cssi/SciSciGPT-SciSciNet huggingface dataset:
Hysteresis Effects in Social Behavior with Parasitic Infection

Recent work has found that the behavior of an individual can be altered when infected by a parasite. Here we explore the question: under what conditions, in principle, can a general parasitic infection control system-wide social behaviors? We analyze fixed points and hysteresis effects under the Master Equation, with transitions between two behaviors given two different subpopulations, healthy vs. parasitically-infected, within a population which is kept fixed overall. The key model choices are: (i) the internal opinion of infected humans may differ from that of the healthy population, (ii) the extent that interaction drives behavioral changes may also differ, and (iii) indirect interactions are most important. We find that the socioconfiguration can be controlled by the parasitically-infected population, under some conditions, even if the healthy population is the majority and of opposite opinion.
Real-time chiral dynamics from a digital quantum simulation

The chiral magnetic effect in a strong magnetic field can be described using the chiral anomaly in the (1+1)-dimensional massive Schwinger model with a time-dependent θ term. We perform a digital quantum simulation of the model at finite θ angle and vanishing gauge coupling using an IBM-Q digital quantum simulator, and observe the corresponding vector current induced in a system of relativistic fermions by a global chiral quench—a sudden change in the chiral chemical potential or θ angle. At finite fermion mass, there appears an additional contribution to this current that stems from the nonanomalous relaxation of chirality. Our results are relevant for the real-time dynamics of chiral magnetic effect in heavy ion collisions and in chiral materials, as well as for modeling high-energy processes at hadron colliders.
Optimized quantum photonics

Most quantum technologies rely on homogeneous, long lived qubits which are efficiently optically interconnected. To achieve this goal, we have been studying color centers in diamond and silicon carbide, in combination with novel fabrication techniques, and our photonics inverse design approach.
Formality Theorem for Hochschild Cochains via Transfer

We construct a 2-colored operad Ger∞ which, on the one hand, extends the operad Ger∞ governing homotopy Gerstenhaber algebras and, on the other hand, extends the 2-colored operad governing open-closed homotopy algebras. We show that Tamarkin’s Ger∞-structure on the Hochschild cochain complex C•(A, A) of an A∞-algebra A extends naturally to a \({{\bf Ger}^+_{\infty}}\)-structure on the pair (C•(A, A), A). We show that a formality quasi-isomorphism for the Hochschild cochains of the polynomial algebra can be obtained via transfer of this \({{\bf Ger}^+_{\infty}}\)-structure to the cohomology of the pair (C•(A, A), A). We show that \({{\bf Ger}^+_{\infty}}\) is a sub DG operad of the first sheet E1(SC) of the homology spectral sequence for the Fulton–MacPherson version SC of Voronov’s Swiss Cheese operad. Finally, we prove that the DG operads \({{\bf Ger}^+_{\infty}}\) and E1(SC) are non-formal.
Causality and information transfer in simultaneously slow- and fast-light media

We demonstrate the simultaneous propagation of slow- and fast-light optical pulses in a four-wave mixing scheme using warm potassium vapor. We show that when the system is tuned such that the input probe pulses exhibit slow-light group velocities and the generated pulses propagate with negative group velocities, the information velocity in the medium is nonetheless constrained to propagate at, or less than, c. These results demonstrate that the transfer and copying of information on optical pulses to those with negative group velocities obeys information causality, in a manner that is reminiscent of a classical version of the no-cloning theorem. Additionally, these results support the fundamental concept that points of non-analyticity on optical pulses correspond to carriers of new information.
OBSERVATIONS AND MAGNETIC FIELD MODELING OF A SOLAR POLAR CROWN PROMINENCE

We present observations and magnetic field modeling of the large polar crown prominence that erupted on 2010 December 6. Combination of Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and STEREO_Behind/EUVI allows us to see the fine structures of this prominence both at the limb and on the disk. We focus on the structures and dynamics of this prominence before the eruption. This prominence contains two parts: an active region part containing mainly horizontal threads and a quiet-Sun part containing mainly vertical threads. On the northern side of the prominence channel, both AIA and EUVI observe bright features which appear to be the lower legs of loops that go above then join in the filament. Filament materials are observed to frequently eject horizontally from the active region part to the quiet-Sun part. This ejection results in the formation of a dense-column structure (concentration of dark vertical threads) near the border between the active region and the quiet Sun. Using the flux rope insertion method, we create nonlinear force-free field models based on SDO/Helioseismic and Magnetic Imager line-of-sight magnetograms. A key feature of these models is that the flux rope has connections with the surroundings photosphere, so its axial flux varies along the filament path. The height and location of the dips of field lines in our models roughly replicate those of the observed prominence. Comparison between model and observations suggests that the bright features on the northern side of the channel are the lower legs of the field lines that turn into the flux rope. We suggest that plasma may be injected into the prominence along these field lines. Although the models fit the observations quiet well, there are also some interesting differences. For example, the models do not reproduce the observed vertical threads and cannot explain the formation of the dense-column structure.
Robust Pre-Training by Adversarial Contrastive Learning

Recent work has shown that, when integrated with adversarial training, self-supervised pre-training can lead to state-of-the-art robustness In this work, we improve robustness-aware self-supervised pre-training by learning representations that are consistent under both data augmentations and adversarial perturbations. Our approach leverages a recent contrastive learning framework, which learns representations by maximizing feature consistency under differently augmented views. This fits particularly well with the goal of adversarial robustness, as one cause of adversarial fragility is the lack of feature invariance, i.e., small input perturbations can result in undesirable large changes in features or even predicted labels. We explore various options to formulate the contrastive task, and demonstrate that by injecting adversarial perturbations, contrastive pre-training can lead to models that are both label-efficient and robust. We empirically evaluate the proposed Adversarial Contrastive Learning (ACL) and show it can consistently outperform existing methods. For example on the CIFAR-10 dataset, ACL outperforms the previous state-of-the-art unsupervised robust pre-training approach by 2.99% on robust accuracy and 2.14% on standard accuracy. We further demonstrate that ACL pre-training can improve semi-supervised adversarial training, even when only a few labeled examples are available. Our codes and pre-trained models have been released at: this https URL.
Hardware-accelerated SAR simulation with NVIDIA-RTX technology

Synthetic Aperture Radar (SAR) is a critical sensing technology that is notably independent of the sensorto- target distance and has numerous cross-cutting applications, e.g., target recognition, mapping, surveillance, oceanography, geology, forestry (biomass, deforestation), disaster monitoring (volcano eruptions, oil spills, ooding), and infrastructure tracking (urban growth, structure mapping). SAR uses a high-power antenna to illuminate target locations with electromagnetic radiation, e.g., 10GHz radio waves, and illuminated surface backscatter is sensed by the antenna which is then used to generate images of structures. Real SAR data is difficult and costly to produce and, for research, lacks a reliable source ground truth. Few SAR software simulators are available and even less are open source and can be validated. This article proposes a open source SAR simulator to compute phase histories for arbitrary 3D scenes using newly available ray-tracing hardware made available commercially through the NVIDIA's RTX graphics cards series. The OptiX GPU ray tracing library for NVIDIA GPUs is used to calculate SAR phase histories at unprecedented computational speeds. The simulation results are validated against existing SAR simulation code for spotlight SAR illumination of point targets. The computational performance of this approach provides orders of magnitude speed increases over CPU simulation. An additional order of magnitude of GPU acceleration when simulations are run on RTX GPUs which include hardware specifically to accelerate OptiX ray tracing. The article describes the OptiX simulator structure, processing framework and calculations that afford execution on massively parallel GPU computation device. The shortcoming of the OptiX library's restriction to single precision oat representation is discussed and modifications of sensitive calculations are proposed to reduce truncation error thereby increasing the simulation accuracy under this constraint.
The Future of Stellar Populations Studies in the Milky Way and the Local Group

The last decade has seen enormous progress in understanding the structure of the Milky Way and neighboring galaxies via the production of large-scale digital surveys of the sky like 2MASS and SDSS, as well as specialized, counterpart imaging surveys of other Local Group systems. Apart from providing snaphots of galaxy structure, these "cartographic" surveys lend insights into the formation and evolution of galaxies when supplemented with additional data (e.g., spectroscopy, astrometry) and when referenced to theoretical models and simulations of galaxy evolution. These increasingly sophisticated simulations are making ever more specific predictions about the detailed chemistry and dynamics of stellar populations in galaxies. To fully exploit, test and constrain these theoretical ventures demands similar commitments of observational effort as has been plied into the previous imaging surveys to fill out other dimensions of parameter space with statistically significant intensity. Fortunately the future of large-scale stellar population studies is bright with a number of grand projects on the horizon that collectively will contribute a breathtaking volume of information on individual stars in Local Group galaxies.
Cascade morphology transition in bcc metals

Energetic atom collisions in solids induce shockwaves with complex morphologies. In this paper, we establish the existence of a morphological transition in such cascades. The order parameter of the morphology is defined as the exponent, b, in the defect production curve as a function of cascade energy . Response of different bcc metals can be compared in a consistent energy domain when the energy is normalized by the transition energy, μ, between the high- and the low-energy regime. Using Cr, Fe, Mo and W data, an empirical formula of μ as a function of displacement threshold energy, Ed, is presented for bcc metals.
USING CROSS CORRELATIONS TO CALIBRATE LENSING SOURCE REDSHIFT DISTRIBUTIONS: IMPROVING COSMOLOGICAL CONSTRAINTS FROM UPCOMING WEAK LENSING SURVEYS

Cross correlations between the galaxy number density in a lensing source sample and that in an overlapping spectroscopic sample can in principle be used to calibrate the lensing source redshift distribution. In this paper, we study in detail to what extent this cross-correlation method can mitigate the loss of cosmological information in upcoming weak lensing surveys (combined with a cosmic microwave background prior) due to lack of knowledge of the source distribution. We consider a scenario where photometric redshifts are available and find that, unless the photometric redshift distribution p(z ph|z) is calibrated very accurately a priori (bias and scatter known to ~0.002 for, e.g., EUCLID), the additional constraint on p(z ph|z) from the cross-correlation technique to a large extent restores the cosmological information originally lost due to the uncertainty in dn/dz(z). Considering only the gain in photo-z accuracy and not the additional cosmological information, enhancements of the dark energy figure of merit of up to a factor of four (40) can be achieved for a SuMIRe-like (EUCLID-like) combination of lensing and redshift surveys, where SuMIRe stands for Subaru Measurement of Images and Redshifts). However, the success of the method is strongly sensitive to our knowledge of the galaxy bias evolution in the source sample and we find that a percent level bias prior is needed to optimize the gains from the cross-correlation method (i.e., to approach the cosmology constraints attainable if the bias was known exactly).
Excitonic effects on optical absorption spectra of doped graphene.

We have performed first-principles calculations to study optical absorption spectra of doped graphene with many-electron effects included. Both self-energy corrections and electron–hole interactions are reduced due to the enhanced screening in doped graphene. However, self-energy corrections and excitonic effects nearly cancel each other, making the prominent optical absorption peak fixed around 4.5 eV under different doping conditions. On the other hand, an unexpected increase of the optical absorbance is observed within the infrared and visible-light frequency regime (1–3 eV). Our analysis shows that a combining effect from the band filling and electron–hole interactions results in such an enhanced excitonic effect on the optical absorption. These unique variations of the optical absorption of doped graphene are of importance to understand relevant experiments and design optoelectronic applications.
Faster than classical quantum algorithm for dense formulas of exact satisfiability and occupation problems

We present an exact quantum algorithm for solving the Exact Satisfiability (XSAT) problem, which belongs to the important NP-complete complexity class. The algorithm is based on an intuitive approach that can be divided into two parts: First, the identification and efficient characterization of a restricted subspace that contains all the valid assignments of the XSAT; Second, a quantum search in such restricted subspace. The quantum algorithm can be used either to find a valid assignment (or to certify that no solution exists) or to count the total number of valid assignments. The query complexities for the worst-case are respectively bounded by $O(\sqrt{2^{n-M^{\prime}}})$ and $O(2^{n-M^{\prime}})$, where $n$ is the number of variables and $M^{\prime}$ the number of linearly independent clauses. Remarkably, the proposed quantum algorithm results to be faster than any known exact classical algorithm to solve dense formulas of XSAT. As a concrete application, we provide the worst-case complexity for the Hamiltonian cycle problem obtained after mapping it to a suitable XSAT. Specifically, we show that the time complexity for the proposed quantum algorithm is bounded by $O(2^{n/4})$ for 3-regular undirected graphs, where $n$ is the number of nodes. The same worst-case complexity holds for $(3,3)$-regular bipartite graphs (the current best classical algorithm has a (worst-case) running time bounded by $O(2^{31n/96})$). Finally, when compared to heuristic techniques for XSAT, the proposed quantum algorithm is faster than the classical WalkSAT and Adiabatic Quantum Optimization for random instances with a density of constraints close to the satisfiability threshold, the regime in which instances are typically the hardest to solve. The proposed quantum algorithm can be also extended to the generalized version of the XSAT known as Occupation problem.
Search Techniques for Distant Galaxies

How and when do galaxies form? Studies of the microwave background radiation reveal that the universe is spectacularly homogenous at redshift z ≈ 1000. Observations of the local universe reveal that by z = 0 much of the luminous matter has condensed into mature, gravitationally bound structures. One of the primary challenges to astronomers today is to achieve a robust understanding of this process of galaxy formation and evolution. Locating and studying young galaxies at large look-back times is an essential aspect of this program.We review the systematic observational techniques used to identify galaxies at early cosmic epochs. In the past few years, the study of normal, star-forming galaxies at z > 3 has become possible; indeed, successful methods have been developed to push the frontier past z = 5. We are now directly observing individual galaxies within a Gyr of the big bang. We present a detailed review of the many search methods used for identifying distant galaxies, consider the biases inherent in different search strategies, and discuss early results of these studies. We conclude with goals for future studies at the start of the 21st century.
DWARF GALAXY ANNIHILATION AND DECAY EMISSION PROFILES FOR DARK MATTER EXPERIMENTS

Gamma-ray searches for dark matter annihilation and decay in dwarf galaxies rely on an understanding of the dark matter density profiles of these systems. Conversely, uncertainties in these density profiles propagate into the derived particle physics limits as systematic errors. In this paper we quantify the expected dark matter signal from 20 Milky Way dwarfs using a uniform analysis of the most recent stellar-kinematic data available. Assuming that the observed stellar populations are equilibrium tracers of spherically symmetric gravitational potentials that are dominated by dark matter, we find that current stellar-kinematic data can predict the amplitudes of annihilation signals to within a factor of a few for the ultra-faint dwarfs of greatest interest. On the other hand, the expected signal from several classical dwarfs (with high-quality observations of large numbers of member stars) can be localized to the ~20% level. These results are important for designing maximally sensitive searches in current and future experiments using space and ground-based instruments.
CAUSTIC STRUCTURES AND DETECTABILITY OF CIRCUMBINARY PLANETS IN MICROLENSING

Recent discoveries of circumbinary planets in Kepler data show that there is a viable channel of planet formation around binary main sequence stars. Motivated by these discoveries, we have investigated the caustic structures and detectability of circumbinary planets in microlensing events. We have produced a suite of animations of caustics as a function of the projected separation and angle of the binary host to efficiently explore caustic structures over the entire circumbinary parameter space. Aided by these animations, we have derived a semi-empirical analytic expression for the location of planetary caustics, which are displaced in circumbinary lenses relative to those of planets with a single host. We have used this expression to show that the dominant source of caustic motion will be due to the planet's orbital motion and not that of the binary star. Finally, we estimate the fraction of circumbinary microlensing events that are recognizable as such to be significant (5-50 percent) for binary projected separations in the range 0.1-0.5 in units of Einstein radii.
Integrative analysis reveals disrupted pathways regulated by microRNAs in cancer

MicroRNAs (miRNAs) are small endogenous regulatory molecules that modulate gene expression post-transcriptionally. Although differential expression of miRNAs have been implicated in many diseases (including cancers), the underlying mechanisms of action remain unclear. Because each miRNA can target multiple genes, miRNAs may potentially have functional implications for the overall behavior of entire pathways. Here, we investigate the functional consequences of miRNA dysregulation through an integrative analysis of miRNA and mRNA expression data using a novel approach that incorporates pathway information a priori. By searching for miRNA-pathway associations that differ between healthy and tumor tissue, we identify specific relationships at the systems level which are disrupted in cancer. Our approach is motivated by the hypothesis that if an miRNA and pathway are associated, then the expression of the miRNA and the collective behavior of the genes in a pathway will be correlated. As such, we first obtain an expression-based summary of pathway activity using Isomap, a dimension reduction method which can articulate non-linear structure in high-dimensional data. We then search for miRNAs that exhibit differential correlations with the pathway summary between phenotypes as a means of finding aberrant miRNA-pathway coregulation in tumors. We apply our method to cancer data using gene and miRNA expression datasets from The Cancer Genome Atlas and compare ∼105 miRNA-pathway relationships between healthy and tumor samples from four tissues (breast, prostate, lung and liver). Many of the flagged pairs we identify have a biological basis for disruption in cancer.
Stability analysis of network of similar-plants via feedback network

In this paper, we study a networked control system with similar linear time-invariant plants. Using the master stability function method. We propose a network optimization method to minimize the feedback network order in the sense of the Frobenius norm. Then we verify our results with a numerical example. Additionally, we show that this method outperforms the known feedback network optimization methods namely matching condition.
The Swift? UVOT Stars Survey. III. Photometry and Color?Magnitude Diagrams of 103 Galactic Open Clusters

As part of the Swift/UVOT Stars Survey, we present near-ultraviolet point-source photometry for 103 Galactic open clusters. These data, taken over the span of the mission, provide a unique and unprecedented set of near-ultraviolet point-source photometry on simple stellar populations. After applying membership analysis fueled mostly by GAIA DR2 proper motions, we find that 49 of these 103 have clear precise CMDs amenable to investigation. We compare the CMDs to theoretical isochrones and find good agreement between the theoretical isochrones and the CMDs. The exceptions are the fainter parts of the main sequence and the red giant branch in the uvw2-uvw1 CMDs, which is most likely due either to the difficulty of correcting for the red leak in the uvw2 filter or limitations in our understanding of UV opacities for cool stars. For the most part, our derived cluster parameters -- age, distance and reddening -- agree with the consensus literature but we find a few clusters that warrant substantial revision from literature values, notably NGC~2304, NGC~2343, NGC~2360, NGC~2396, NGC~2428, NGC~2509, NGC~2533, NGC~2571, NGC~2818, Collinder~220 and NGC~6939. A number of clusters also show white dwarf and blue straggler sequences. We confirm the presence of extended main sequence turnoffs in NGC~2360 and NGC~2818 and show hints of it in a number of other clusters which may warrant future spectroscopic study. Most of the clusters in the study have low extinction and the rest are well fit by a "Milky-Way-like" extinction law. However, Collinder~220 hints at a possible "LMC-like" extinction law. We finally provide a comprehensive point-source catalog to the community as a tool for future investigation.
First-principles prediction of phononic thermal conductivity of silicene: A comparison with graphene

There has been great interest in two-dimensional materials, beyond graphene, for both fundamental sciences and technological applications. Silicene, a silicon counterpart of graphene, has been shown to possess some better electronic properties than graphene. However, its thermal transport properties have not been fully studied. In this paper, we apply the first-principles-based phonon Boltzmann transport equation to investigate the thermal conductivity of silicene as well as the phonon scattering mechanisms. Although both graphene and silicene are two-dimensional crystals with similar crystal structure, we find that phonon transport in silicene is quite different from that in graphene. The thermal conductivity of silicene shows a logarithmic increase with respect to the sample size due to the small scattering rates of acoustic in-plane phonon modes, while that of graphene is finite. Detailed analysis of phonon scattering channels shows that the linear dispersion of the acoustic out-of-plane (ZA) phonon modes, which is induced by the buckled structure, makes the long-wavelength longitudinal acoustic phonon modes in silicene not as efficiently scattered as that in graphene. Compared with graphene, where most of the heat is carried by the acoustic out-of-plane (ZA) phonon modes, the ZA phonon modes in silicene only have ∼10% contribution to the total thermal conductivity, which can also be attributed to the buckled structure. This systematic comparison of phonon transport and thermal conductivity of silicene and graphene using the first-principle-based calculations shed some light on other two-dimensional materials, such as two-dimensional transition metal dichalcogenides.
Non-Gaussian and Gottesman–Kitaev–Preskill state preparation by photon catalysis

Continuous-variable quantum-computing (CVQC) is the most scalable implementation of QC to date but requires non-Gaussian resources to allow exponential speedup and quantum correction, using error encoding such as Gottesman-Kitaev-Preskill (GKP) states. However, GKP state generation is still an experimental challenge. We show theoretically that photon catalysis, the interference of coherent states with single-photon states followed by photon-number-resolved detection, is a powerful enabler for non-Gaussian quantum state engineering such as exactly displaced single-photon states and $M$-symmetric superpositions of squeezed vacuum (SSV), including squeezed cat states ($M=2$). By including photon-counting based state breeding, we demonstrate the potential to enlarge SSV states and produce GKP states.
Anisotropic Boundary Layer Adaptivity of Multi-Element Wings

Multi-element wings are popular in the aerospace community due to their high lift performance. Turbulent flow simulations of these configurations require very fine mesh spacings especially near the walls, thereby making use of a boundary layer mesh necessary. However, it is difficult to accurately determine the required mesh resolution a priori to the simulations. In this paper we use an anisotropic adaptive meshing approach including adaptive control of elements in the boundary layers and study its effectiveness for two multielement wing configurations. The results are compared with experimental data as well as nested refinements to show the efficiency of adaptivity driven by error indicators, where superior resolution in wakes and near the tip region through adaptivity are highlighted.
EVIDENCE FOR A MASSIVE, EXTENDED CIRCUMGALACTIC MEDIUM AROUND THE ANDROMEDA GALAXY*

We demonstrate the presence of an extended and massive circumgalactic medium (CGM) around Messier 31 using archival HST Cosmic Origins Spectrograph ultraviolet spectroscopy of 18 QSOs projected within two virial radii of M31 ( kpc). We detect absorption from Si iii at km s−1 toward all three sightlines at , 3 of 4 sightlines at , and possibly 1 of 11 at . We present several arguments that the gas at these velocities observed in these directions originates from the M31 CGM rather than the Local Group or Milky Way CGM or Magellanic Stream. We show that the dwarf galaxies located in the CGM of M31 have very similar velocities over similar projected distances from M31. We find a non-trivial relationship only at these velocities between the column densities (N) of all the ions and R, whereby N decreases with increasing R. At , the covering fraction is close to unity for Si iii and C iv (–97% at the 90% confidence level), but drops to –20% at . We show that the M31 CGM gas is bound, multiphase, predominantly ionized, and is more highly ionized gas at larger R. We estimate using Si ii, Si iii, and Si iv, a CGM metal mass of M and gas mass of M within , and possibly a factor of ∼10 larger within , implying substantial metal and gas masses in the CGM of M31.
A Tangle of Stellar Streams in the North Galactic Cap

Stellar halo substructures were identified using statistical photometric parallax of blue main sequence turnoff stars from fourteen Sloan Digital Sky Survey stripes in the north Galactic cap. Four structures are consistent with previous measurements of the Sagittarius dwarf tidal stream: the leading tail, the "bifurcated" stream, the trailing tail, and Stream C. The stellar overdensity in Virgo, about 15 kpc from the Sun, could arise from the crossing of the Parallel Stream and a new, candidate stream dubbed the Perpendicular Stream. The data suggests the presence of a wide stream near NGC 5466, with a distance of 5 to 15 kpc. Measurements of the flattening of the smooth stellar halo from the fourteen stripes average q=0.58, with a dispersion of 0.04.
Turning the nuclear energy density functional method into a proper effective field theory: reflections

Nuclear energy density functionals (EDFs) have a long history of success in reproducing properties of nuclei across the table of the nuclides. They capture quantitatively the emergent features of bound nuclei, such as nuclear saturation and pairing, yet greater accuracy and improved uncertainty quantification are actively sought. Implementations of phenomenological EDFs are suggestive of effective field-theory (EFT) formulations and there are hints of an underlying power counting. Multiple paths are possible in trying to turn the nuclear EDF method into a proper EFT. I comment on the current situation and speculate on how to proceed using an effective action formulation.
How electrons spin

There are a number of reasons to think that the electron cannot truly be spinning. Given how small the electron is generally taken to be, it would have to rotate superluminally to have the right angular momentum and magnetic moment. Also, the electron's gyromagnetic ratio is twice the value one would expect for an ordinary classical rotating charged body. These obstacles can be overcome by examining the flow of mass and charge in the Dirac field (interpreted as giving the classical state of the electron). Superluminal velocities are avoided because the electron's mass and charge are spread over sufficiently large distances that neither the velocity of mass flow nor the velocity of charge flow need to exceed the speed of light. The electron's gyromagnetic ratio is twice the expected value because its charge rotates twice as fast as its mass.
Eigenvalue resolution of self-adjoint matrices

Resolution of a compact group action in the sense described by Albin and Melrose is applied to the conjugation action by the unitary group on self-adjoint matrices. It is shown that the eigenvalues are smooth on the resolved space and that the trivial bundle smoothly decomposes into the direct sum of global one-dimensional eigenspaces.
RESONANT SCATTERING OF EMISSION LINES IN CORONAL LOOPS: EFFECTS ON IMAGE MORPHOLOGY AND LINE RATIOS

We have investigated the effects of resonant scattering of emission lines on the image morphology and intensity from coronal loop structures. It has previously been shown that line-of-sight effects in optically thin line emission can yield loop images that appear uniformly bright at one viewing angle but show "looptop sources" at other viewing angles. For optically thick loops where multiple resonant scattering is important, we use a three-dimensional Monte Carlo radiation transfer code. Our simulations show that the intensity variation across the image is more uniform than the optically thin simulation, and depending on viewing angle the intensity may be lower or higher than that predicted from optically thin simulations due to scattering out of or into the line of sight.
Cosmological law of universal gravitation

Without exceeding the limits of the conventional ΛCDM paradigm, we argue for Yukawa law of interparticle interaction as the law of gravitation in the real expanding inhomogeneous universe. It covers the whole space and comes up to take place of Newtonian gravity, which is restricted exclusively to sub-horizon distances. The large-scale screening of gravitational interaction between every two nonrelativistic massive particles is ensured by the homogeneous cosmological background (specifically, by the nonzero average rest mass density of nonrelativistic matter). We take advantage of the uniform matter distribution case (i.e. the homogeneous universe limit) to demonstrate superiority of Yukawa gravity. Attention is also devoted to the concrete particular case of inhomogeneity.
Planetary Signatures in the SAO 206462 (HD 135344B) Disk: A Spiral Arm Passing through Vortex?

The disk surrounding SAO 206462, an 8 Myr old Herbig Ae star, has recently been reported to exhibit spiral arms, an asymmetric dust continuum, and a dust-depleted inner cavity. By carrying out two-dimensional, two-fluid hydrodynamic calculations, we find that a planetary-mass companion located at the outer disk could be responsible for these observed structures. In this model, the planet excites primary and secondary arms interior to its orbit. It also carves a gap and generates a local pressure bump at the inner gap edge where a vortex forms through Rossby wave instability. The vortex traps radially drifting dust particles, forming a dust-depleted cavity in the inner disk. We propose that the vortex is responsible for the brightest southwestern peak seen in infrared scattered light and sub-millimeter dust continuum emission. In particular, it is possible that the scattered light is boosted as one of the spiral arms passes through the high density vortex region, although the vortex alone may be able to explain the peak. We suggest that a planetary companion with a mass of 10–15 is orbiting SAO 206462 at 100–120 au. Monitoring of the brightest peak over the next few years will help reveal its origin because the spiral arms and vortex will show distinguishable displacement.
RELATIVISTIC SIMULATIONS OF BLACK HOLE–NEUTRON STAR COALESCENCE: THE JET EMERGES

We perform magnetohydrodynamic simulations in full general relativity (GRMHD) of a binary black hole–neutron star (BHNS) on a quasicircular orbit that undergoes merger. The binary mass ratio is 3:1, the black hole initial spin parameter (m is the black hole Christodoulou mass) aligned with the orbital angular momentum, and the neutron star is an irrotational polytrope. About two orbits prior to merger (at time ), we seed the neutron star with a dynamically weak interior dipole magnetic field that extends into the stellar exterior. At , the exterior has a low-density atmosphere with a constant plasma parameter . Varying β at tB in the exterior from 0.1 to 0.01, we find that at a time (M is the total (ADM) mass) following the onset of accretion of tidally disrupted debris, magnetic winding above the remnant black hole poles builds up the magnetic field sufficiently to launch a mildly relativistic, collimated outflow—an incipient jet. The duration of the accretion and the lifetime of the jet is s. Our simulations furnish the first explicit examples in GRMHD that show that a jet can emerge following a BHNS merger.
Information Theoretic Regret Bounds for Online Nonlinear Control.

This work studies the problem of sequential control in an unknown, nonlinear dynamical system, where we model the underlying system dynamics as an unknown function in a known Reproducing Kernel Hilbert Space. This framework yields a general setting that permits discrete and continuous control inputs as well as non-smooth, non-differentiable dynamics. Our main result, the Lower Confidence-based Continuous Control (LC3) algorithm, enjoys a near-optimal O(\sqrt{T}) regret bound against the optimal controller in episodic settings, where T is the number of episodes. The bound has no explicit dependence on dimension of the system dynamics, which could be infinite, but instead only depends on information theoretic quantities. We empirically show its application to a number of nonlinear control tasks and demonstrate the benefit of exploration for learning model dynamics.
An Old Cluster in NGC 6822

We present spectroscopy of two clusters in the dwarf irregular galaxy NGC 6822. From these we deduce an age for cluster VII of 11 Gyr and [Fe/H] = -1.95 ± 0.15 dex. Cluster VII appears to be an analog of the metal-poor Galactic globular clusters. Cluster VI is found to be much younger and more metal-rich, with an age of approximately 2 Gyr. Its derived metallicity, [Fe/H] ≈ -1.0 dex, is comparable to that of the gas seen today in NGC 6822. The existence of a metal-poor old cluster in NGC 6822 rules out models for the chemical evolution of this galaxy with significant prompt initial enhancement. We find that a star formation rate that is constant with time and is within a factor of 2 of the present star formation rate can reproduce the two points on the age-metallicity relationship for NGC 6822 over the past 10 Gyr defined by these two clusters.
Lack of Inflated Radii for Kepler Giant Planet Candidates Receiving Modest Stellar Irradiation

The most irradiated transiting hot Jupiters are characterized by anomalously inflated radii, sometimes exceeding Jupiter's size by more than 60%. While different theoretical explanations have been applied, none of them provide a universal resolution to this observation, despite significant progress in the past years. We refine the photometric transit light curve analysis of 115 Kepler giant planet candidates based on public Q0-Q2 photometry. We find that 14% of them are likely false positives, based on their secondary eclipse depth. We report on planet radii versus stellar flux. We find an increase in planet radii with increased stellar irradiation for the Kepler giant planet candidates, in good agreement with existing hot Jupiter systems. We find that in the case of modest irradiation received from the stellar host, giant planets do not have inflated radii, and appear to have radii independent of the host star incident flux. This finding suggests that the physical mechanisms inflating hot Jupiters become ineffective below a given orbit-averaged stellar irradiation level of ~2 × 108 erg s–1 cm–2.
Theoretically exact photoacoustic reconstruction from spatially and temporally reduced data

We investigate the inverse source problem for the wave equation, arising in photo- and thermoacoustic tomography. There exist quite a few theoretically exact inversion formulas explicitly expressing solution of this problem in terms of the measured data, under the assumption of constant and known speed of sound. However, almost all of these formulas require data to be measured either on an unbounded surface, or on a closed surface completely surrounding the object. This is too restrictive for practical applications. The alternative approach we present, under certain restriction on geometry, yields theoretically exact reconstruction of the standard Radon projections of the source from the data measured on a finite open surface. In addition, this technique reduces the time interval where the data should be known. In general, our method requires a pre-computation of densities of certain single-layer potentials. However, in the case of a truncated circular or spherical acquisition surface, these densities are easily obtained analytically, which leads to fully explicit asymptotically fast algorithms. We test these algorithms in a series of numerical simulations.
Low-Barrier Nanomagnets as p-Bits for Spin Logic

It has recently been shown that a suitably interconnected network of tunable telegraphic noise generators or “p-bits” can be used to perform even precise arithmetic functions like a 32-bit adder. In this letter, we use simulations based on the stochastic Landau–Lifshitz–Gilbert (sLLG) equation to demonstrate that similar impressive functions can be performed using unstable nanomagnets with energy barriers as low as a fraction of a kT. This is surprising because the magnetization of low-barrier nanomagnets is not telegraphic with discrete values of $\pm 1$ . Rather, it fluctuates randomly among all values between $-$ 1 and +1, and the output magnets are read with a thresholding device that translates all positive values to one and all negative values to zero. We present sLLG-based simulations demonstrating the operation of a 32-bit adder, with a network of several hundred nanomagnets, exhibiting a remarkably precise correlation: The input magnets { A } and { B } as well as the output magnets { S } all fluctuate randomly and yet the quantity $A+B$ $-$ $S$ is sharply peaked around zero! If we fix { A } and { B }, the sum magnets { S } rapidly converge to a unique state with $S=A+B$ so that the system acts as an adder. But unlike standard adders, the operation is invertible. If we fix { S } and { B }, the remaining magnets { A } converge to the difference $A=S-B$ . These examples emphasize a new direction for the field of nanomagnetics away from stable high-barrier magnets toward stochastic low-barrier magnets that not only operate with lower currents, but are also more promising for continued downscaling.
REDUNDANCIES IN EXPLICITLY CONSTRUCTED TEN-DIMENSIONAL HETEROTIC STRING MODELS

Using Baylor University's C++ software for construction of weakly coupled free fermionic heterotic string models, called the FF Framework, we explicitly construct the level-1 Kac–Moody ten-dimensional heterotic string models with the aim of understanding the redundancies endemic to this construction method. We show that for models in any even number of large space–time dimensions with a massless left-mover and an odd ordered right-mover, the maximal number of space–time supersymmetries are present. We show that in order to produce all of the models for a given order, different basis vectors must be built; one cannot vary only the GSO coefficients. We also show that all combinations of two order-2 basis vectors do not produce the same models as all possible single order-4 basis vectors, implying the product of the orders used in a search does not necessarily determine the models built. We also show that to build all of the D = 10 level-1 models the inputs must be: sets of single order-6 basis vectors, pairs of basis vectors with orders 3 and 2, or sets of three order-2 basis vectors.
Stabilizing inverse problems by internal data

Several newly developing hybrid imaging methods (e.g., those combining electrical impedance or optical imaging with acoustics) enable one to obtain some auxiliary interior information (usually some combination of the electrical conductivity and the current) about the parameters of the tissues. This information, in turn, happens to stabilize the exponentially unstable and thus low-resolution optical and electrical impedance tomography. Various known instances of this effect have been studied individually. We show that there is a simple general technique (covering all known cases) that shows what kinds of interior data stabilize the reconstruction, and why. Namely, we show when the linearized problem becomes an elliptic pseudo-differential one, and thus stable. Stability here is meant as the problem being Fredholm, so the local uniqueness is not shown and probably does not hold in such generality.
Non-diagonal open spin-1/2 XXZ quantum chains by separation of variables: complete spectrum and matrix elements of some quasi-local operators

The integrable quantum models, associated with the transfer matrices of the 6-vertex reflection algebra for spin-1/2 representations, are studied in this paper. In the framework of Sklyanin’s quantum separation of variables (SOV), we provide the complete characterization of the eigenvalues and eigenstates of the transfer matrix and the proof of the simplicity of the transfer matrix spectrum. Moreover, we use these integrable quantum models as further key examples for which to develop a method in the SOV framework to compute matrix elements of local operators. This method is based on the resolution of the quantum inverse problem (i.e. the reconstruction of local operators in terms of the quantum separate variables) plus the computation of the action of separate covectors on separate vectors. In particular, for these integrable quantum models, which in the homogeneous limit reproduce the open spin-1/2 XXZ quantum chains with non-diagonal boundary conditions, we have obtained the SOV-reconstruction for a class of quasi-local operators and determinant formulae for the covector–vector actions. As a consequence of these findings we provide one determinant formula for the matrix elements of this class of reconstructed quasi-local operator on transfer matrix eigenstates.
Massive and massless spin-2 scattering and asymptotic superluminality

We constrain theories of a massive spin-2 particle coupled to a massless spin-2 particle by demanding the absence of a time advance in eikonal scattering. This is an S-matrix consideration that leads to model-independent constraints on the cubic vertices present in the theory. Of the possible cubic vertices for the two spin-2 particles, the requirement of subluminality leaves a particular linear combination of cubic vertices of the Einstein-Hilbert type. Either the cubic vertices must appear in this combination or new physics must enter at a scale parametrically the same as the mass of the massive spin-2 field, modulo some standard caveats. These conclusions imply that there is a one-parameter family of ghost-free bimetric theories of gravity that are consistent with subluminal scattering. When both particles couple to additional matter, subluminality places additional constraints on the matter couplings. We additionally reproduce these constraints by considering classical scattering off of a shockwave background in the ghost-free bimetric theory.
Compression in the Space of Permutations

We investigate lossy compression (source coding) of data in the form of permutations. This problem has direct applications in the storage of ordinal data or rankings, and in the analysis of sorting algorithms. We analyze the rate-distortion characteristic for the permutation space under the uniform distribution, and the minimum achievable rate of compression that allows a bounded distortion after recovery. Our analysis is with respect to different practical and useful distortion measures, including Kendall tau distance, Spearman’s footrule, Chebyshev distance, and inversion- $\ell _{1}$ distance. We establish equivalence of source code designs under certain distortions and show simple explicit code designs that incur low encoding/decoding complexities and are asymptotically optimal. Finally, we show that for the Mallows model, a popular nonuniform ranking model on the permutation space, both the entropy and the maximum distortion at zero rate are much lower than the uniform counterparts, which motivates the future design of efficient compression schemes for this model.