cssi/SciSciGPT-SciSciNet huggingface dataset:
Spatial Evidence for Transition Radiation in a Solar Radio Burst

Microturbulence, i.e., enhanced fluctuations of plasma density and electric and magnetic fields, is of great interest in astrophysical plasmas, but occurs on spatial scales far too small to resolve by remote sensing, e.g., at ~1-100 cm in the solar corona. This Letter reports spatially resolved observations that offer strong support for the presence in solar flares of a suspected radio emission mechanism, resonant transition radiation, which is tightly coupled to the level of microturbulence and provides direct diagnostics of the existence and level of fluctuations on decimeter spatial scales. Although the level of the microturbulence derived from the radio data is not particularly high, Δn2/n2 ~ 10-5, it is large enough to affect the charged particle diffusion and give rise to effective stochastic acceleration. This finding has exceptionally broad astrophysical implications, since modern sophisticated numerical models predict generation of much stronger turbulence in relativistic objects, e.g., in gamma-ray burst sources.
Supersymmetry on a Spatial Lattice

We construct a variety of supersymmetric gauge theories on a spatial lattice, including N = 4 supersymmetric Yang-Mills theory in 3+1 dimensions. Exact lattice supersymmetry greatly reduces or eliminates the need for fine tuning to arrive at the desired continuum limit in these examples.
D-brane scattering and annihilation

We study the dynamics of parallel brane-brane and brane-antibrane scattering in string theory in flat spacetime, focusing on the pair production of open strings that stretch between the branes. We are particularly interested in the case of scattering at small impact parameter b < l s , where there is a tachyon in the spectrum when a brane and an antibrane approach within a string length. Our conclusion is that despite the tachyon, branes and antibranes can pass through each other with only a very small probability of annihilating, so long as g s is small and the relative velocity v is neither too small nor too close to 1. Our analysis is relevant also to the case of charged open string production in world-volume electric fields, and we make use of this T-dual scenario in our analysis. We briefly discuss the application of our results to a stringy model of inflation involving moving branes.
Entanglement at a Scale and Renormalization Monotones

We study the information content of the reduced density matrix of a region in quantum field theory that cannot be recovered from its subregion density matrices. We reconstruct the density matrix from its subregions using two approaches: scaling maps and recovery maps. The vacuum of a scale-invariant field theory is the fixed point of both transformations. We define the entanglement of scaling and the entanglement of recovery as measures of entanglement that are intrinsic to the continuum limit. Both measures increase monotonically under the renormalization group flow. This provides a unifying information-theoretic structure underlying the different approaches to the renormalization monotones in various dimensions. Our analysis applies to non-relativistic quantum field theories as well the relativistic ones, however, in relativistic case, the entanglement of scaling can diverge.
Ultraviolet limit of open string theory

We confirm the intuition that a string theory which is perturbatively infrared finite is automatically perturbatively ultraviolet finite. Our derivation based on the asymptotics of the Selberg trace formula for the Greens function on a riemannian surface holds for both open and closed string amplitudes and is independent of modular invariance and supersymmetry. The masses of the open strings stretched between D-branes give a natural world-sheet ultraviolet regulator for the string path integral preserving both T-duality and open-closed string world-sheet duality.
Linearity of Holographic Entanglement Entropy

We consider the question of whether the leading contribution to the entanglement entropy in holographic CFTs is truly given by the expectation value of a linear operator as is suggested by the Ryu-Takayanagi formula. We investigate this property by computing the entanglement entropy, via the replica trick, in states dual to superpositions of macroscopically distinct geometries and find it consistent with evaluating the expectation value of the area operator within such states. However, we find that this fails once the number of semi-classical states in the superposition grows exponentially in the central charge of the CFT. Moreover, in certain such scenarios we find that the choice of surface on which to evaluate the area operator depends on the density matrix of the entire CFT. This nonlinearity is enforced in the bulk via the homology prescription of Ryu-Takayanagi. We thus conclude that the homology constraint is not a linear property in the CFT. We also discuss the existence of ‘entropy operators’ in general systems with a large number of degrees of freedom.
The pitfalls of planar spin-glass benchmarks: raising the bar for quantum annealers (again)

In an effort to overcome the limitations of random spin-glass benchmarks for quantum annealers, focus has shifted to carefully crafted gadget-based problems whose logical structure typically has a planar topology. Recent experiments on these gadget problems using a commercially available quantum annealer have demonstrated an impressive performance over a selection of commonly used classical optimisation heuristics. Here, we show that efficient classical optimisation techniques, such as minimum-weight-perfect matching, can solve these gadget problems exactly and in polynomial time. We present approaches on how to mitigate this shortcoming of commonly used benchmark problems based on planar logical topologies.
Clausius' entropy revisited

Conventional nonequilibrium thermodynamics is mainly concerned with systems in local equilibrium and their entropy production, due to the irreversible processes which take place in these systems. In this paper, fluids will be considered in a state of local equilibrium. We argue that the main feature of such systems is not the entropy production, but the organization of the flowing currents in such systems. These currents do not only have entropy production, but must also have an organization needed to flow in a certain direction. It is the latter, which is the source of the equilibrium entropy, when the fluid goes from a local equilibrium state to an equilibrium state. This implies a transmutation of the local equilibrium currents' organization into the equilibrium entropy. Alternatively, when a fluid goes from an equilibrium state to a local equilibrium state, its entropy transmutes into the organization of the currents of that state.
DIRECT EVALUATION OF THE HELIUM ABUNDANCES IN OMEGA CENTAURI

A direct measure of the helium abundances from the near-infrared transition of He I at 1.08 μm is obtained for two nearly identical red giant stars in the globular cluster Omega Centauri. One star exhibits the He I line; the line is weak or absent in the other star. Detailed non-local thermal equilibrium semi-empirical models including expansion in spherical geometry are developed to match the chromospheric Hα, Hβ, and Ca II K lines, in order to predict the helium profile and derive a helium abundance. The red giant spectra suggest a helium abundance of Y ≤ 0.22 (LEID 54064) and Y = 0.39-0.44 (LEID 54084) corresponding to a difference in the abundance ΔY ≥ 0.17. Helium is enhanced in the giant star (LEID 54084) that also contains enhanced aluminum and magnesium. This direct evaluation of the helium abundances gives observational support to the theoretical conjecture that multiple populations harbor enhanced helium in addition to light elements that are products of high-temperature hydrogen burning. We demonstrate that the 1.08 μm He I line can yield a helium abundance in cool stars when constraints on the semi-empirical chromospheric model are provided by other spectroscopic features.
Stochastic Differential Equation Model for Spontaneous Emission and Carrier Noise in Semiconductor Lasers

We present a new stochastic differential equation model for the spontaneous emission noise and carrier noise in semiconductor lasers. The correlations between these two types of noise have often been neglected in recent studies of the effects of the noise on the laser dynamics. However, the classic results of Henry show that the intensity noise and the carrier noise are strongly negatively correlated. Our model demonstrates how to properly account for these correlations since the corresponding diffusion coefficients agree exactly with those derived by Henry. We show that in fact in the correct model the spontaneous emission noise and the carrier noise are driven by the same Wiener processes. Furthermore, we demonstrate that the nonzero correlation time of the physical noise affects the mean dynamics of both the electric field amplitude and the carrier number. We show that these are systematic corrections that can be described by additional drift terms in the model.
CFT unitarity and the AdS Cutkosky rules

We derive the Cutkosky rules for conformal field theories (CFTs) at weak and strong coupling. These rules give a simple, diagrammatic method to compute the double-commutator that appears in the Lorentzian inversion formula. We first revisit weakly-coupled CFTs in flat space, where the cuts are performed on Feynman diagrams. We then generalize these rules to strongly-coupled holographic CFTs, where the cuts are performed on the Witten diagrams of the dual theory. In both cases, Cutkosky rules factorize loop diagrams into on-shell sub-diagrams and generalize the standard S-matrix cutting rules. These rules are naturally formulated and derived in Lorentzian momentum space, where the double-commutator is manifestly related to the CFT optical theorem. Finally, we study the AdS cutting rules in explicit examples at tree level and one loop. In these examples, we confirm that the rules are consistent with the OPE limit and that we recover the S-matrix optical theorem in the flat space limit. The AdS cutting rules and the CFT dispersion formula together form a holographic unitarity method to reconstruct Witten diagrams from their cuts.
Constructing Energy-efficient Mixed-precision Neural Networks through Principal Component Analysis for Edge Intelligence

The ‘Internet of Things’ has brought increased demand for artificial intelligence-based edge computing in applications ranging from healthcare monitoring systems to autonomous vehicles. Quantization is a powerful tool to address the growing computational cost of such applications and yields significant compression over full-precision networks. However, quantization can result in substantial loss of performance for complex image classification tasks. To address this, we propose a principal component analysis (PCA)-driven methodology to identify the important layers of a binary network, and design mixed-precision networks. The proposed Hybrid-Net achieves a more than 10% improvement in classification accuracy over binary networks such as XNOR-Net for ResNet and VGG architectures on CIFAR-100 and ImageNet datasets, while still achieving up to 94% of the energy efficiency of XNOR-Nets. This work advances the feasibility of using highly compressed neural networks for energy-efficient neural computing in edge devices. Neural networks are often implemented with reduced precision in order to meet the tight energy and memory budget required by edge computing devices. Chakraborty et al. develop a technique for assessing which layers can be quantized, and by how much, without sacrificing too much on performance.
Plasmoid instability in the semi-collisional regime

We investigate analytically and numerically the semi-collisional regime of the plasmoid instability, defined by the inequality . The simulations do not prescribe a Sweet–Parker sheet; rather, one is formed self-consistently during the nonlinear evolution of the initial tearing mode configuration. This proves that this regime of the plasmoid instability is realizable, at least at the relatively low values of the Lundquist number that are accessible to current dedicated experiments.
STUDIES OF THE DIFFUSE INTERSTELLAR BANDS. III. HD 183143

Echelle spectra of HD 183143 [B7Iae, E(B − V) = 1.27] were obtained on three nights, at a resolving power R = 38,000 and with a signal-to-noise ratio ≈ 1000 at 6400 A in the final, combined spectrum. A catalog is presented of 414 diffuse interstellar bands (DIBs) measured between 3900 and 8100 A in this spectrum. The central wavelengths, the widths (FWHM), and the equivalent widths of nearly all of the bands are tabulated, along with the minimum uncertainties in the latter. Among the 414 bands, 135 (or 33%) were not reported in four previous, modern surveys of the DIBs in the spectra of various stars, including HD 183143. The principal result of this study is that the great majority of the bands in the catalog are very weak and fairly narrow. Typical equivalent widths amount to a few mA, and the bandwidths (FWHM) are most often near 0.7 A. No preferred wavenumber spacings among the 414 bands are identified which could provide clues to the identities of the large molecules thought to cause the DIBs. At generally comparable detection limits in both spectra, the population of DIBs observed toward HD 183143 is systematically redder, broader, and stronger than that seen toward HD 204827 (Paper II). In addition, interstellar lines of C2 molecules have not been detected toward HD 183143, while a very high value of N(C2)/E(B − V )i s observed toward HD 204827. Therefore, either the abundances of the large molecules presumed to give rise to the DIBs, or the physical conditions in the absorbing clouds, or both, must differ significantly between the two cases.
Bright Ultraviolet Regions and Star Formation Characteristics in Nearby Dwarf Galaxies

We compare star formation in the inner and outer disks of 11 dwarf irregular galaxies (dIm) within 3.6 Mpc. The regions are identified on Galaxy Evolution Explorer near-UV images, and modeled with UV, optical, and near-IR colors to determine masses and ages. A few galaxies have made 10{sup 5}-10{sup 6} M {sub sun} complexes in a starburst phase, while others have not formed clusters in the last 50 Myr. The maximum region mass correlates with the number of regions as expected from the size-of-sample effect. We find no radial gradients in region masses and ages, even beyond the realm of H{alpha} emission, although there is an exponential decrease in the luminosity density and number density of the regions with radius. H{alpha} is apparently lacking in the outer parts only because nebular emission around massive stars is too faint to see. The outermost regions for the five galaxies with H I data formed at average gas surface densities of 1.9-5.9 M {sub sun} pc{sup -2}. These densities are at the low end of commonly considered thresholds for star formation and imply either that local gas densities are higher before star formation begins or subthreshold star formation is possible. The first casemore » could be explained by supernovae triggering and other local processes, while the second case could be explained by gravitational instabilities with angular momentum loss in growing condensations. The distribution of regions on a log(mass) - log(age) plot is examined. The distribution is usually uniform along log(age) for equal intervals of log(mass) and this implies a region count that varies as 1/age. This variation results from either an individual region mass that varies as 1/age or a region disruption probability that varies as 1/age. A correlation between fading-corrected surface brightness and age suggests the former. The implied loss of mass is from fading of region envelopes below the surface brightness limit.« less
Lustre, hadoop, accumulo

Data processing systems impose multiple views on data as it is processed by the system. These views include spreadsheets, databases, matrices, and graphs. There are a wide variety of technologies that can be used to store and process data through these different steps. The Lustre parallel file system, the Hadoop distributed file system, and the Accumulo database are all designed to address the largest and the most challenging data storage problems. There have been many ad-hoc comparisons of these technologies. This paper describes the foundational principles of each technology, provides simple models for assessing their capabilities, and compares the various technologies on a hypothetical common cluster. These comparisons indicate that Lustre provides 2x more storage capacity, is less likely to loose data during 3 simultaneous drive failures, and provides higher bandwidth on general purpose workloads. Hadoop can provide 4x greater read bandwidth on special purpose workloads. Accumulo provides 105 lower latency on random lookups than either Lustre or Hadoop but Accumulo's bulk bandwidth is 10x less. Significant recent work has been done to enable mix-and-match solutions that allow Lustre, Hadoop, and Accumulo to be combined in different ways.
DEUTERIUM BURNING IN MASSIVE GIANT PLANETS AND LOW-MASS BROWN DWARFS FORMED BY CORE-NUCLEATED ACCRETION

Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M{sub Circled-Plus }, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (M{sub Jup}). After the formation process, which lasts 1-5 Myr and which ends with a ''cold-start'', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M{sub 50}, above which more than 50% of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M{sub 50} fall in the range 11.6-13.6 M{sub Jup}, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yieldingmore » lower values of M{sub 50}. For masses above M{sub 50}, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.« less
Solving Large-Scale Robust Stability Problems by Exploiting the Parallel Structure of Polya's Theorem

In this paper, we propose a distributed computing approach to solving large-scale robust stability problems on the simplex. Our approach is to formulate the robust stability problem as an optimization problem with polynomial variables and polynomial inequality constraints. We use Polya's theorem to convert the polynomial optimization problem to a set of highly structured linear matrix inequalities (LMIs). We then use a slight modification of a common interior-point primal-dual algorithm to solve the structured LMI constraints. This yields a set of extremely large yet structured computations. We then map the structure of the computations to a decentralized computing environment consisting of independent processing nodes with a structured adjacency matrix. The result is an algorithm which can solve the robust stability problem with the same per-core complexity as the deterministic stability problem with a conservatism which is only a function of the number of processors available. Numerical tests on cluster computers and supercomputers demonstrate the ability of the algorithm to efficiently utilize hundreds and potentially thousands of processors and analyze systems with 100+ dimensional state-space. The proposed algorithms can be extended to perform stability analysis of nonlinear systems and robust controller synthesis.
On the Rayleigh–Kuo criterion for the tertiary instability of zonal flows

This paper reports the stability conditions for intense zonal flows (ZFs) and the growth rate γTI of the corresponding “tertiary” instability (TI) within the generalized Hasegawa–Mima plasma model. The analytical calculation extends and revises Kuo's analysis of the mathematically similar barotropic vorticity equation for incompressible neutral fluids on a rotating sphere [H.-L. Kuo, J. Meteor. 6, 105 (1949)]; then, the results are applied to the plasma case. An error in Kuo's original result is pointed out. An explicit analytical formula for γTI is derived and compared with numerical calculations. It is shown that, within the generalized Hasegawa–Mima model, a sinusoidal ZF is TI-unstable if and only if it satisfies the Rayleigh–Kuo criterion (known from geophysics) and that the ZF wave number exceeds the inverse ion sound radius. For non-sinusoidal ZFs, the results are qualitatively similar. As a corollary, there is no TI in the geometrical-optics limit, i.e., when the perturbation wavelength is small compared to the ZF scale. This also means that the traditional wave kinetic equation, which is derived under the geometrical-optics assumption, cannot adequately describe the ZF stability.This paper reports the stability conditions for intense zonal flows (ZFs) and the growth rate γTI of the corresponding “tertiary” instability (TI) within the generalized Hasegawa–Mima plasma model. The analytical calculation extends and revises Kuo's analysis of the mathematically similar barotropic vorticity equation for incompressible neutral fluids on a rotating sphere [H.-L. Kuo, J. Meteor. 6, 105 (1949)]; then, the results are applied to the plasma case. An error in Kuo's original result is pointed out. An explicit analytical formula for γTI is derived and compared with numerical calculations. It is shown that, within the generalized Hasegawa–Mima model, a sinusoidal ZF is TI-unstable if and only if it satisfies the Rayleigh–Kuo criterion (known from geophysics) and that the ZF wave number exceeds the inverse ion sound radius. For non-sinusoidal ZFs, the results are qualitatively similar. As a corollary, there is no TI in the geometrical-optics limit, i.e., when the perturbation wavelength is small c...
The evolution of supernovae in circumstellar wind bubbles. II. Case of a wolf-rayet star

Mass loss from massive stars leads to the formation of circumstellar wind-blown bubbles surrounding the star, bordered by a dense shell. When the star ends its life in a supernova (SN) explosion, the resulting shock wave expands within this modified medium. Following up on an introductory paper (Dwarkadas), herein we study the evolution of a SN in the bubble formed by a 35 M☉ star that evolves through the phases O star, red supergiant, and Wolf-Rayet star. We model the evolution of the circumstellar medium, and the expansion of the SN shock wave within this medium. Our multidimensional simulations clearly reveal density and pressure fluctuations within the surrounding medium, the presence of hydrodynamic instabilities, the growth of vorticity, and the onset of turbulence. The SN shock interaction with this medium, and then with the dense shell, gives rise to transmitted and reflected shocks. Their effect on the X-ray emission is examined. In this particular case the shock wave is trapped in the dense shell for several doubling times. The turbulent interior, coupled with the density and pressure fluctuations, lead to a corrugated SN shock that impacts the dense shell. The impact occurs in a piecemeal fashion, with some parts of the shock wave interacting with the shell before others. As each interaction is accompanied by an increase in the X-ray and optical emission, different parts of the shell will "light up" at different times. The situation is resemblant of the scenario in SN 1987A. The reflected shock formed upon shell impact comprises several smaller shocks with different velocities, which are not necessarily moving radially inward. The spherical symmetry of the initial shock wave is completely destroyed.
Inferring 3D Shapes of Unknown Rigid Objects in Clutter Through Inverse Physics Reasoning

We present a probabilistic approach for building, on the fly, three dimensional (3D) models of unknown objects while being manipulated by a robot. We specifically consider manipulation tasks in piles of clutter that contain previously unseen objects. Most manipulation algorithms for performing such tasks require known geometric models of the objects in order to grasp or rearrange them robustly. One of the novel aspects of this work is the utilization of a physics engine for verifying hypothesized geometries in simulation. The evidence provided by physics simulations is used in a probabilistic framework that accounts for the fact that mechanical properties of the objects are uncertain. We present an efficient algorithm for inferring occluded parts of objects based on their observed motions and mutual interactions. Experiments using a robot show that this approach is efficient for constructing physically realistic 3D models, which can be useful for manipulation planning. Experiments also show that the proposed approach significantly outperforms alternative approaches in terms of shape accuracy.
Families from supergroups and predictions for leptonic CP violation

As was shown in 1984 by Caneschi, Farrar, and Schwimmer, decomposing representations of the supergroup SU(M |N ), can give interesting anomaly-free sets of fermion representations of SU(M ) × SU(N ) × U(1). It is shown here that such groups can be used to construct realistic grand unified models with non-abelian gauged family symmetries. A particularly simple three-family example based on SU(5) × SU(2) × U(1) is studied. The forms of the mass matrices, including that of the right-handed neutrinos, are determined in terms of SU(2) Clebsch coefficients; and the model is able to fit the lepton sector and predict the Dirac CP-violating phase of the neutrinos. Models of this type would have a rich phenomenology if part of the family symmetry is broken near the electroweak scale.
The importance of off-jet relativistic kinematics in gamma-ray burst jet models

GRBs are widely thought to originate from collimated jets of material moving at relativistic velocities. Emission from such a jet should be visible even when viewed from outside the angle of collimation. I summarize recent work on the special relativistic transformation of the burst quantities Eiso (isotropic-equivalent energy of the burst) and Epeak (peak of the burst spectrum in the power νFν) as a function of viewing angle. The resulting formulae serve as input for a Monte Carlo population synthesis method, with which I investigate the importance of off-jet relativistic kinematics as an explanation for a class of GRBs termed X-ray flashes (XRFs) in the context of several top-hat-shaped variable opening-angle jet models. For certain parameters, such models predict a large population of off-jet bursts that are observable and that lie away from the Epeak ∝ E relation. This predicted burst population is not seen in current data sets. I investigate the effect of the bulk γ value on the properties of this population of off-jet bursts, as well as the effect of including an Ω0-Eγ correlation to jointly fit the Epeak ∝ E and Epeak ∝ E relations, where Ω0 is the opening solid angle of the GRB jet. I find that the XRFs seen by HETE-2 and BeppoSAX cannot be easily explained as classical GRBs viewed off-jet. I also find that an inverse correlation between γ and Ω0 has the effect of greatly reducing the visibility of off-jet events. Therefore, unless γ > 300 for all bursts, or there is a strong inverse correlation between γ and Ω0, top-hat variable opening-angle jet models produce a significant population of bursts away from the Epeak ∝ E and Epeak ∝ E relations, in contradiction with current observations.
Optimal simplices and codes in projective spaces

We find many tight codes in compact spaces, in other words, optimal codes whose optimality follows from linear programming bounds. In particular, we show the existence (and abundance) of several hitherto unknown families of simplices in quaternionic projective spaces and the octonionic projective plane. The most noteworthy cases are 15–point simplices in ℍ‘ℙ2 and 27–point simplices in O‘ℙ2, both of which are the largest simplices and the smallest 2–designs possible in their respective spaces. These codes are all universally optimal, by a theorem of Cohn and Kumar. We also show the existence of several positive-dimensional families of simplices in the Grassmannians of subspaces of ℝn with n ≤ 8; close numerical approximations to these families had been found by Conway, Hardin and Sloane, but no proof of existence was known. Our existence proofs are computer-assisted, and the main tool is a variant of the Newton–Kantorovich theorem. This effective implicit function theorem shows, in favorable conditions, that every approximate solution to a set of polynomial equations has a nearby exact solution. Finally, we also exhibit a few explicit codes, including a configuration of 39 points in O‘ℙ2 that form a maximal system of mutually unbiased bases. This is the last tight code in O‘ℙ2 whose existence had been previously conjectured but not resolved.
The Bright Symbiotic Mira EF Aquilae

An incidental spectrum of the poorly studied long-period variable EF Aquilae shows [O III] emission indicative of a symbiotic star. Strong GALEX detections in the UV reinforce this classification, providing overt evidence for the presence of the hot subluminous companion. Recent compilations of the photometric behavior strongly suggest that the cool component is a Mira variable. Thus EF Aql appears to be a member of the rare symbiotic Mira subgroup.
Large-scale continuous subgraph queries on streams

Graph pattern matching involves finding exact or approximate matches for a query subgraph in a larger graph. It has been studied extensively and has strong applications in domains such as computer vision, computational biology, social networks, security and finance. The problem of exact graph pattern matching is often described in terms of subgraph isomorphism which is NP-complete. The exponential growth in streaming data from online social networks, news and video streams and the continual need for situational awareness motivates a solution for finding patterns in streaming updates. This is also the prime driver for the real-time analytics market. Development of incremental algorithms for graph pattern matching on streaming inputs to a continually evolving graph is a nascent area of research. Some of the challenges associated with this problem are the same as found in continuous query (CQ) evaluation on streaming databases. This paper reviews some of the representative work from the exhaustively researched field of CQ systems and identifies important semantics, constraints and architectural features that are also appropriate for HPC systems performing real-time graph analytics. For each of these features we present a brief discussion of the challenge encountered in the database realm, the approach to the solution and state their relevance in a high-performance, streaming graph processing framework.graph of Gd and vertices of Gq such that all vertex adjacencies are preserved. Dynamic graphs refer to graphs that evolve over time through addition or deletion of vertices and edges. Therefore, the problem of graph pattern matching for dynamic graphs can be described as the continuous process of searching for patterns in the graph as it is updated. News [23], finance [7], cyber security and intelligence [10] are among the primary domains that drive the real-time analytics market [1, 19] and motivate development of HPC systems. These domains present data sources that lend themselves naturally to a graph based representation and additionally, provide semantic information in terms of types, labels and timestamps, which can be more generally described as attributes of the vertices and edges of the graph. The availability of the attributes influence the isomorphism computation because assigning a correspondence between a pair of vertices in the search and query graph requires them to satisfy equality constraints on type and possibly, other attributes as well. All these domains are also characterized by massive streaming data that are continuously providing updates from social networks, financial markets and malicious activities on the internet with a high emphasis on time-to-insight, the capability of learning about an event as soon as it happens. This motivates
THE PROPERTIES OF LOW REDSHIFT INTERGALACTIC O VI ABSORBERS DETERMINED FROM HIGH S/N OBSERVATIONS OF 14 QSOs WITH THE COSMIC ORIGINS SPECTROGRAPH*

We report on the observed properties of the plasma revealed through high signal-to-noise observations of 54 intervening O VI absorption systems containing 85 O VI and 133 H I components in a blind survey of 14 QSOs observed at ~18 km s–1 resolution with the Cosmic Origins Spectrograph over a redshift path of 3.52 at z log T > 5) in 14 (31%) of the components. The total hydrogen content of the 14 warm components can be estimated from the temperature and the measured value of log N(H I). The very large implied values of log N(H) range from 18.38 to 20.38 with a median of 19.35. The metallicity, [O/H], in the 6 warm components with log T > 5.45 ranges from –1.93 to 0.03 with a median value of –1.0 dex. Ground-based galaxy redshift studies reveal that most of the absorbers we detect sample gas in the intergalactic medium extending 200 to 600 kpc beyond the closest associated galaxy. For the warm aligned O VI absorbers, we estimate Ωb(O VI)Warm = 0.0019 ± 0.0005 which corresponds to (4.1 ± 1.1)% of the baryons at low z. The warm plasma traced by the aligned O VI and H I absorption contains nearly as many baryons as are found in galaxies.
A Complexity Theory of Constructible Functions and Sheaves

In this paper we introduce constructible analogs of the discrete complexity classes $$\mathbf {VP}$$VP and $$\mathbf {VNP}$$VNP of sequences of functions. The functions in the new definitions are constructible functions on $$\mathbb {R}^n$$Rn or $$\mathbb {C}^n$$Cn. We define a class of sequences of constructible functions that play a role analogous to that of $$\mathbf {VP}$$VP in the more classical theory. The class analogous to $$\mathbf {VNP}$$VNP is defined using Euler integration. We discuss several examples, develop a theory of completeness, and pose a conjecture analogous to the $$\mathbf {VP}$$VP versus $$\mathbf {VNP}$$VNP conjecture in the classical case. In the second part of the paper we extend the notions of complexity classes to sequences of constructible sheaves over $$\mathbb {R}^n$$Rn (or its one point compactification). We introduce a class of sequences of simple constructible sheaves, that could be seen as the sheaf-theoretic analog of the Blum---Shub---Smale class $$\mathbf {P}_\mathbb {R}$$PR. We also define a hierarchy of complexity classes of sheaves mirroring the polynomial hierarchy, $$\mathbf {PH}_\mathbb {R}$$PHR, in the B---S---S theory. We prove a singly exponential upper bound on the topological complexity of the sheaves in this hierarchy mirroring a similar result in the B---S---S setting. We obtain as a result an algorithm with singly exponential complexity for a sheaf-theoretic variant of the real quantifier elimination problem. We pose the natural sheaf-theoretic analogs of the classical $$\mathbf {P}$$P versus $$\mathbf {NP}$$NP question, and also discuss a connection with Toda's theorem from discrete complexity theory in the context of constructible sheaves. We also discuss possible generalizations of the questions in complexity theory related to separation of complexity classes to more general categories via sequences of adjoint pairs of functors.
Multi-impurity polarons in a dilute Bose-Einstein condensate

We describe the ground state of a large, dilute, neutral atom Bose?Einstein condensate (BEC) doped with N strongly coupled mutually indistinguishable, bosonic neutral atoms (referred to as ?impurity?) in the polaron regime where the BEC density response to the impurity atoms remains significantly smaller than the average density of the surrounding BEC. We find that N impurity atoms with N???1 can self-localize at a lower value of the impurity?boson interaction strength than a single impurity atom. When the ?bare? short-range impurity?impurity repulsion does not play a significant role, the self-localization of multiple bosonic impurity atoms into the same single particle orbital (which we call co-self-localization) is the nucleation process of the phase separation transition. When the short-range impurity?impurity repulsion successfully competes with co-self-localization, the system may form a stable liquid of self-localized single impurity polarons.
Constraining sterile neutrinos with a low energy beta-beam

We show that a low energy beta-beam facility can be used to search for sterile neutrinos by measuring the disappearance of electron anti-neutrinos. This channel is particularly sensitive since it allows to use inverse beta decay as detection reaction; thus it is free from hadronic uncertainties, provided the neutrino energy is below the pion production threshold. This corresponds to a choice of the Lorentz γ ≃ 30 for the 6He parent ion. Moreover, a disappearance measurement allows the constraint of sterile neutrino properties independently of any CP violating effects. A moderate detector size of a few 100 tons and ion production rates of ∼2 · 1013 s−1 are sufficient to constrain mixing angles as small as sin2 2θ = 10−2 at 99% confidence level.
Spatially-resolved study of the Meissner effect in superconductors using NV-centers-in-diamond optical magnetometry

Non-invasive magnetic field sensing using optically-detected magnetic resonance of nitrogen-vacancy centers in diamond was used to study spatial distribution of the magnetic induction upon penetration and expulsion of weak magnetic fields in several representative superconductors. Vector magnetic fields were measured on the surface of conventional, elemental Pb and Nb, and compound LuNi2B2C and unconventional iron-based superconductors Ba1−x K x Fe2As2 (x = 0.34 optimal hole doping), Ba(Fe1−x Co x )2As2 (x = 0.07 optimal electron doping), and stoichiometric CaKFe4As4, using variable-temperature confocal system with diffraction-limited spatial resolution. Magnetic induction profiles across the crystal edges were measured in zero-field-cooled and field-cooled conditions. While all superconductors show nearly perfect screening of magnetic fields applied after cooling to temperatures well below the superconducting transition, T c, a range of very different behaviors was observed for Meissner expulsion upon cooling in static magnetic field from above T c. Substantial conventional Meissner expulsion is found in LuNi2B2C, paramagnetic Meissner effect is found in Nb, and virtually no expulsion is observed in iron-based superconductors. In all cases, good correlation with macroscopic measurements of total magnetic moment is found.
Robust predictions for the large-scale cosmological power deficit from primordial quantum nonequilibrium

The de Broglie–Bohm pilot-wave formulation of quantum theory allows the existence of physical states that violate the Born probability rule. Recent work has shown that in pilot-wave field theory on expanding space relaxation to the Born rule is suppressed for long-wavelength field modes, resulting in a large-scale power deficit ξ(k) which for a radiation-dominated expansion is found to have an approximate inverse-tangent dependence on k (assuming that the width of the initial distribution is smaller than the width of the initial Born-rule distribution and that the initial quantum states are evenly-weighted superpositions of energy states). In this paper, we show that the functional form of ξ(k) is robust under changes in the initial nonequilibrium distribution — subject to the limitation of a subquantum width — as well as under the addition of an inflationary era at the end of the radiation-dominated phase. In both cases, the predicted deficit ξ(k) remains an inverse-tangent function of k. Furthermore, with the inflationary phase the dependence of the fitting parameters on the number of superposed pre-inflationary energy states is comparable to that found previously. Our results indicate that, for the assumed broad class of initial conditions, an inverse-tangent power deficit is likely to be a fairly general and robust signature of quantum relaxation in the early universe.
Learning to Approximate a Bregman Divergence

Bregman divergences generalize measures such as the squared Euclidean distance and the KL divergence, and arise throughout many areas of machine learning. In this paper, we focus on the problem of approximating an arbitrary Bregman divergence from supervision, and we provide a well-principled approach to analyzing such approximations. We develop a formulation and algorithm for learning arbitrary Bregman divergences based on approximating their underlying convex generating function via a piecewise linear function. We provide theoretical approximation bounds using our parameterization and show that the generalization error $O_p(m^{-1/2})$ for metric learning using our framework matches the known generalization error in the strictly less general Mahalanobis metric learning setting. We further demonstrate empirically that our method performs well in comparison to existing metric learning methods, particularly for clustering and ranking problems.
Statistical distributions of sequencing by synthesis with probabilistic nucleotide incorporation.

Abstract Sequencing by synthesis is used in many next-generation DNA sequencing technologies. Some of the technologies, especially those exploring the principle of single-molecule sequencing, allow incomplete nucleotide incorporation in each cycle. We derive statistical distributions for sequencing by synthesis by taking into account the possibility that nucleotide incorporation may not be complete in each flow cycle. The statistical distributions are expressed in terms of nucleotide probabilities of the target sequences and the nucleotide incorporation probabilities for each nucleotide. We give exact distributions both for fixed number of flow cycles and for fixed sequence length. Explicit formulas are derived for the mean and variance of these distributions. The results are generalizations of our previous work for pyrosequencing. Incomplete nucleotide incorporation leads to significant change in the mean and variance of the distributions, but still they can be approximated by normal distributions with t...
Statistical description of transport in multimode fibers with mode-dependent loss

We analyze coherent wave transport in a new physical setting associated with multimode wave systems where reflection is completely suppressed and mode-dependent losses together with mode mixing are dictating the wave propagation. An additional physical constraint is the fact that in realistic circumstances the access to the scattering (or transmission) matrix is incomplete. We have addressed all these challenges by providing a statistical description of wave transport which fuses together a free probability theory approach with a filtered random matrix ensemble. Our theoretical predictions have been tested successfully against experimental data of light transport in multimode fibers.
Linear L-Positive Sets and Their Polar Subspaces

In this paper, we define a Banach SNL space to be a Banach space with a certain kind of linear map from it into its dual, and we develop the theory of linear L–positive subsets of Banach SNL spaces with Banach SNL dual spaces. We use this theory to give simplified proofs of some recent results of Bauschke, Borwein, Wang and Yao, and also of the classical Brezis–Browder theorem.
Upper continuity bound on the quantum quasi-relative entropy

We provide an upper bound on the quasi-relative entropy in terms of the trace distance. The bound is derived for any operator monotone decreasing function and either mixed qubit or classical states. Moreover, we derive an upper bound for the Umegaki and Tsallis relative entropies in the case of any finite-dimensional states. The bound for the relative entropy improves the known bounds for some states in any dimensions larger than four. The bound for the Tsallis entropy improves the known bounds.We provide an upper bound on the quasi-relative entropy in terms of the trace distance. The bound is derived for any operator monotone decreasing function and either mixed qubit or classical states. Moreover, we derive an upper bound for the Umegaki and Tsallis relative entropies in the case of any finite-dimensional states. The bound for the relative entropy improves the known bounds for some states in any dimensions larger than four. The bound for the Tsallis entropy improves the known bounds.
Stellar Wind -- Magnetosphere Interactions in Hot Jupiters

One potential star-planet interaction mechanism for hot Jupiters involves planetary heating via currents set up by interactions between the stellar wind and planetary magnetosphere. Early modeling results indicate that such currents, which are analogous to the terrestrial global electric circuit (GEC), have the potential to provide sufficient heating to account for the additional radius inflation seen in some hot Jupiters. Here we present a more detailed model of this phenomenon, exploring the scale of the effect, the circumstances under which it is likely to be significant, implications for the planetary magnetospheric structure, and observational signatures.
Age-structured social interactions enhance radicalization

Disaffected youth are among the most susceptible in espousing extremist ideals, as confirmed by demographic studies. We study age-dependent radicalization via a three-stage model where individuals ...
Observations of the Formation, Development, and Structure of a Current Sheet in an Eruptive Solar Flare

We present AIA observations of a structure we interpret as a current sheet associated with an X4.9 flare and coronal mass ejection that occurred on 2014~February~25 in NOAA Active Region 11990. We characterize the properties of the current sheet, finding that the sheet remains on the order of a few thousand km thick for much of the duration of the event and that its temperature generally ranged between $8-10\,\mathrm{MK}$. We also note the presence of other phenomena believed to be associated with magnetic reconnection in current sheets, including supra-arcade downflows and shrinking loops. We estimate that the rate of reconnection during the event was $M_{A} \approx 0.004-0.007$, a value consistent with model predictions. We conclude with a discussion of the implications of this event for reconnection-based eruption models.
Excitations on wedge states and on the sliver

We study ghost number one excitations on the sliver to investigate the solution of string field actions around the tachyon vacuum. The generalized gluing and resmoothing theorem is used to develop a method for evaluating the effective action for excitations on both the wedge states and the sliver state. We analyze the discrete symmetries of the resulting effective action for excitations on the sliver. The gauge unfixed effective action till level two excitations on the sliver is evaluated. This is done for the case with the BRST operator c0 and c0+(c2+c−2)/2 with excitations purely in the ghost sector. We find that the values of the effective potential at the local maximum lie close by for the zeroth and the second level of approximation. This indicates that level truncation in string field theory around the tachyon vacuum using excitations on the sliver converges for both choices of the BRST operator. It also provides evidence for the conjectured string field theory actions around the tachyon vacuum.
Accurate configurational and kinetic statistics in discrete-time Langevin systems

ABSTRACTWe expand on the previously published Gronbech-Jensen Farago (GJF) thermostat, which is a thermodynamically sound variation on the Stormer-Verlet algorithm for simulating discrete-time Lang...