cssi/SciSciGPT-SciSciNet huggingface dataset:
Dynamic percolation of ferromagnetic regions in phase separated manganites using non-uniform electric fields

Thin films of the manganite (La 1 − yPr y ) 1 − xCa xMnO 3 exhibit dynamic phase coexistence with micrometer scale, fluid-like ferromagnetic metallic (FMM) regions interspersed in a charge-order insulating background. It has been previously reported that a uniform electric field realigns the fluid-like FMM regions due to a phenomenon similar to dielectrophoresis. Here, we report that non-uniform electric fields have a stronger effect on the FMM regions as expected from the dielectrophoresis model. The dynamic percolation of the FMM regions is observed over a wider range of temperatures compared to the results in a uniform field. Additionally, in a non-uniform electric field, the time required for dynamic percolation along the magnetic hard axis ( t B) decreased with increasing applied voltage ( V A) as a power law, V A − δ, with δ ≈ 5 while δ < 2 for a uniform electric field. Our results in a non-uniform electric field provide strong evidence in favor of the dielectrophoresis model and a unique method for manipulating micrometer-sized ferromagnetic regions using electric fields.
CHAOS IN THE TEST PARTICLE ECCENTRIC KOZAI-LIDOV MECHANISM

The Kozai-Lidov mechanism can be applied to a vast variety of astrophysical systems involving hierarchical three-body systems. Here, we study the Kozai-Lidov mechanism systematically in the test particle limit at the octupole level of approximation. We investigate the chaotic and quasi-periodic orbital evolution by studying the surfaces of section and the Lyapunov exponents. We find that the resonances introduced by the octupole level of approximation cause orbits to flip from prograde to retrograde and back as well as cause significant eccentricity excitation, and chaotic behavior occurs when the mutual inclination between the inner and the outer binary is high. We characterize the parameter space that allows large amplitude oscillations in eccentricity and inclination.
Principles of an atomtronic transistor

A semiclassical formalism is used to investigate the transistor-like behavior of ultracold atoms in a triple-well potential. Atom current flows from the source well, held at fixed chemical potential and temperature, into an empty drain well. In steady-state, the gate well located between the source and drain is shown to acquire a well-defined chemical potential and temperature, which are controlled by the relative height of the barriers separating the three wells. It is shown that the gate chemical potential can exceed that of the source and have a lower temperature. In electronics terminology, the source–gate junction can be reverse-biased. As a result, the device exhibits regimes of negative resistance and transresistance, indicating the presence of gain. Given an external current input to the gate, transistor-like behavior is characterized both in terms of the current gain, which can be greater than unity, and the power output of the device.
Deep neural network approach for annual luminance simulations

Annual luminance maps provide meaningful evaluations for occupants’ visual comfort and perception. This paper presents a novel data-driven approach for predicting annual luminance maps from a limit...
Simultaneous construction of hyperbolic isometries

Given isometric actions by a group G on finitely many \delta-hyperbolic metric spaces, we provide a sufficient condition that guarantees the existence of a single element in G that is hyperbolic for each action. As an application we prove a conjecture of Handel and Mosher regarding relatively fully irreducible subgroups and elements in the outer automorphism group of a free group.
Testing the Formation Scenarios of Binary Neutron Star Systems with Measurements of the Neutron Star Moment of Inertia

Two low mass neutron stars, J0737-3039B and the companion to J1756-2251, show strong evidence of being formed from the collapse of an ONeMg core in an electron capture supernova (ECSN) or in an ultra-stripped iron core collapse supernova (FeCCSN). Using three different systematically generated sets of equations of state we explore the relationship between the moment of inertia of J0737-3039A and the binding energy of the two low mass neutron stars. We find this relationship, a less strict variant of the recently discovered I-Love-Q relations, is nevertheless more robust than a previously explored correlation between the binding energy and the slope of the nuclear symmetry energy L. We find that, if either J0737-3039B or the J1756-2251 companion were formed in an ECSN, no more than 0.06 solar masses could have been lost from the progenitor core, more than four times the mass loss predicted by current supernova modeling. A measurement of the moment of inertia of J0737-3039A to within 10% accuracy from pulsar timing, possible within a decade, can discriminate between formation scenarios such as ECSN or ultra-stripped FeCCSN and, given current constraints on the predicted core mass loss, potentially rule them out. Using the I-Love-Q relations we find that an Advanced LIGO can potentially measure the neutron star tidal polarizability to equivalent accuracy in a neutron star-neutron star merger at a distance of 200 Mpc, thus obtaining similar constraints on the formation scenarios. Such information on the occurrence of ECSNe is important for population synthesis calculations, especially for estimating the rate of binary neutron star mergers and resulting electromagnetic and gravitational wave signals. Further progress needs to be made modeling the core collapse process that leads to low-mass neutron stars, particularly in making robust predictions for the mass loss from the progenitor core.
HEAVY DIQUARK SYMMETRY CONSTRAINTS FOR STRONG DECAYS

The heavy diquark symmetry (HDS) of doubly heavy baryons (DHBs) provides new insights into the spectroscopy of these hadrons. We derive the consequences of this symmetry for the mass spectra and the decay widths of DHBs. We compare these symmetry constraints to results from a nonrelativistic quark model for the mass spectra and results from the 3P0 model for strong decays. The quark model we implement was not constructed with these symmetries and contains interactions which explicitly break HDS. Nevertheless these symmetries emerge. We argue that the 3P0 model and any other model for strong transitions which employs a spectator assumption explicitly respects HDS. We also explore the possibility of treating the strange quark as a heavy quark and apply these ideas to Ξ, Ξc and Ξb baryons.
Weibel Filament Decay and Thermalization in Collisionless Shocks and Gamma-Ray Burst Afterglows

Models for the synchrotron emission of gamma-ray burst afterglows suggest that the magnetic field is generated in the shock wave that forms as relativistic ejecta plow through the circumburst medium. Transverse Weibel instability efficiently generates magnetic fields near equipartition with the postshock energy density. The detailed saturated state of the instability, as seen in particle-in-cell simulations, consists of magnetically self-pinched current filaments. The filaments are parallel to the direction of propagation of the shock and are about a plasma skin depth in radius, forming a quasi-two-dimensional structure. We argue that the Weibel filaments are susceptible to pressure-driven instabilities and use a rudimentary analytical model to illustrate the development of a particular, kinklike unstable mode. The instabilities destroy the quasi-two-dimensional structure of the Weibel filaments. For wavelengths longer than the skin depth, the kinklike mode grows at the rate equal to the speed of light divided by the wavelength. We calculate the transport of collisionless test particles in the filaments experiencing the instability and show that the particles diffuse in energy. This diffusion marks the beginning of thermalization in the shock transition layer and causes initial magnetic field decay as particles escape from the filaments. We discuss the implications of these results for the structure of the shock and the polarization of the afterglow.
The Formation Rate of Blue Stragglers in 47 Tucanae

We investigate the effects of changes in the blue straggler formation rate in globular clusters on the blue straggler distribution in the color-magnitude diagram. We find that the blue straggler distribution is highly sensitive to the past formation rate. Comparison of our models to new UBV observations of a region close to the core of 47 Tucanae suggests that this cluster may have stopped forming blue stragglers several Gyr ago. This cessation of formation can be associated with an epoch of primordial binary burning which has been invoked in other clusters to infer the imminence of core collapse.
Enhanced stability of skyrmions in two-dimensional chiral magnets with rashba spin-orbit coupling

Skyrmions are complex, topological patterns that arise in magnetic materials. Researchers show that spin-orbit coupling in two dimensions stabilizes skyrmions.
Analysis of Multivariate Scoring Functions for Automatic Unbiased Learning to Rank

Leveraging biased click data for optimizing learning to rank systems has been a popular approach in information retrieval. Because click data is often noisy and biased, a variety of methods have been proposed to construct unbiased learning to rank (ULTR) algorithms for the learning of unbiased ranking models. Among them, automatic unbiased learning to rank (AutoULTR) algorithms that jointly learn user bias models (i.e., propensity models) with unbiased rankers have received a lot of attention due to their superior performance and low deployment cost in practice. Despite their differences in theories and algorithm design, existing studies on ULTR usually use uni-variate ranking functions to score each document or result independently. On the other hand, recent advances in context-aware learning-to-rank models have shown that multivariate scoring functions, which read multiple documents together and predict their ranking scores jointly, are more powerful than uni-variate ranking functions in ranking tasks with human-annotated relevance labels. Whether such superior performance would hold in ULTR with noisy data, however, is mostly unknown. In this paper, we investigate existing multivariate scoring functions and AutoULTR algorithms in theory and prove that permutation invariance is a crucial factor that determines whether a context-aware learning-to-rank model could be applied to existing AutoULTR framework. Our experiments with synthetic clicks on two large-scale benchmark datasets show that AutoULTR models with permutation-invariant multivariate scoring functions significantly outperform those with uni-variate scoring functions and permutation-variant multivariate scoring functions.
LATE-TIME CIRCUMSTELLAR INTERACTION IN A SPITZER SELECTED SAMPLE OF TYPE IIn SUPERNOVAE

Type IIn supernovae (SNe IIn) are a rare (<10%) subclass of core-collapse SNe that exhibit relatively narrow emission lines from a dense, pre-existing circumstellar medium (CSM). In 2009, a warm Spitzer Space Telescope survey observed 30 SNe IIn discovered in 2003-2008 and detected 10 SNe at distances out to 175 Mpc with unreported late-time infrared emission, in some cases more than 5 yr post-discovery. For this single epoch of data, the warm-dust parameters suggest the presence of a radiative heating source consisting of optical and X-ray emission continuously generated by ongoing CSM interaction. Here we present multi-wavelength follow-up observations of this sample of 10 SNe IIn and the well-studied Type IIn SN 2010jl. A recent epoch of Spitzer observations reveals ongoing mid-infrared emission from nine of the SNe in this sample. We also detect three of the SNe in archival Wide-field Infrared Survey Explorer data, in addition to SNe 1987A, 2004dj, and 2008iy. For at least five of the SNe in the sample, optical and/or X-ray emission confirms the presence of radiative emission from ongoing CSM interaction. The two Spitzer nondetections are consistent with the forward shock overrunning and destroying the dust shell, a result that places upper limits on the dust-shell size. The optical and infrared observations confirm the radiative heating model and constrain a number of model parameters, including progenitor mass-loss characteristics. All of the SNe in this sample experienced an outburst on the order of tens to hundreds of years prior to the SN explosion followed by periods of less intense mass loss. Although all evidence points to massive progenitors, the variation in the data highlights the diversity in SN IIn progenitor evolution. While these observations do not identify a particular progenitor system, they demonstrate that future, coordinated, multi-wavelength campaigns can constrain theoretical mass-loss models.
How the Solar Wind Ties to Its Photospheric Origins

We present a new method of visualizing the solar photospheric magnetic field based on the "Magnetic Range of Influence" (MRoI). The MRoI is a simple realization of the magnetic environment in the photosphere, reflecting the distance required to balance the integrated magnetic field contained in any magnetogram pixel. It provides a new perspective on where subterrestrial field lines in a Potential Field Source Surface (PFSS) model connect to the photosphere, and thus the source of Earth-directed solar wind (within the limitations of PFSS models), something that is not usually obvious from a regular synoptic magnetogram. In each of three sample solar rotations, at different phases of the solar cycle, the PFSS footpoint either jumps between isolated areas of high MRoI or moves slowly within one such area. Footpoint motions are consistent with Fisk's interchange reconnection model.
LATE-TIME RADIO EMISSION FROM X-RAY-SELECTED TIDAL DISRUPTION EVENTS

We present new observations with the Karl G. Jansky Very Large Array of seven X-ray-selected tidal disruption events (TDEs). The radio observations were carried out between 9 and 22 years after the initial X-ray discovery, and thus probe the late-time formation of relativistic jets and jet interactions with the interstellar medium in these systems. We detect a compact radio source in the nucleus of the galaxy IC 3599 and a compact radio source that is a possible counterpart to RX J1420.4+5334. We find no radio counterparts for five other sources with flux density upper limits between 51 and 200 {mu}Jy (3{sigma}). If the detections truly represent late radio emission associated with a TDE, then our results suggest that a fraction, {approx}> 10%, of X-ray-detected TDEs are accompanied by relativistic jets. We explore several models for producing late radio emission, including interaction of the jet with gas in the circumnuclear environment (blast wave model), and emission from the core of the jet itself. Upper limits on the radio flux density from archival observations suggest that the jet formation may have been delayed for years after the TDE, possibly triggered by the accretion rate dropping below a critical threshold of {approx}10{sup -2}-10{supmore » -3} M-dot {sub Edd}. The non-detections are also consistent with this scenario; deeper radio observations can determine whether relativistic jets are present in these systems. The emission from RX J1420.4+5334 is also consistent with the predictions of the blast wave model; however, the radio emission from IC 3599 is substantially underluminous, and its spectral slope is too flat, relative to the blast wave model expectations. Future radio monitoring of IC 3599 and RX J1420.4+5334 will help to better constrain the nature of the jets in these systems.« less
Efficiently sampling conformations and pathways using the concurrent adaptive sampling (CAS) algorithm

Molecular dynamics simulations are useful in obtaining thermodynamic and kinetic properties of bio-molecules, but they are limited by the time scale barrier. That is, we may not obtain properties' efficiently because we need to run microseconds or longer simulations using femtosecond time steps. To overcome this time scale barrier, we can use the weighted ensemble (WE) method, a powerful enhanced sampling method that efficiently samples thermodynamic and kinetic properties. However, the WE method requires an appropriate partitioning of phase space into discrete macrostates, which can be problematic when we have a high-dimensional collective space or when little is known a priori about the molecular system. Hence, we developed a new WE-based method, called the "Concurrent Adaptive Sampling (CAS) algorithm," to tackle these issues. The CAS algorithm is not constrained to use only one or two collective variables, unlike most reaction coordinate-dependent methods. Instead, it can use a large number of collective variables and adaptive macrostates to enhance the sampling in the high-dimensional space. This is especially useful for systems in which we do not know what the right reaction coordinates are, in which case we can use many collective variables to sample conformations and pathways. In addition, a clustering technique based on the committor function is used to accelerate sampling the slowest process in the molecular system. In this paper, we introduce the new method and show results from two-dimensional models and bio-molecules, specifically penta-alanine and a triazine trimer.
Strong orientational coordinates and orientational order parameters for symmetric objects

Recent advancements in the synthesis of anisotropic macromolecules and nanoparticles have spurred an immense interest in theoretical and computational studies of self-assembly. The cornerstone of such studies is the role of shape in self-assembly and in inducing complex order. The problem of identifying different types of order that can emerge in such systems can, however, be challenging. Here, we revisit the problem of quantifying orientational order in systems of building blocks with non-trivial rotational symmetries. We first propose a systematic way of constructing orientational coordinates for such symmetric building blocks. We call the arising tensorial coordinates strong orientational coordinates (SOCs) as they fully and exclusively specify the orientation of a symmetric object. We then use SOCs to describe and quantify local and global orientational order, and spatiotemporal orientational correlations in systems of symmetric building blocks. The SOCs and the orientational order parameters developed in this work are not only useful in performing and analyzing computer simulations of symmetric molecules or particles, but can also be utilized for the efficient storage of rotational information in long trajectories of evolving many-body systems.
ORBITAL PERIODS FOR THREE RECURRENT NOVAE

I report on the discovery of the orbital periods of three recurrent novae in our Galaxy. V745 Sco has an orbital period of 510 ± 20 days with ellipsoidal modulations, based on SMARTS photometry from 2004-2008. V3890 Sgr has an orbital period of 519.7 ± 0.3 days with ellipsoidal modulations and a shallow eclipse, based primarily on SMARTS and AAVSO photometry from 1995-2008, but also extending back to 1899 with archival plates. In addition, a sinusoidal modulation of amplitude 0.2 mag and period 103.8 ± 0.4 days is seen mainly in the red, with this attributed to ordinary pulsations in the giant companion star. V394 CrA has an orbital period equal to twice its primary photometric period (P orb = 1.515682 ± 0.000008 days), as based on photometry extending from 1989-2008. I use all available information (including the UBVRIJHK spectral energy distributions) to get distances to the four RNe with red giant companions as 800 ± 140 pc for T CrB, 4300 ± 700 pc for RS Oph, 7300 ± 1200 pc for V745 Sco, and 6000 ± 1000 pc for V3890 Sgr. Further, the red giant in the RS Oph system has a mass-loss rate of close to 3.7 × 10–8 M ☉ yr–1 as based on many confident measures, and this is too weak (by a factor of 100,000) to supply the white dwarf with mass at the known rate of 3.9 × 10–6 M ☉ yr–1. Thus, the only way to get matter onto the white dwarf fast enough is through Roche lobe overflow, and this confidently demonstrates that the distance to RS Oph is 3000 pc.
Topological flat bands in frustrated kagome lattice CoSn.

Electronic flat bands in momentum space, arising from strong localization of electrons in real space, are an ideal stage to realize strongly-correlated phenomena. Theoretically, the flat bands can naturally arise in certain geometrically frustrated lattices, often with nontrivial topology if combined with spin-orbit coupling. Here, we report the observation of topological flat bands in frustrated kagome metal CoSn, using angle-resolved photoemission spectroscopy and band structure calculations. Throughout the entire Brillouin zone, the bandwidth of the flat band is suppressed by an order of magnitude compared to the Dirac bands originating from the same orbitals. The frustration-driven nature of the flat band is directly confirmed by the chiral d-orbital texture of the corresponding real-space Wannier functions. Spin-orbit coupling opens a large gap of 80 meV at the quadratic touching point between the Dirac and flat bands, endowing a nonzero Z2 invariant to the flat band. These findings demonstrate that kagome-derived flat bands are a promising platform for novel emergent phases of matter at the confluence of strong correlation and topology. The experimental realization of lattice-born flat bands with nontrivial topology has been elusive. Here, the authors observe topological flat bands near the Fermi level in a kagome metal CoSn, with flat bands as well as Dirac bands originating from 3d orbitals in a frustrated kagome geometry.
Ab Initio Horizon-scale Simulations of Magnetically Arrested Accretion in Sagittarius A* Fed by Stellar Winds

We present 3D general relativistic magnetohydrodynamic (GRMHD) simulations of the accretion flow surrounding Sagittarius A* that are initialized using larger-scale MHD simulations of the $\sim$ 30 Wolf--Rayet (WR) stellar winds in the Galactic center. The properties of the resulting accretion flow on horizon scales are set not by ad hoc initial conditions but by the observationally constrained properties of the WR winds with limited free parameters. For this initial study we assume a non-spinning black hole. Our simulations naturally produce a $\sim 10^{-8} M_\odot$ yr$^{-1}$ accretion rate, consistent with previous phenomenological estimates. We find that a magnetically arrested flow is formed by the continuous accretion of coherent magnetic field being fed from large radii. Near the event horizon, the magnetic field is so strong that it tilts the gas with respect to the initial angular momentum and concentrates the originally quasi-spherical flow to a narrow disk-like structure. We also present 230 GHz images calculated from our simulations where the inclination angle and physical accretion rate are not free parameters but are determined by the properties of the WR stellar winds. The image morphology is highly time variable. Linear polarization on horizon scales is coherent with weak internal Faraday rotation.
Measurement of the Spin-Orbit Misalignment of KOI-13.01 from its Gravity-Darkened Kepler Transit Lightcurve

We model the asymmetry of the KOI-13.01 transit lightcurve assuming a gravity-darkened rapidly rotating host star in order to constrain the system's spin-orbit alignment and transit parameters. We find that our model can reproduce the Kepler lightcurve for KOI-13.01 with a sky-projected alignment of λ = 23° ± 4° and with the star's north pole tilted away from the observer by 48° ± 4° (assuming M * = 2.05 M☉). With both these determinations, we calculate that the net misalignment between this planet's orbit normal and its star's rotational pole is 56° ± 4°. Degeneracies in our geometric interpretation also allow a retrograde spin-orbit angle of 124° ± 4°. This is the first spin-orbit measurement to come from gravity darkening and is one of only a few measurements of the full (not just the sky-projected) spin-orbit misalignment of an extrasolar planet. We also measure accurate transit parameters incorporating stellar oblateness and gravity darkening: R * = 1.756 ± 0.014 R☉, R p = 1.445 ± 0.016 RJup, and i = 859 ± 04. The new lower planetary radius falls within the planetary mass regime for plausible interior models for the transiting body. A simple initial calculation shows that KOI-13.01's circular orbit is apparently inconsistent with the Kozai mechanism having driven its spin-orbit misalignment; planet-planet scattering and stellar spin migration remain viable mechanisms. Future Kepler data will improve the precision of the KOI-13.01 transit lightcurve, allowing more precise determination of transit parameters and the opportunity to use the Photometric Rossiter-McLaughlin effect to resolve the prograde/retrograde orbit determination degeneracy.
Toric degenerations and symplectic geometry of smooth projective varieties

Let $X$ be an $n$-dimensional smooth complex projective variety embedded in $\mathbb{C}\mathbb{P}^{N}$. We construct a smooth family $\mathcal{X}$ over $\mathbb{C}$ with an embedding in $\mathbb{C}\mathbb{P}^{N} \times \mathbb{C}$ whose generic fiber is $X$ and the special fiber is the torus $(\mathbb{C}^*)^n$ sitting in $\mathbb{C}\mathbb{P}^{N}$ via a monomial embedding. We use this to show that if $\omega$ is an integral Kahler form on $X$ then for any $\epsilon > 0$ there is an open subset $U_\epsilon \subset X$ such that $vol(X \setminus U_\epsilon) < \epsilon$ and $U_\epsilon$ is symplectomorphic to $(\mathbb{C}^*)^n$ equipped with a (rational) toric Kahler form. As an application we obtain lower bounds for the Gromov width of $(X, \omega)$ in terms of its associated Newton-Okounkov bodies. We also show that if $\omega$ lies in the class $c_1(L)$ of a very ample line bundle $L$ then $(X, \omega)$ has a full symplectic packing with $d$ equal balls where $d$ is the degree of $(X, L)$.
An Innovative Method for Dynamic Characterization of Fan Filter Unit Operation

Fan filter units (FFU) are widely used to deliver re-circulated air while providing filtration control of particle concentration in controlled environments such as cleanrooms, minienvironments, and operating rooms in hospitals. The objective of this paper is to document an innovative method for characterizing operation and control of an individual fan filter unit within its operable conditions. Built upon the draft laboratory method previously published [1] , this paper presents an updated method including a testing procedure to characterize dynamic operation of fan filter units, i.e., steady-state operation conditions determined by varied control schemes, airflow rates, and pressure differential across the units. The parameters for dynamic characterization include total electric power demand, total pressure efficiency, airflow rate, pressure differential across fan filter units, and airflow uniformity.
A New cosmological constant model

We propose a new cosmological model with a time-dependent cosmological constant (Λ∝1/t2), which starting at the Planck time as , evolves to the present-day allowed value of . This scenario is supported by noncritical string theory considerations. We compute the age of the Universe and the time dependence of the scale factor in this model, and find general agreement with recent determinations of the Hubble parameter for substantial values of ΩΛ. This effectively low-density open Universe model differs from the traditional cosmological constant model, and has observable implications for particle physics and cosmology.
A Tale of Two Impostors: SN2002kg and SN1954J in NGC 2403

We describe new results on two supernova impostors in NGC 2403, SN 1954J(V12) and SN 2002kg(V37). For the famous object SN 1954J, we combine four critical observations: its current SED, its Hα emission line profile, the Ca II triplet in absorption in its red spectrum, and the brightness compared to its pre-event state. Together, these strongly suggest that the survivor is now a hot supergiant with T ~ 20,000 K, a dense wind, substantial circumstellar extinction, and a G-type supergiant companion. The hot star progenitor of V12's giant eruption was likely in the post-red supergiant stage and had already shed a lot of mass. V37 is a classical LBV/S Dor variable. Our photometry and spectra observed during and after its eruption show that its outburst was an apparent transit on the HR Diagram due to enhanced mass loss and the formation of a cooler, dense wind. V37 is an evolved hot supergiant at ≈10^6 L⊙ with a probable initial mass of 60–80 M⊙.
Polarization forces in the vicinity of nanoparticles in weakly ionized plasma

It is shown that the polarization forces in a weakly ionized plasma lead to a substantial increase in the fluxes of neutral atoms and molecules to the surface of charged nanoparticles. Thus, the nanoparticles can change the thermal balance due to the acceleration of atoms and molecules in the dipole potential and subsequent inelastic collisions to the nanoparticles.
Spinodal decomposition in high temperature gauge theories

Abstract After a rapid increase in temperature across the deconfinement temperature T d , pure gauge theories exhibit unstable long wavelength fluctuations in the approach to equilibrium. This phenomenon is analogous to spinodal decomposition observed in condensed matter physics, and also seen in models of disordered chiral condensate formation. At high temperature, the unstable modes occur only in the range 0≤ k ≤ k c , where k c is on the order of the Debye screening mass m D . Equilibration always occurs via spinodal decomposition for SU(2) at temperatures T > T d and for SU (3) for T ≫ T d . For SU (3) at temperatures T ≳ T d , nucleation may replace spinodal decomposition as the dominant equilibration mechanism. Monte Carlo simulations of SU (2) lattice gauge theory exhibit the predicted phenomena. The observed value of k c is in reasonable agreement with a value predicted from previous lattice measurements of m D .
A coarse-grained deep neural network model for liquid water

We introduce a coarse-grained deep neural network (CG-DNN) model for liquid water that utilizes 50 rotational and translational invariant coordinates and is trained exclusively against energies of ∼30 000 bulk water configurations. Our CG-DNN potential accurately predicts both the energies and the molecular forces of water, within 0.9 meV/molecule and 54 meV/A of a reference (coarse-grained bond-order potential) model. The CG-DNN water model also provides good prediction of several structural, thermodynamic, and temperature dependent properties of liquid water, with values close to those obtained from the reference model. More importantly, CG-DNN captures the well-known density anomaly of liquid water observed in experiments. Our work lays the groundwork for a scheme where existing empirical water models can be utilized to develop a fully flexible neural network framework that can subsequently be trained against sparse data from high-fidelity albeit expensive beyond-DFT calculations.We introduce a coarse-grained deep neural network (CG-DNN) model for liquid water that utilizes 50 rotational and translational invariant coordinates and is trained exclusively against energies of ∼30 000 bulk water configurations. Our CG-DNN potential accurately predicts both the energies and the molecular forces of water, within 0.9 meV/molecule and 54 meV/A of a reference (coarse-grained bond-order potential) model. The CG-DNN water model also provides good prediction of several structural, thermodynamic, and temperature dependent properties of liquid water, with values close to those obtained from the reference model. More importantly, CG-DNN captures the well-known density anomaly of liquid water observed in experiments. Our work lays the groundwork for a scheme where existing empirical water models can be utilized to develop a fully flexible neural network framework that can subsequently be trained against sparse data from high-fidelity albeit expensive beyond-DFT calculations.
Self-pulsation in fiber-coupled, on-chip microcavity lasers

We report self-pulsation in an erbium-doped silica toroidal microcavity laser coupled to a tapered fiber and investigate the effects of pump power and taper-cavity coupling condition on the dynamic behaviors of the pulse train. The microcavity is pumped at 1444.8 nm, and lasing occurs at 1560.2 nm with a threshold of 12 μW. Experimental results are interpreted within the framework of ion-pair induced self-quenching model.
Three dimensional pure gravity and generalized Hecke operators

In this paper, we study mathematical functions of relevance to pure gravity in AdS3. Modular covariance places stringent constraints on the space of such functions; modular invariance places even stronger constraints on how they may be combined into physically viable candidate partition functions. We explicitly detail the list of holomorphic and anti-holomorphic functions that serve as candidates for chiral and anti-chiral partition functions and note that modular covariance is only consistent with such functions when the left (resp. right) central charge is an integer multiple of 8, c ∈ 8ℕ. We then find related constraints on the symmetry group of the corresponding topological, Chern-Simons, theory in the bulk of AdS. The symmetry group of the theory can be one of two choices: either SO(2; 1) × SO(2; 1) or its three-fold diagonal cover. We introduce the generalized Hecke operators which map the modular covariant functions to the modular covariant functions. With these mathematical results, we obtain conjectural partition functions for extremal CFT2s, and the corresponding microcanonical entropies, when the chiral central charges are multiples of eight. Finally, we compute subleading corrections to the Beckenstein-Hawking entropy in the bulk gravitational theory with these conjectural partition functions.
Non-thermalization in trapped atomic ion spin chains.

Linear arrays of trapped and laser-cooled atomic ions are a versatile platform for studying strongly interacting many-body quantum systems. Effective spins are encoded in long-lived electronic leve...
Minimax rational approximation of the Fermi-Dirac distribution

Accurate rational approximations of the Fermi-Dirac distribution are a useful component in many numerical algorithms for electronic structure calculations. The best known approximations use O(log(βΔ)log(ϵ−1)) poles to achieve an error tolerance ϵ at temperature β−1 over an energy interval Δ. We apply minimax approximation to reduce the number of poles by a factor of four and replace Δ with Δocc, the occupied energy interval. This is particularly beneficial when Δ ≫ Δocc, such as in electronic structure calculations that use a large basis set.
Strong correlation effects and optical conductivity in electron-doped cuprates

We demonstrate that most features ascribed to strong correlation effects in various spectroscopies of the electron-doped cuprates are captured by a calculation of the self-energy incorporating effects of spin and charge fluctuations. The self-energy is calculated over the full doping range of electron-doped cuprates from half filling to the overdoped system. The self-energy devides the low-energy physics of cuprates into two energy scales: an antiferromagnetic (AFM) "pseudogap" region near the Fermi level and a high-energy "Mott gap region". The corresponding spectral function reveals four subbands, two widely split incoherent bands representing the remnant of the split Hubbard bands, and two additional coherent, spin- and charge-dressed in-gap bands split by a spin-density-wave, which collapses in the overdoped regime. The incoherent features persist to high doping, producing a remnant Mott gap in the optical spectra, while transitions between the in-gap states lead to AFM pseudogap features in the mid-infrared.
CRYSTAL ENERGY FUNCTIONS VIA THE CHARGE IN TYPES A AND C

The Ram–Yip formula for Macdonald polynomials (at t = 0) provides a statistic which we call charge. In types A and C it can be defined on tensor products of Kashiwara–Nakashima single column crystals. In this paper we prove that the charge is equal to the (negative of the) energy function on affine crystals. The algorithm for computing charge is much simpler and can be more efficiently computed than the recursive definition of energy in terms of the combinatorial R-matrix.
On Quantified Modal Theorem Proving for Modeling Ethics

In the last decade, formal logics have been used to model a wide range of ethical theories and principles with the goal of using these models within autonomous systems. Logics for modeling ethical theories, and their automated reasoners, have requirements that are different from modal logics used for other purposes, e.g. for temporal reasoning. Meeting these requirements necessitates investigation of new approaches for proof automation. Particularly, a quantified modal logic, the deontic cognitive event calculus (DCEC), has been used to model various versions of the doctrine of double effect, akrasia, and virtue ethics. Using a fragment of DCEC, we outline these distinct characteristics and present a sketches of an algorithm that can help with some aspects proof automation for DCEC.
Tail approximations of integrals of Gaussian random fields

This paper develops asymptotic approximations of P(∫Tef(t) dt > b) as b → ∞ for a homogeneous smooth Gaussian random field, f, living on a compact d-dimensional Jordan measurable set T. The integral of an exponent of a Gaussian random field is an important random variable for many generic models in spatial point processes, portfolio risk analysis, asset pricing and so forth. The analysis technique consists of two steps: 1. evaluate the tail probability P(∫Ξef(t) dt > b) over a small domain Ξ depending on b, where mes(Ξ) → 0 as b → ∞ and mes(⋅) is the Lebesgue measure; 2. with Ξ appropriately chosen, we show that P(∫Tef(t) dt > b) = (1 + o(1)) mes(T) mes−1(Ξ) P(∫Ξef(t) dt > b).
Time Variable Broad-line Emission in NGC 4203: Evidence for Stellar Contrails

Dual epoch spectroscopy of the lenticular galaxy, NGC 4203, obtained with the Hubble Space Telescope has revealed that the double-peaked component of the broad Hα emission line is time variable, increasing by a factor of 2.2 in brightness between 1999 and 2010. Modeling the gas distribution responsible for the double-peaked profiles indicates that a ring is a more appropriate description than a disk and most likely represents the contrail of a red supergiant star that is being tidally disrupted at a distance of ~1500 AU from the central black hole. There is also a bright core of broad Hα line emission that is not time variable and identified with a large-scale inflow from an outer radius of ~1 pc. If the gas number density is ≥106 cm–3, as suggested by the absence of similarly broad [O I] and [O III] emission lines, then the steady state inflow rate is ~ 2 × 10–2 M ☉ yr–1, which exceeds the inflow requirement to explain the X-ray luminosity in terms of radiatively inefficient accretion by a factor of ~6. The central active galactic nucleus (AGN) is unable to sustain ionization of the broad-line region; the discrepancy is particularly acute in 2010 when the broad Hα emission line is dominated by the contrail of the infalling supergiant star. However, ram pressure shock ionization produced by the interaction of the infalling supergiant with the ambient interstellar medium may help alleviate the ionizing deficit by generating a mechanical source of ionization supplementing the photoionization provided by the AGN.
Nuclear Star Clusters in Cosmological Simulations

We investigate the possible connection between the most massive globular clusters, such as $\omega$ Cen and M54, and nuclear star clusters of dwarf galaxies that exhibit similar spreads in age and metallicity. We examine galactic nuclei in cosmological galaxy formation simulations at $z \approx 1.5$ to explore whether their age and metallicity spreads could explain these massive globular clusters. We derive structural properties of these nuclear regions, including mass, size, rotation, and shape. By using theoretical supernova yields to model the supernova enrichment in the simulations, we obtain individual elemental abundances for Fe, O, Na, Mg, and Al. Our nuclei are systematically more metal-rich than their host galaxies, which lie on the expected mass-metallicity relation. Some nuclei have a spread in Fe and age comparable to the massive globular clusters of the Milky Way, lending support to the hypothesis that nuclear star clusters of dwarf galaxies could be the progenitors of these objects. None of our nuclear regions contain the light element abundance spreads that characterize globular clusters, even when a large age spread is present. Our results demonstrate that extended star formation history within clusters, with metal pollution provided solely by supernova ejecta, is capable of replicating the metallicity spreads of massive globular clusters, but still requires another polluter to produce the light element variations.
A Diagram for Bianchi A-Types

A diagram for Bianchi spaces with vanishing vector of structure constants (type A in the Ellis-MacCallum classification) illustrates the relations among their different types under similarity transformations. The Ricci coefficients and the Ricci tensor are related by a Cremona transformation.
REMARKS ON CONGRUENCE OF 3-MANIFOLDS

We give two proofs that the 3-torus is not weakly d-congruent to #3S1 × S2, if d > 2. We study how cohomology ring structure relates to weak congruence. We give an example of three 3-manifolds which are weakly 5-congruent but are not 5-congruent.
Multivariable polynomial injections on rational numbers

For each number field k, the Bombieri-Lang conjecture for k-rational points on surfaces of general type implies the existence of a polynomial f(x,y) in k[x,y] inducing an injection k x k --> k.
Nonlinear electrostatics: steps towards a neoclassical electron model

The basic approach was to start with the field of the electron as the fundamental object of study, and then attempt to derive the charge and mass from its various properties. In particular, the charge could be obtained by integrating the flux density of the field over any closed orientable surface that enclosed the source of the field and the rest mass would presumably be due to the total self-energy of the field. It was in the latter construction that the classical electron models ran into difficulties. Either the source charge distribution for the electron was pointlike or it was spatially extended, and most likely spherical, due to the symmetry of the field. Although a pointlike electron satisfied the requirement of stability, nevertheless, it suffered from an infinite self-energy. Whereas an extended charge distribution, such as a spherical ball or shell of a finite, but small, radius produced a finite self-energy, nonetheless, if Coulomb’s law of electrostatics was still in effect at those distances, it would be difficult to explain the stability of the charge distribution under the mutual repulsion of its constituent charge elements. The resulting figure for the classical electron radius rc was obtained by equating the rest energy of the mass to the total potential energy of the field:
Constraints on Dark Matter Microphysics from the Milky Way Satellite Population

Alternatives to the cold, collisionless dark matter (DM) paradigm in which DM behaves as a collisional fluid generically suppress small-scale structure. Herein we use the observed population of Milky Way (MW) satellite galaxies to constrain the collisional nature of DM, focusing on DM-baryon scattering. We first derive analytic upper limits on the velocity-independent DM-baryon scattering cross section by translating the upper bound on the lowest mass of halos inferred to host satellites into a characteristic cutoff scale in the linear matter power spectrum. We then confirm and improve these results through a detailed probabilistic inference of the MW satellite population that marginalizes over relevant astrophysical uncertainties. This yields $95\%$ confidence upper limits on the DM-baryon scattering cross section of $2\times10^{-29}\ \rm{cm}^2$ ($6\times 10^{-27}\ \rm{cm}^2$) for DM particle masses $m_\chi$ of~$10\ \rm{keV}$ ($10\ \rm{GeV}$); these limits scale as $m_\chi^{1/4}$ for $m_\chi \ll 1\ \rm{GeV}$ and $m_\chi$ for~$m_\chi \gg 1\ \rm{GeV}$. This analysis improves upon cosmological bounds derived from cosmic-microwave-background anisotropy measurements by multiple orders of magnitude over a wide range of DM masses, excluding regions of parameter space previously unexplored by other methods, including direct-detection experiments. Our work reveals a mapping between DM-baryon scattering and other alternative DM models, and we discuss the implications of our results for warm and fuzzy DM scenarios.
ColdRoute: effective routing of cold questions in stack exchange sites

Routing questions in Community Question Answer services such as Stack Exchange sites is a well-studied problem. Yet, cold-start—a phenomena observed when a new question is posted is not well addressed by existing approaches. Additionally, cold questions posted by new askers present significant challenges to state-of-the-art approaches. We propose ColdRoute to address these challenges. ColdRoute is able to handle the task of routing cold questions posted by new or existing askers to matching experts. Specifically, we use Factorization Machines on the one-hot encoding of critical features such as question tags and compare our approach to well-studied techniques such as CQARank and semantic matching (LDA, BoW, and Doc2Vec). Using data from eight stack exchange sites, we are able to improve upon the routing metrics (Precision@1, Accuracy, MRR) over the state-of-the-art models such as semantic matching by 159.5, 31.84, and 40.36% for cold questions posted by existing askers, and 123.1, 27.03, and 34.81% for cold questions posted by new askers respectively.
Deciphering the Enigma of Wave-Particle Duality

A satisfactory explanation of the confounding wave-particle duality of matter is presented in terms of the reality of the wave nature of a particle. In this view, a quantum particle is an objectively real wave packet consisting of irregular disturbances of underlying quantum fields. It travels holistically as a unit and thereby acts as a particle. Only the totality of the entire wave packet at any instance embodies all the conserved quantities, for example the energy-momentum, rest mass, and charge of the particle, and as such must be acquired all at once during detection. On this basis, many of the bizarre behaviors observed in the quantum domain, such as wave function collapse, the limitation of prediction to only a probability rather than an actuality, the apparent simultaneous existence of a particle in more than one place, and the inherent uncertainty can be reasonably comprehended. The necessity of acquiring the wave function in its entirety for detection, as evinced by the appearance of collapse of the wave function, supports the paradigm of reality of the wave function described here. Quanta 2016; 5: 93–100.