, the coexistence of a scalar state (H) and vector resonances such as A1 [IG(JP)= 1–(1+)], V [1+(1–)] and ωH [0–(1–)] is required by the proper Regge behavior of the forward scattering amplitudes. This is a consequence of the following well-motivated assumptions: (a) Adler-Weisberger-type sum rules and the superconvergence relations for scattering amplitudes hold in this strongly interacting sector; (b) the sum rules at t=0 are saturated by a minimal set of low-lying states with appropriate quantum numbers. It therefore suggests that a complete description should include all these resonances. These states may lead to distinctive experimental signatures at future colliders.
Scaling Relations for Galaxies Prior to Reionization

The first galaxies in the universe are the building blocks of all observed galaxies. We present scaling relations for galaxies forming at redshifts z ≥ 15 when reionization is just beginning. We utilize the "Rarepeak" cosmological radiation hydrodynamics simulation that captures the complete star formation history in over 3300 galaxies, starting with massive Population III stars that form in dark matter halos as small as ~106 M ☉. We make various correlations between the bulk halo quantities, such as virial, gas, and stellar masses and metallicities and their respective accretion rates, quantifying a variety of properties of the first galaxies up to halo masses of 109 M ☉. Galaxy formation is not solely relegated to atomic cooling halos with virial temperatures greater than 104 K, where we find a dichotomy in galaxy properties between halos above and below this critical mass scale. Halos below the atomic cooling limit have a stellar mass-halo mass relationship log M 3.5 + 1.3log (M vir/107 M ☉). We find a non-monotonic relationship between metallicity and halo mass for the smallest galaxies. Their initial star formation events enrich the interstellar medium and subsequent star formation to a median of 10–2 Z ☉ and 10–1.5 Z ☉, respectively, in halos of total mass 107 M ☉, which is then diluted by metal-poor inflows well beyond Population III pre-enrichment levels of 10–3.5 Z ☉. The scaling relations presented here can be employed in models of reionization, galaxy formation, and chemical evolution in order to consider these galaxies forming prior to reionization.
Galactic binary science with the new LISA design

Building on the great success of the LISA Pathfinder mission, the outlines of a new LISA mission design were laid out at the 11th International LISA Symposium in Zurich. The revised design calls for three identical spacecraft forming an equilateral triangle with 2.5 million kilometer sides, and two laser links per side delivering full polarization sensitivity. With the demonstrated Pathfinder performance for the disturbance reduction system, and a well studied design for the laser metrology, it is anticipated that the new mission will have a sensitivity very close to the original LISA design. This implies that the mid-band performance, between 0.5 mHz and 3 mHz, will be limited by unresolved signals from compact binaries in our galaxy. Here we use the new LISA design to compute updated estimates for the galactic confusion noise, the number of resolvable galactic binaries, and the accuracy to which key parameters of these systems can be measured.
The quantum bialgebra associated with the eight-vertex R-matrix

The quantum bialgebra related to the Baxter's eight-vertexR-matrix is found as a quantum deformation of the Lie algebra of sl(2)-valued automorphic functions on a complex torus.
Haro 11: Where is the Lyman continuum source?

Identifying the mechanism by which high energy Lyman continuum (LyC) photons escaped from early galaxies is one of the most pressing questions in cosmic evolution. Haro 11 is the best known local LyC leaking galaxy, providing an important opportunity to test our understanding of LyC escape. The observed LyC emission in this galaxy presumably originates from one of the three bright, photoionizing knots known as A, B, and C. It is known that Knot C has strong Ly$\alpha$ emission, and Knot B hosts an unusually bright ultraluminous X-ray source, which may be a low-luminosity AGN. To clarify the LyC source, we carry out ionization-parameter mapping (IPM) by obtaining narrow-band imaging from the Hubble Space Telescope WFC3 and ACS cameras to construct spatially resolved ratio maps of [OIII]/[OII] emission from the galaxy. IPM traces the ionization structure of the interstellar medium and allows us to identify optically thin regions. To optimize the continuum subtraction, we introduce a new method for determining the best continuum scale factor derived from the mode of the continuum-subtracted, image flux distribution. We find no conclusive evidence of LyC escape from Knots B or C, but instead, we identify a high-ionization region extending over at least 1 kpc from Knot A. Knot A shows evidence of an extremely young age ($\lesssim 1$ Myr), perhaps containing very massive stars ($>100$ M$_\odot$). It is weak in Ly$\alpha$, so if it is confirmed as the LyC source, our results imply that LyC emission may be independent of Ly$\alpha$ emission.