cssi/SciSciGPT-SciSciNet huggingface dataset:
Debiasing Desire: Addressing Bias & Discrimination on Intimate Platforms

Designing technical systems to be resistant to bias and discrimination represents vital new terrain for researchers, policymakers, and the anti-discrimination project more broadly. We consider bias and discrimination in the context of popular online dating and hookup platforms in the United States, which we call intimate platforms. Drawing on work in social-justice-oriented and Queer HCI, we review design features of popular intimate platforms and their potential role in exacerbating or mitigating interpersonal bias. We argue that focusing on platform design can reveal opportunities to reshape troubling patterns of intimate contact without overriding users' decisional autonomy. We identify and address the difficult ethical questions that nevertheless come along with such intervention, while urging the social computing community to engage more deeply with issues of bias, discrimination, and exclusion in the study and design of intimate platforms.
Functional Object-Oriented Network: Construction & Expansion

We build upon the functional object-oriented network (FOON), a structured knowledge representation which is constructed from observations of human activities and manipulations. A FOON can be used for representing object-motion affordances. Knowledge retrieval through graph search allows us to obtain novel manipulation sequences using knowledge spanning across many video sources, hence the novelty in our approach. However, we are limited to the sources collected. To further improve the performance of knowledge retrieval as a follow up to our previous work, we discuss generalizing knowledge to be applied to objects which are similar to what we have in FOON without manually annotating new sources of knowledge. We discuss two means of generalization: 1) expanding our network through the use of object similarity to create new functional units from those we already have, and 2) compressing the functional units by object categories rather than specific objects. We discuss experiments which compare the performance of our knowledge retrieval algorithm with both expansion and compression by categories.
Moist Adiabats with Multiple Condensing Species: A New Theory with Application to Giant-Planet Atmospheres

We derived a new formula for calculating the moist adiabatic temperature profile of an atmosphere consisting of ideal gases with multiple condensing species. This expression unifies various formulas published in the literature and can be generalized to account for chemical reactions. Unlike previous methods, it converges to machine precision independent of mesh size. It accounts for any ratio of condensable vapors to dry gas, from zero to infinity, and for variable heat capacities as a function of temperature. Because the derivation is generic, the new formula is not only applicable to planetary atmosphere in the solar system, but also to hot Jupiters and brown dwarfs in which a variety of alkali metals, silicates and exotic materials condense. We demonstrate that even though the vapors are ideal gases, they interact in their effects on the moist adiabatic lapse rate. Finally, we apply the new thermodynamic model to study the effects of downdrafts on the distribution of minor constituents and thermal profile in the Galileo probe hotspot. We find that the Galileo Probe measurements can be interpreted as a strong downdraft that displaces an air parcel from 1 bar to the 4 bar level.
MODELING THE FLYBY ANOMALIES WITH DARK MATTER SCATTERING: UPDATE WITH ADDITIONAL DATA AND FURTHER PREDICTIONS

We continue our exploration of whether the flyby anomalies can be explained by scattering of spacecraft nucleons from dark matter gravitationally bound to the Earth, with the addition of data from five new flybys to that from the original six. We continue to use our model in which inelastic and elastic scatterers populate shells generated by the precession of circular orbits with normals tilted with respect to the Earth's axis. With 11 data points and eight parameters in the model, a statistically meaningful fit is obtained with a chi-squared of 2.7. We give plots of the anomalous acceleration along the spacecraft trajectory, and the cumulative velocity change, for the five flybys which exhibit a significant nonzero anomaly. We also discuss implications of the fit for dark matter–nucleon cross-sections, give the prediction of our fit for the anomaly to be expected from the future Juno flyby, and give predictions of our fit for flyby orbit orientation changes. In addition, we give formulas for estimating the flyby temperature increase caused by dark matter inelastic scattering, and for the fraction of flyby nucleons undergoing such scatters. Finally, for circular satellite orbits, we give a table of predicted secular changes in orbit radius. These are much too large to be reasonable — comparing with data for COBE and GP-B supplied to us by Edward Wright (after the first version of this paper was posted), we find that our model predicts changes in orbit radius that are too large by many orders of magnitude. So the model studied here is ruled out. We conclude that further modeling of the flyby anomalies must simultaneously attempt to fit constraints coming from satellite orbits.
Power of Pausing: Advancing Understanding of Thermalization in Experimental Quantum Annealers

We investigate alternative annealing schedules on the current generation of quantum annealing hardware (the D-Wave 2000Q), which includes the use of forward and reverse annealing with an intermediate pause. This work provides new insights into the inner workings of these devices (and quantum devices in general), particular into how thermal effects govern the system dynamics. We show that a pause mid-way through the anneal can cause a dramatic change in the output distribution, and we provide evidence suggesting thermalization is indeed occurring during such a pause. We demonstrate that upon pausing the system in a narrow region shortly after the minimum gap, the probability of successfully finding the ground state of the problem Hamiltonian can be increased over an order of magnitude. We relate this effect to relaxation (i.e. thermalization) after diabatic and thermal excitations that occur in the region near to the minimum gap. For a set of large-scale problems of up to 500 qubits, we demonstrate that the distribution returned from the annealer very closely matches a (classical) Boltzmann distribution of the problem Hamiltonian, albeit one with a temperature at least 1.5 times higher than the (effective) temperature of the annealer. Moreover, we show that larger problems are more likely to thermalize to a classical Boltzmann distribution.
On the Convergence Analysis of the Optimized Gradient Method

This paper considers the problem of unconstrained minimization of smooth convex functions having Lipschitz continuous gradients with known Lipschitz constant. We recently proposed the optimized gradient method for this problem and showed that it has a worst-case convergence bound for the cost function decrease that is twice as small as that of Nesterov's fast gradient method, yet has a similarly efficient practical implementation. Drori showed recently that the optimized gradient method has optimal complexity for the cost function decrease over the general class of first-order methods. This optimality makes it important to study fully the convergence properties of the optimized gradient method. The previous worst-case convergence bound for the optimized gradient method was derived for only the last iterate of a secondary sequence. This paper provides an analytic convergence bound for the primary sequence generated by the optimized gradient method. We then discuss additional convergence properties of the optimized gradient method, including the interesting fact that the optimized gradient method has two types of worst-case functions: a piecewise affine-quadratic function and a quadratic function. These results help complete the theory of an optimal first-order method for smooth convex minimization.
p-adic interpolation of iterates

Extending work of Bell and of Bell, Ghioca, and Tucker, we prove that for a p-adic analytic self-map f on a closed unit polydisk, if every coefficient of f(x)-x has valuation greater than that of p^{1/(p-1)}, then the iterates of f can be p-adically interpolated; i.e., there exists a function g(x,n) analytic in both x and n such that g(x,n) = f^n(x) whenever n is a nonnegative integer.
SIMULATING DEEP HUBBLE IMAGES WITH SEMI-EMPIRICAL MODELS OF GALAXY FORMATION

We simulate deep images from the Hubble Space Telescope (HST) using semi-empirical models of galaxy formation with only a few basic assumptions and parameters. We project our simulations all the way to the observational domain, adding cosmological and instrumental effects to the images, and analyze them in the same way as real HST images (forward modeling). This is a powerful tool for testing and comparing galaxy evolution models, since it allows us to make unbiased comparisons between the predicted and observed distributions of galaxy properties, while automatically taking into account all relevant selection effects. Our semi-empirical models populate each dark matter halo with a galaxy of determined stellar mass and scale radius. We compute the luminosity and spectrum of each simulated galaxy from its evolving stellar mass using stellar population synthesis models. We calculate the intrinsic scatter in the stellar mass-halo mass relation that naturally results from enforcing a monotonically increasing stellar mass along the merger history of each halo. The simulated galaxy images are drawn from cutouts of real galaxies from the Sloan Digital Sky Survey, with sizes and fluxes rescaled to match those of the model galaxies. The distributions of galaxy luminosities, sizes, and surface brightnesses depend on the adjustable parameters in the models, and they agree well with observations for reasonable values of those parameters. Measured galaxy magnitudes and sizes have significant magnitude-dependent biases, with both being underestimated near the magnitude detection limit. The fraction of galaxies detected and fraction of light detected also depend sensitively on the details of the model.
Nonasymptotic convergence rates for cooperative learning over time-varying directed graphs

We study the problem of cooperative learning with a network of agents where some agents repeatedly access information about a random variable with unknown distribution. The group objective is to globally agree on a joint hypothesis (distribution) that best describes the observed data at all nodes. The agents interact with their neighbors in an unknown sequence of time-varying directed graphs. Following the pioneering work of Jadbabaie, Molavi, Sandroni, and Tahbaz-Salehi and others, we propose local learning dynamics which combine Bayesian updates at each node with a local aggregation rule of private agent signals. We show that these learning dynamics drive all agents to the set of hypotheses which best explain the data collected at all nodes as long as the sequence of interconnection graphs is uniformly strongly connected. Our main result establishes a non-asymptotic, explicit, geometric convergence rate for the learning dynamic.
Position Reconstruction of Bubble Formation in Liquid Nitrogen using Piezoelectric Sensors

Cryogenic liquids, particularly liquid xenon and argon, are of interest as detector media for experiments in nuclear and particle physics. Here we present a new detector diagnostic technique using piezoelectric sensors to detect bubbling of the liquid. Bubbling can indicate locations of excess heat dissipation e.g., in immersed electronics. They can also interfere with normal event evolution by scattering of light or by interrupting the drift of ionization charge. In our test apparatus, four sensors are placed in the vacuum space of a double-walled dewar of liquid nitrogen and used to detect and locate a source of bubbling inside the liquid volume. Utilizing the differences in transmitted frequencies through the different media present in the experiment, we find that sound traveling in a direct path from the source to the sensor can be isolated with appropriate filtering. The location of the source is then reconstructed using the time difference of arrivals (TDOA) information. The reconstruction algorithm is shown to have a 95.8% reproducibility rate and reconstructed positions are self-consistent to an average ±0.5 cm around the mean in x, y, and z. Systematic effects are observed to cause errors in reconstruction when bubbles occur very close to the surfaces of the liquid volume.
Hodge theory of the Goldman bracket

We show that, after completing in the I–adic topology, the Goldman bracket on the space spanned by the closed geodesics on a smooth, complex algebraic curve X is a morphism of mixed Hodge structures. We prove similar statements for the natural action of the loops in X on paths from one boundary vector to another.
Hardware trojan detection through information flow security verification

Semiconductor design houses are increasingly becoming dependent on third party vendors to procure intellectual property (IP) and meet time-to-market constraints. However, these third party IPs cannot be trusted as hardware Trojans can be maliciously inserted into them by untrusted vendors. While different approaches have been proposed to detect Trojans in third party IPs, their limitations have not been extensively studied. In this paper, we analyze the limitations of the state-of-the-art Trojan detection techniques and demonstrate with experimental results how to defeat these detection mechanisms. We then propose a Trojan detection framework based on information flow security (IFS) verification. Our framework detects violation of IFS policies caused by Trojans without the need of white-box knowledge of the IP. We experimentally validate the efficacy of our proposed technique by accurately identifying Trojans in the trust-hub benchmarks. We also demonstrate that our technique does not share the limitations of the previously proposed Trojan detection techniques.
On the Knot Floer Homology of Twisted Torus Knots

In this paper we study the knot Floer homology of a subfamily of twisted pp, qq torus knots where q ” 1 (mod p). Specifically, we classify the knots in this subfamily that admit L-space surgeries. To do calculations, we use the fact that these knots are p1, 1q knots and, therefore, admit a genus one Heegaard diagram.
Tuning quantum channels to maximize polarization entanglement for telecom photon pairs

Quantum networks entangle remote nodes by distributing quantum states, which inevitably suffer from decoherence while traversing quantum channels. Pertinent decoherence mechanisms govern the reach, quality, and rate of distributed entanglement. Hence recognizing, understanding, and modeling those mechanisms is a crucial step in building quantum networks. Here, we study real-life fiber-optic quantum channels that partially filter individual modes of transmitted polarization-entangled states and are capable of introducing dephasing. First, we theoretically model and experimentally demonstrate the combined effect of two independent and arbitrarily oriented polarization-dependent loss elements experienced by each photon of an entangled photon pair. Then, we showcase the compensation of lost entanglement by properly adjusting the channels’ properties and discuss the resulting tradeoff between the entanglement quality and rate. Our results provide insights into the robustness of fiber-optic quantum channels, thus taking an important step toward the realization of quantum networks. If one photon in an entangled pair suffers from losses common to optical fibers, it can be compensated for by using just the other photon. As quantum communication technologies approach practical applications, greater attention is being paid to issues that affect realistic devices rather than theoretical idealisations. To construct a quantum network, entanglement has to be shared between distant nodes, which is often achieved by sending entangled photon pairs to the nodes using optical cables. Daniel Jones and colleagues from the U.S. Army Research Laboratory have analysed how entangled photons are affected by polarization-dependent losses that arise in fiber optic cables due to residual imperfections and changes in their environment. They show that reductions in entanglement quality caused by losses affecting one photon can be non-locally recovered by adjusting the other photon’s propagation.
Two-dimensional infrared spectroscopy of vibrational polaritons of molecules in an optical cavity

Strong coupling of molecular vibrations to an infrared cavity mode affects their nature by creating dressed polariton states. We show how the single and double vibrational polariton manifolds may be controlled by varying the cavity coupling strength and probed by a time domain two-dimensional infrared (2DIR) technique, double quantum coherence. Applications are made to the amide-I (CO) and amide-II (CN) bond vibrations of N-methylacetamide.
Random flag complexes and asymptotic syzygies

We use the probabilistic method to construct examples of conjectured phenomena about asymptotic syzygies. In particular, we use Stanley–Reisner ideals of random flag complexes to construct new examples of Ein and Lazarsfeld’s nonvanishing for asymptotic syzygies and of Ein, Erman, and Lazarsfeld’s conjecture on how asymptotic Betti numbers behave like binomial coefficients.
A Mathematical Theory of Quantum Sheaf Cohomology

The purpose of this paper is to present a mathematical theory of the half-twisted $(0,2)$ gauged linear sigma model and its correlation functions that agrees with and extends results from physics. The theory is associated to a smooth projective toric variety $X$ and a deformation $\sheaf E$ of its tangent bundle $T_X$. It gives a quantum deformation of the cohomology ring of the exterior algebra of $\sheaf E^*$. We prove that in the general case, the correlation functions are independent of `nonlinear' deformations. We derive quantum sheaf cohomology relations that correctly specialize to the ordinary quantum cohomology relations described by Batyrev in the special case $\sheaf E = T_X$.
Understanding tables with intermediate pre-training

Table entailment, the binary classification task of finding if a sentence is supported or refuted by the content of a table, requires parsing language and table structure as well as numerical and discrete reasoning. While there is extensive work on textual entailment, table entailment is less well studied. We adapt TAPAS (Herzig et al., 2020), a table-based BERT model, to recognize entailment. Motivated by the benefits of data augmentation, we create a balanced dataset of millions of automatically created training examples which are learned in an intermediate step prior to fine-tuning. This new data is not only useful for table entailment, but also for SQA (Iyyer et al., 2017), a sequential table QA task. To be able to use long examples as input of BERT models, we evaluate table pruning techniques as a pre-processing step to drastically improve the training and prediction efficiency at a moderate drop in accuracy. The different methods set the new state-of-the-art on the TabFact (Chen et al., 2020) and SQA datasets.
The age of the universe

Abstract A minimum age of the universe can be estimated directly by determining the age of the oldest objects in our Galaxy. These objects are the metal-poor stars in the halo of the Milky Way. Recent work on nucleochronology finds that the oldest stars are 15.2±3.7 Gyr old. White dwarf cooling curves have found a minimum age for the oldest stars of 8 Gyr. Currently, the best estimate for the age of the oldest stars is based upon the absolute magnitude of the main sequence turn-off in globular clusters. The oldest globular clusters are 11.5±1.3 Gyr, implying a minimum age of the universe of t universe ≥9.5 Gyr (95% confidence level).
A conformal truncation framework for infinite-volume dynamics

We present a new framework for studying conformal field theories deformed by one or more relevant operators. The original CFT is described in infinite volume using a basis of states with definite momentum, P , and conformal Casimir, C. The relevant deformation is then considered using lightcone quantization, with the resulting Hamiltonian expressed in terms of this CFT basis. Truncating to states with $$ \mathcal{C}\le {\mathcal{C}}_{\max } $$ , one can numerically find the resulting spectrum, as well as other dynamical quantities, such as spectral densities of operators. This method requires the introduction of an appropriate regulator, which can be chosen to preserve the conformal structure of the basis. We check this framework in three dimensions for various perturbative deformations of a free scalar CFT, and for the case of a free O(N ) CFT deformed by a mass term and a non-perturbative quartic interaction at large-N . In all cases, the truncation scheme correctly reproduces known analytic results. We also discuss a general procedure for generating a basis of Casimir eigenstates for a free CFT in any number of dimensions.
Thermal transport size effects in silicon membranes featuring nanopillars as local resonators

Silicon membranes patterned by nanometer-scale pillars standing on the surface provide a practical platform for thermal conductivity reduction by resonance hybridizations. Using molecular simulations, we investigate the effects of nanopillar size, unit-cell size, and finite-structure size on the net capacity of the local resonators in reducing the thermal conductivity of the base membrane. The results indicate that the thermal conductivity reduction increases as the ratio of the volumetric size of a unit nanopillar to that of the base membrane is increased, and the intensity of this reduction varies with unit-cell size at a rate dependent on the volumetric ratio. Considering sample size, the resonance-induced thermal conductivity drop is shown to increase slightly with the number of unit cells until it would eventually level off.
Sequential Changepoint Approach for Online Community Detection

We present new algorithms for detecting the emergence of a community in large networks from sequential observations. The networks are modeled using Erdős-Renyi random graphs with edges forming between nodes in the community with higher probability. Based on statistical changepoint detection methodology, we develop three algorithms: the Exhaustive Search (ES), the Mixture, and the Hierarchical Mixture (H-Mix) methods. Performance of these methods is evaluated by the average run length (ARL), which captures the frequency of false alarms, and the detection delay. Numerical comparisons show that the ES method performs the best; however, it is exponentially complex. The Mixture method is polynomially complex by exploiting the fact that the size of the community is typically small in a large network. However, it may react to a group of active edges that do not form a community. This issue is resolved by the H-Mix method, which is based on a dendrogram decomposition of the network. We present an asymptotic analytical expression for ARL of the Mixture method when the threshold is large.
THE WORD PROBLEM AND THE METRIC FOR THE THOMPSON-STEIN GROUPS

We consider the Thompson-Stein group F(n1, ..., nk) where n1, ..., nk 2 {2,3,4, ...}, k 2 N. We highlight several differences between the cases k = 1 and k > 1, including the fact that minimal tree-pair diagram representatives of elements may not be unique when k > 1. We establish how to find minimal tree-pair diagram representatives of elements of F(n1, ..., nk), and we prove several theorems describing the equivalence of trees and tree-pair diagrams. We introduce a unique normal form for elements of F(n1, ..., nk) (with respect to the standard infinite generating set developed by Melanie Stein) which provides a solution to the word problem, and we give sharp upper and lower bounds on the metric with respect to the standard finite generating set, showing that in the case k > 1, the metric is not quasi-isometric to the number of leaves or caret in the minimal tree-pair diagram, as is the case when k = 1.
Deciding the winner of an arbitrary finite poset game is PSPACE-Complete

A poset game is a two-player game played over a partially ordered set (poset) in which the players alternate choosing an element of the poset, removing it and all elements greater than it. The first player unable to select an element of the poset loses. Polynomial time algorithms exist for certain restricted classes of poset games, such as the game of Nim. However, until recently the complexity of arbitrary finite poset games was only known to exist somewhere between NC1 and PSPACE. We resolve this discrepancy by showing that deciding the winner of an arbitrary finite poset game is PSPACE-complete. To this end, we give an explicit reduction from Node Kayles, a PSPACE-complete game in which players vie to chose an independent set in a graph.
Generic Misalignment Aberration Patterns in Wide-Field Telescopes

Axially symmetric telescopes produce well-known Seidel off-axis third-order aberration patterns: coma, astigmatism, curvature of field, and distortion. When axial symmetry is broken by the small misalignments of optical elements, additional third-order aberration patterns arise: one each for coma, astigmatism, and curvature of field and two for distortion. Each of these misalignment patterns is characterized by an associated two-dimensional vector, each of which in turn is a linear combination of the tilt and decenter vectors of the individual optical elements. For an N-mirror telescope, 2(N - 1) patterns must be measured to keep the telescope aligned. Alignment of the focal plane may require two additional patterns. For N = 3, as in a three-mirror anastigmat, there is a two-dimensional "subspace of benign misalignment" over which the misalignment patterns for third-order coma, astigmatism, and curvature of field are identically zero. One would need to measure at least one of the two distortion patterns to keep the telescope aligned. Alternatively, one might measure one of the fifth-order misalignment patterns, which are derived herein. But the fifth-order patterns are rather insensitive to misalignments, even with moderately wide fields, rendering them of relatively little use in telescope alignment. Another alternative would be to use telescope pointing as part of the alignment solution.
Dimensionless scaling of heat-release-induced planar shock waves in near-critical CO2

We performed highly resolved one-dimensional fully compressible Navier-Stokes simulations of heat-release-induced compression waves in near-critical CO2. The computational setup, inspired by the experimental setup of Miura et al., Phys. Rev. E, 2006, is composed of a closed inviscid (one-dimensional) duct with adiabatic hard ends filled with CO2 at three supercritical pressures. The corresponding initial temperature values are taken along the pseudo-boiling line. Thermodynamic and transport properties of CO2 in near-critical conditions are modeled via the Peng-Robinson equation of state and Chung's Method. A heat source is applied at a distance from one end, with heat release intensities spanning the range 10^3-10^11 W/m^2, generating isentropic compression waves for values < 10^9 W/m^2. For higher heat-release rates such compressions are coalescent with distinct shock-like features (e.g. non-isentropicity and propagation Mach numbers measurably greater than unity) and a non-uniform post-shock state is present due to the strong thermodynamic nonlinearities. The resulting compression wave intensities have been collapsed via the thermal expansion coefficient, highly variable in near-critical fluids, used as one of the scaling parameters for the reference energy. The proposed scaling applies to isentropic thermoacoustic waves as well as shock waves up to shock strength 2. Long-term time integration reveals resonance behavior of the compression waves, raising the mean pressure and temperature at every resonance cycle. When the heat injection is halted, expansion waves are generated, which counteract the compression waves leaving conduction as the only thermal relaxation process. In the long term evolution, the decay in amplitude of the resonating waves observed in the experiments is qualitatively reproduced by using isothermal boundary conditions.
Resolving 3D Disk Orientation Using High-resolution Images: New Constraints on Circumgalactic Gas Inflows

Author(s): Ho, SH; Martin, CL | Abstract: We constrain gas inflow speeds in star-forming galaxies with color gradients consistent with inside-out disk growth. Our method combines new measurements of disk orientation with previously described circumgalactic absorption in background quasar spectra. Two quantities, a position angle and an axis ratio, describe the projected shape of each galactic disk on the sky, leaving an ambiguity about which side of the minor axis is tipped toward the observer. This degeneracy regarding the 3D orientation of disks has compromised previous efforts to measure gas inflow speeds. We present Hubble Space Telescope and Keck/LGSAO imaging that resolves the spiral structure in five galaxies at redshift z ≈ 0.2. We determine the sign of the disk inclination for four galaxies, under the assumption that spiral arms trail the rotation. We project models for both radial infall in the disk plane and circular orbits onto each quasar sightline. We compare the resulting line-of-sight velocities to the observed velocity range of Mg ii absorption in spectra of background quasars, which intersect the disk plane at radii between 69 and 115 kpc. For two sightlines, we constrain the maximum radial inflow speeds as 30-40 km s-1. We also rule out a velocity component from radial inflow in one sightline, suggesting that the structures feeding gas to these growing disks do not have unity covering factor. We recommend appropriate selection criteria for building larger samples of galaxy-quasar pairs that produce orientations sensitive to constraining inflow properties.
THE INTERMEDIATE LUMINOSITY OPTICAL TRANSIENT SN 2010DA: The PROGENITOR, ERUPTION, and AFTERMATH of A PECULIAR SUPERGIANT HIGH-MASS X-RAY BINARY

We present optical spectroscopy, ultraviolet-to-infrared imaging, and X-ray observations of the intermediate luminosity optical transient (ILOT) SN 2010da in NGC 300 (d = 1.86 Mpc) spanning from −6 to +6 years relative to the time of outburst in 2010. Based on the light-curve and multi-epoch spectral energy distributions of SN 2010da, we conclude that the progenitor of SN 2010da is a ≈10–12 M_⊙ yellow supergiant possibly transitioning into a blue-loop phase. During outburst, SN 2010da had a peak absolute magnitude of M_(bol) ≾ −10.4 mag, dimmer than other ILOTs and supernova impostors. We detect multi-component hydrogen Balmer, Paschen, and Ca ii emission lines in our high-resolution spectra, which indicate a dusty and complex circumstellar environment. Since the 2010 eruption, the star has brightened by a factor of ≈5 and remains highly variable in the optical. Furthermore, we detect SN 2010da in archival Swift and Chandra observations as an ultraluminous X-ray source (L_X ≈ 6 × 10^(39) erg s^(−1)). We additionally attribute He ii 4686 A and coronal Fe emission lines in addition to a steady X-ray luminosity of ≈10^(37) erg s^(−1) to the presence of a compact companion.
Spin-charge transformation of lattice fermion models : duality approach for diagrammatic simulation of strongly correlated systems

I derive a dual description of lattice fermions, specifically focusing on the t-J and Hubbard models, that allow diagrammatic techniques to be employed efficiently in the strongly correlated regime, as well as for systems with a restricted Hilbert space. These constructions are based on spin-charge transformation, where the lattice fermions of the original model are mapped onto spins and spin-less fermions. This mapping can then be combined with Popov-Fedotov fermionisation, where the spins are mapped onto lattice fermions with imaginary chemical potential. The resulting models do not contain any large expansion parameters, even for strongly correlated systems. Also, they exhibit dramatically smaller corrections to the density matrix from nonlinear terms in the Hamiltonian. The combination of these two properties means that they can be addressed with diagrammatic methods, including simulation techniques based on stochastic sampling of diagrammatic expansions.
Effects of Cowling Resistivity in the Weakly Ionized Chromosphere

The physics of the solar chromosphere is complex from both theoretical and modeling perspectives. The plasma temperature from the photosphere to corona increases from ~5,000 K to ~1 million K over a distance of only ~10,000 km from the chromosphere and the transition region. Certain regions of the solar atmosphere have sufficiently low temperature and ionization rates to be considered as weakly-ionized. In particular, this is true at the lower chromosphere. As a result, the Cowling resistivity is orders of magnitude greater than the Coulomb resistivity. Ohm's law therefore includes anisotropic dissipation. To evaluate the Cowling resistivity, we need to know the external magnetic field strength and to estimate the neutral fraction as a function of the bulk plasma density and temperature. In this study, we determine the magnetic field topology using the non-force-free field (NFFF) extrapolation technique based on SDO/HMI SHARP vector magnetogram data, and the stratified density and temperature profiles from the Maltby-M umbral core model for sunspots. We investigate the variation and effects of Cowling resistivity on heating and magnetic reconnection in the chromosphere as the flare-producing active region (AR) 11166 evolves. In particular, we analyze a C2.0 flare emerging from AR11166 and find a normalized reconnection rate of 0.051.
Prediction of highly cited papers

In an article in the pages of this journal five years ago, we described a method for predicting which scientific papers will be highly cited in the future, even if they are currently not highly cited. Applying the method to real citation data we made predictions about papers we believed would end up being well cited. Here we revisit those predictions, five years on, to see how well we did. Among the over 2000 papers in our original data set, we examine the fifty that, by the measures of our previous study, were predicted to do best and we find that they have indeed received substantially more citations in the intervening years than other papers, even after controlling for the number of prior citations. On average these top fifty papers have received 23 times as many citations in the last five years as the average paper in the data set as a whole, and 15 times as many as the average paper in a randomly drawn control group that started out with the same number of citations. Applying our prediction technique to current data, we also make new predictions of papers that we believe will be well cited in the next few years.
Multiple recurrence and convergence for certain averages along shifted primes

We show that any subset $A\subset \mathbb{N}$ with positive upper Banach density contains the pattern $\{m,m+[n{\it\alpha}],\dots ,m+k[n{\it\alpha}]\}$ , for some $m\in \mathbb{N}$ and $n=p-1$ for some prime $p$ , where ${\it\alpha}\in \mathbb{R}\setminus \mathbb{Q}$ . Making use of the Furstenberg correspondence principle, we do this by proving an associated recurrence result in ergodic theory along the shifted primes. We also prove the convergence result for the associated averages along primes and indicate other applications of these methods.
The Collapse of the Wien Tail in the Coldest Brown Dwarf? Hubble Space Telescope Near-Infrared Photometry of WISE J085510.83-071442.5

We present Hubble Space Telescope (HST) near-infrared photometry of the coldest known brown dwarf, WISE J085510.83−071442.5 (WISE 0855−0714). WISE 0855−0714 was observed with the Wide Field Camera 3 (WFC3) on board HST using the F105W, F125W, and F160W filters, which approximate the Y, J, and H near-infrared bands. WISE 0855−0714 is undetected at F105W with a corresponding 2σ magnitude limit of ~26.9. We marginally detect WISE 0855−0714 in the F125W images (S/N ~ 4), with a measured magnitude of 26.41 ± 0.27, more than a magnitude fainter than the J-band magnitude reported by Faherty et al. WISE J0855−0714 is clearly detected in the F160W band, with a magnitude of 23.86 ± 0.03, the first secure detection of WISE 0855−0714 in the near-infrared. Based on these data, we find that WISE 0855−0714 has extremely red F 105W - F125W and F125W - F160W colors relative to other known Y dwarfs. We find that when compared to the models of Saumon et al. and Morley et al., the F105W -F125W and F125W - F160W colors of WISE 0855−0714 cannot be accounted for simultaneously. These colors likely indicate that we are seeing the collapse of flux on the Wien tail for this extremely cold object.
PROPINQUITY OF CURRENT AND VORTEX STRUCTURES: EFFECTS ON COLLISIONLESS PLASMA HEATING

Intermittency of heating in weakly collisional plasma turbulence is an active subject of research, with significant potential impact on understanding of the solar wind, solar corona and astrophysical plasmas. Recent studies suggest a role of vorticity in plasma heating. In magnetohydrodynamics small scale vorticity is generated near current sheets and this effect persists in kinetic plasma, as demonstrated here with hybrid and fully kinetic Particle-In-Cell (PIC) simulations. Furthermore, vorticity enhances local kinetic effects, with a generalized resonance condition selecting sign-dependent enhancements or reductions of proton heating and thermal anisotropy. In such plasmas heating is correlated with vorticity and current density, but more strongly with vorticity. These results help explain several prior results that find kinetic effects and energization near to, but not centered on, current sheets. Evidently intermittency in kinetic plasma involves multiple physical quantities, and the associated coherent structures and nonthermal effects are closely related.
Entropy-Stable, High-Order Summation-by-Parts Discretizations Without Interface Penalties

The paper presents high-order accurate, energy-, and entropy-stable discretizations constructed from summation-by-parts (SBP) operators. Notably, the discretizations assemble global SBP operators and use continuous solutions, unlike previous efforts that use discontinuous SBP discretizations. Derivative-based dissipation and local-projection stabilization (LPS) are investigated as options for stabilizing the baseline discretization. These stabilizations are equal up to a multiplicative constant in one dimension, but only LPS remains well conditioned for general, multidimensional SBP operators. Furthermore, LPS is able to take advantage of the additional nodes required by degree 2p diagonal-norms, resulting in an element-local stabilization with a bounded spectral radius. An entropy-stable version of LPS is easily obtained by applying the projection on the entropy variables. Numerical experiments with the linear-advection and Euler equations demonstrate the accuracy, efficiency, and robustness of the stabilized discretizations, and the continuous approach compares favorably with the more common discontinuous SBP methods.
Intuitionistic Epistemic Logic

We outline an intuitionistic view of knowledge which maintains the original Brouwer–Heyting–Kolmogorov semantics for intuitionism and is consistent with the well-known approach that intuitionistic knowledge be regarded as the result of verification. We argue that on this view coreflection A → KA is valid and the factivity of knowledge holds in the form KA → ¬¬A ‘known propositions cannot be false’.We show that the traditional form of factivity KA → A is a distinctly classical principle which, like tertium non datur A ∨ ¬A, does not hold intuitionistically, but, along with the whole of classical epistemic logic, is intuitionistically valid in its double negation form ¬¬(KA ¬ A).Within the intuitionistic epistemic framework the knowability paradox is resolved in a constructive manner. We argue that this paradox is the result of an unwarranted classical reading of constructive principles and as such does not have the consequences for constructive foundations traditionally attributed it.
Hybrid metal-dielectric nanocavity for enhanced light-matter interactions

Despite tremendous advances in the fundamentals and applications of cavity quantum electrodynamics (CQED), investigations in this field have primarily been limited to optical cavities composed of purely dielectric materials. Here, we demonstrate a hybrid metal-dielectric nanocavity design and realize it in the InAs/GaAs quantum photonics platform utilizing angled rotational metal evaporation. Key features of our nanometallic light-matter interface include: (i) order of magnitude reduction in mode volume compared to that of leading photonic crystal CQED systems; (ii) surface-emitting nanoscale cylindrical geometry and therefore good collection efficiency; and finally (iii) strong and broadband spontaneous emission rate enhancement (Purcell factor ~ 8) of single photons. This light-matter interface may play an important role in quantum technologies.
Charge renormalization, effective interactions, and thermodynamics of deionized colloidal suspensions

Thermodynamic properties of charge-stabilized colloidal suspensions depend sensitively on the effective charge of the macroions, which can be substantially lower than the bare charge in the case of strong counterion–macroion association. A theory of charge renormalization is proposed, combining an effective one-component model of charged colloids with a thermal criterion for distinguishing between free and associated counterions. The theory predicts, with minimal computational effort, osmotic pressures of deionized suspensions of highly charged colloids in close agreement with large-scale simulations of the primitive model.
Quantum fluctuations and glassy behavior of electrons near metal-insulator transitions

Glassy behavior is a generic feature of electrons close to disorder-driven metal-insulator transitions. Deep in the insulating phase, electrons are tightly bound to impurities, and thus classical models for electron glasses have long been used. As the metallic phase is approached, quantum fluctuations become more important, as they control the electronic mobility. In this paper we review recent work that used extended dynamical mean-field approaches to discuss the influence of such quantum fluctuations on the glassy behavior of electrons, and examine how the stability of the glassy phase is affected by the Anderson and the Mott mechanisms of localization.
Adding fundamental matter to \Chiral rings and anomalies in supersymmetric gauge theory"

We consider a supersymmetric U(N) gauge theory with matter fields in the adjoint, fundamental and anti-fundamental representations. As in the framework which was put forward by Dijkgraaf and Vafa, this theory can be described by a matrix model. We analyze this theory along the lines of (F. Cachazo, M. Douglas, N.S. and E. Witten, ``Chiral Rings and Anomalies in Supersymmetric Gauge Theory'' [26]) and show the equivalence of the gauge theory and the matrix model. In particular, the anomaly equations in the gauge theory are identified with the loop equations in the matrix model.
New developments in calorimetric particle detection

Abstract In nuclear, particle and astroparticle physics experiments, calorimeters are used to measure the properties of particles with kinetic energies that range from a fraction of 1 eV to 1 0 20 eV or more. These properties are not necessarily limited to the energy carried by these particles, but may concern the entire four-vector, including the particle mass and type. In many modern experiments, large calorimeter systems play a central role, and this is expected to be no different for experiments that are currently being planned/designed for future accelerators. In this paper, the state of the art as well as new developments in calorimetry are reviewed. The latter are of course inspired by the perceived demands of future experiments, and/or the increasing demands of the current generation of experiments, as these are confronted with, for example, increased luminosity. These demands depend on the particles to be detected by the calorimeter. In electromagnetic calorimeters, radiation hardness of the detector components is a major concern. The generally poor performance of the current generation of hadron calorimeters is considered inadequate for future experiments, and a lot of the R&D in the past decade has focused on improving this performance. The root causes of the problems are investigated and different methods that have been exploited to remedy this situation are evaluated. In the past two decades, experiments in astroparticle physics have started to make major contributions to our fundamental understanding of physics and of a variety of processes that are inaccessible in laboratory experiments here on Earth. These experiments typically make use of calorimetric particle detection. At the extreme low end of the energy spectrum, ingenious instruments are used to study phenomena involving energy transfers of the order of 1 eV using calorimetric methods. In separate sections, some salient aspects of this work are reviewed.
Extended Formulations in Mixed-Integer Convex Programming

We present a unifying framework for generating extended formulations for the polyhedral outer approximations used in algorithms for mixed-integer convex programming MICP. Extended formulations lead to fewer iterations of outer approximation algorithms and generally faster solution times. First, we observe that all MICP instances from the MINLPLIB2 benchmark library are conic representable with standard symmetric and nonsymmetric cones. Conic reformulations are shown to be effective extended formulations themselves because they encode separability structure. For mixed-integer conic-representable problems, we provide the first outer approximation algorithm with finite-time convergence guarantees, opening a path for the use of conic solvers for continuous relaxations. We then connect the popular modeling framework of disciplined convex programming DCP to the existence of extended formulations independent of conic representability. We present evidence that our approach can yield significant gains in practice, with the solution of a number of open instances from the MINLPLIB2 benchmark library.
Bounding the outcome of a two-photon interference measurement using weak coherent states.

The interference of two photons at a beam splitter is at the core of many quantum photonic technologies, such as quantum key distribution or linear-optics quantum computing. Observing high-visibility interference is challenging because of the difficulty of realizing indistinguishable single-photon sources. Here, we perform a two-photon interference experiment using phase-randomized weak coherent states with different mean photon numbers. We place a tight upper bound on the expected coincidences for the case when the incident wavepackets contain single photons, allowing us to observe the Hong–Ou–Mandel effect. We find that the interference visibility is at least as large as 0.995−0.013+0.005.