cssi/SciSciGPT-SciSciNet huggingface dataset:
Constraints on Disk Sizes around Young Intermediate-Mass Stars: Nulling Interferometric Observations of Herbig Ae Objects

Physical models of circumstellar disks surrounding pre-main-sequence stars are currently constrained primarily by the spectral energy distribution of the system. Here we present first results from a survey of nearby Herbig Ae stars using nulling interferometry. We measure the spatial extent of the mid-IR emission for the stars HD 150193, HD 163296, and HD 179218. The results indicate that the size of mid-IR emission around Herbig Ae stars may be much smaller than current models predict. The observations constrain ~90% of the 10 μm flux to be within an approximately 20 AU diameter region, providing significant spatial limits for disk models. These results demonstrate the scientific potential for nulling interferometry to study circumstellar disks with better spatial discernment than is possible with standard mid-IR imaging.
Long-time asymptotics of a Bohmian scalar quantum field in de Sitter space-time

We consider a model quantum field theory with a scalar quantum field in de Sitter space-time in a Bohmian version with a field ontology, i.e., an actual field configuration $$\varphi (\mathbf{x},t)$$ guided by a wave function on the space of field configurations. We analyze the asymptotics at late times ( $$t\rightarrow \infty $$ ) and provide reason to believe that for more or less any wave function and initial field configuration, every Fourier coefficient $$\varphi _\mathbf{k}(t)$$ of the field is asymptotically of the form $$c_\mathbf{k}\sqrt{1+\mathbf{k}^2 \exp (-2Ht)/H^2}$$ , where the limiting coefficients $$c_\mathbf{k}=\varphi _\mathbf{k}(\infty )$$ are independent of t and H is the Hubble constant quantifying the expansion rate of de Sitter space-time. In particular, every field mode $$\varphi _\mathbf{k}$$ possesses a limit as $$t\rightarrow \infty $$ and thus “freezes.” This result is relevant to the question whether Boltzmann brains form in the late universe according to this theory, and supports that they do not.
GALACTIC STRUCTURE AND STELLAR POPULATIONS

The Milky Way Galaxy offers a unique opportunity for testing theories of galaxy formation and evolution. I discuss how large surveys, both photometric and spectroscopic, of Galactic stars are the keystones of investigations into such fundamental problems as the merging history--and future--of the Galaxy.
The Importance of Tau Leptons for Supersymmetry Searches at the Tevatron

Supersymmetry is perhaps most effectively probed at the Tevatron through production and decay of weak gauginos. Most of the analyses of weak gaugino observables require electrons or muons in the final state. However it is possible that the gauginos will decay primarily to τ leptons, thus complicating the search for supersymmetry. The motivating reasons for high τ multiplicity final states are discussed in three approaches to supersymmetry model building: minimal supergravity, minimal gauge mediated supersymmetry, and more minimal supersymmetry. The concept of "e/μ/τ candidate" is introduced, and an observable with three e/μ/τ candidates is defined in analog to the trilepton observable. The maximum mass reach for supersymmetry is then estimated when gaugino decays to τ leptons have full branching fraction.
Planar and curved droplet networks

We study how a two-dimensional square sheet of droplets evolves to the preferred triangular lattice. The rearrangement can be induced either by an impurity seed for flat sheets or by curving the sheet. We analyze the propagation of transformation fronts and the spatial reordering subsequent to the initial perturbation.
Universality at the edge of the spectrum for unitary, orthogonal, and symplectic ensembles of random matrices

We prove universality at the edge of the spectrum for unitary (β = 2), orthogonal (β = 1), and symplectic (β = 4) ensembles of random matrices in the scaling limit for a class of weights w(x) = e−V(x) where V is a polynomial, V(x) = κ2mx2m + · · ·, κ2m > 0. The precise statement of our results is given in Theorem 1.1 and Corollaries 1.2 and 1.4 below. For the same class of weights, a proof of universality in the bulk of the spectrum is given in [12] for the unitary ensembles and in [9] for the orthogonal and symplectic ensembles. Our starting point in the unitary case is [12], and for the orthogonal and symplectic cases we rely on our recent work [9], which in turn depends on the earlier work of Widom [46] and Tracy and Widom [42]. As in [9], the uniform Plancherel-Rotach-type asymptotics for the orthogonal polynomials found in [12] plays a central role. The formulae in [46] express the correlation kernels for β = 1, 4 as a sum of a Christoffel-Darboux (CD) term, as in the case β = 2, together with a correction term. In the bulk scaling limit [9], the correction term is of lower order and does not contribute to the limiting form of the correlation kernel. By contrast, in the edge scaling limit considered here, the CD term and the correction term contribute to the same order: this leads to additional technical difficulties over and above [49]. © 2006 Wiley Periodicals, Inc.
Review of Soft Interactions and Multiparticle Correlations

Recent developments in the area of soft interactions and multiparticle correlations are reviewed, including higher harmonic flows conjectured to result from the initial-state geometry which might coincide with some jet-like correlation features in more-central A-A collisions.
The Future of Direct Supermassive Black Hole Mass Estimates

The repeated discovery of supermassive black holes (SMBHs) at the centers of galactic bulges, and the discovery of relations between the SMBH mass (M•) and the properties of these bulges, have been fundamental in directing our understanding of both galaxy and SMBH formation and evolution. However, there are still many underlying questions surrounding the SMBH-galaxy relations. For example, are the scaling relations linear and constant throughout cosmic history, and do all SMBHs lie on the scaling relations? These fundamental questions can only be answered by further high quality direct M• estimates from a wide range in redshift, before further refinements to galaxy evolution models can be made. In this article we determine the observational requirements necessary to directly determine SMBH masses, across cosmological distances, using current M• modeling techniques. We also discuss the SMBH detection abilities of future facilities. We find that if different M• modeling techniques, using different spectral features, can be shown to be consistent, then both 30 m ground-based and 16 m space-based telescopes will theoretically be able to sample M• ~ 109M⊙ across ~95% of cosmic history. In addition, SMBHs as small as 106M⊙ will be sampled at a distance of the Coma cluster, and SMBHs as small as 104M⊙ will be sampled in the Local Group. However, we find that the abilities of ground-based telescopes critically depend on future advancements in adaptive optics systems; more limited AO systems will result in limited effective spatial resolutions, i.e., SMBH detection efficiency, and will force observations toward the near-infrared where spectral features are weaker and more susceptible to sky features. Ground-based AO systems will always be constrained by relatively bright sky backgrounds and atmospheric transmission. The latter forces the use of multiple spectral features and dramatically impacts the SMBH detection efficiency. The most efficient way to advance our database of direct SMBH masses is therefore through the use of a large (16 m) space-based UVOIR telescope.
Radiative Thermal Runaway Due to Negative-Differential Thermal Emission Across a Solid-Solid Phase Transition

Thermal runaway is a positive-feedback phenomenon observed in many contexts, including fluid boiling and self-heating in semiconductors. Leveraging the insulator-metal phase transition of VO${}_{2}$, the authors characterize the dynamics of thermal runaway when heat is dissipated from an emitter through far-field thermal radiation. By minimizing the emitter's thermal mass, they show that rapid thermal switching is achievable. Further enhancements may be possible using near-field radiation. This description of the switching dynamics associated with radiative thermal runaway may enable the design of advanced infrared sensors, thermal diodes, and calorimeters.
Variational procedure and generalized Lanczos recursion for small-amplitude classical oscillations

A variational procedure is developed which yields the lowest frequencies of small-amplitude oscillations of classical Hamiltonian systems. The genuine Lanczos recursion is generalized to treat related non-Hermitian eigenvalue problems.
Theoretical Approach to Electroresistance in Ferroelectric Tunnel Junctions

Ferroelectric tunnel junctions (FTJs) are of keen interest for next-generation electronics. This work presents a theoretical approach to describe polarization-dependent tunneling electroresistance (TER), and to explain the controversy of the opposite signs of TER observed experimentally by various groups. The model also can be directly extended to explore possible mechanisms responsible for the memristor effect in FTJs. This work informs not only our basic understanding of these devices, but also the design of nonvolatile memory and memristor circuits based on FTJs.
Tri-comb spectroscopy

Multidimensional coherent spectroscopy (MDCS)1,2 is a powerful method that enables the measurement of homogeneous linewidths in inhomogenously broadened systems, many-body interactions and coupling between excited resonances, all of which are not simultaneously accessible by any other method. Current implementations of MDCS require a bulky apparatus and suffer from resolution and acquisition speed limitations that constrain their applications outside the laboratory3–5. Here, we propose and demonstrate an approach to nonlinear coherent spectroscopy that utilizes three slightly different repetition-rate frequency combs. Unlike traditional nonlinear methods, tri-comb spectroscopy uses only a single photodetector and no mechanical moving elements to enable faster acquisition times, while also providing comb resolution. As a proof of concept, a multidimensional coherent spectrum with comb cross-diagonal resolution is generated using only 365 ms of data. These improvements make MDCS relevant for systems with narrow resonances and it has the potential to be field deployable for chemical-sensing applications. A nonlinear coherent spectroscopy that uses three slightly different repetition-rate frequency combs is demonstrated. A 2D spectrum with comb resolution is generated using only 365 milliseconds of data, almost 600 times faster than previous approaches.
A local-global principle in the dynamics of quadratic polynomials

Let K be a number field, f ∈ K[x] a quadratic polynomial, and n ∈{1, 2, 3}. We show that if f has a point of period n in every non-archimedean completion of K, then f has a point of period n in K. For n ∈{4, 5} we show that there exist at most finitely many linear conjugacy classes of quadratic polynomials over K for which this local–global principle fails. By considering a stronger form of this principle, we strengthen global results obtained by Morton and Flynn–Poonen–Schaefer in the case K = Q. More precisely, we show that for every quadratic polynomial f ∈Q[x] there exist infinitely many primes p such that f does not have a point of period four in the p-adic field Qp. Conditional on knowing all rational points on a particular curve of genus 11, the same result is proved for points of period five.
GEVR: An Event Venue Recommendation System for Groups of Mobile Users

In this paper, we present GEVR, the first Group Event Venue Recommendation system that incorporates mobility via individual location traces and context information into a "social-based" group decision model to provide venue recommendations for groups of mobile users. Our study leverages a real-world dataset collected using the OutWithFriendz mobile app for group event planning, which contains 625 users and over 500 group events. We first develop a novel "social-based" group location prediction model, which adaptively applies different group decision strategies to groups with different social relationship strength to aggregate each group member's location preference, to predict where groups will meet. Evaluation results show that our prediction model not only outperforms commonly used and state-of-the-art group decision strategies with over 80% accuracy for predicting groups' final meeting location clusters, but also provides promising qualities in cold-start scenarios. We then integrate our prediction model with the Foursquare Venue Recommendation API to construct an event venue recommendation framework for groups of mobile users. Evaluation results show that GEVR outperforms the comparative models by a significant margin.
Spontaneous emission of electric and magnetic dipoles in the vicinity of thin and thick metal

Strong modification of spontaneous emission of Eu3+ ions placed in close vicinity to thin and thick gold and silver films was clearly demonstrated in a microscope setup separately for electric and magnetic dipole transitions. We have shown that the magnetic transition was very sensitive to the thickness of the gold substrate and behaved distinctly different from the electric transition. The observations were described theoretically based on the dyadic Green’s function approach for layered media and explained through modified image models for the near and far-field emissions. We established that there exists a “near-field event horizon”, which demarcates the distance from the metal at which the dipole emission is taken up exclusively in the near field.
Spreading processes over socio-technical networks with phase-type transmissions

Most theoretical tools available for the analysis of spreading processes over networks assume exponentially distributed transmission and recovery times. In practice, the empirical distribution of transmission times for many real spreading processes, such as the spread of web content through the Internet, are far from exponential. To bridge this gap between theory and practice, we propose a methodology to model and analyze spreading processes with arbitrary transmission times using phase-type distributions. Phase-type distributions are a family of distributions that is dense in the set of positive-valued distributions and can be used to approximate any given distributions. To illustrate our methodology, we focus on a popular model of spreading over networks: the susceptible-infected-susceptible (SIS) networked model. In the standard version of this model, individuals informed about a piece of information transmit this piece to its neighbors at an exponential rate. In this paper, we extend this model to the case of transmission rates following a phase-type distribution. Using this extended model, we analyze the dynamics of the spread based on a vectorial representations of phase-type distributions. We illustrate our results by analyzing spreading processes over networks with transmission and recovery rates following a Weibull distribution.
Uniform constants in Hausdorff-Young inequalities for the Cantor group model of the scattering transform

Analogues of Hausdorff-Young inequalities for the Dirac scattering transform (a.k.a. SU(1, 1) nonlinear Fourier transform) were first established by Christ and Kiselev. Later Muscalu, Tao, and Thiele raised a question if the constants can be chosen uniformly in 1≤p≤2. Here we give a positive answer to that question when the Euclidean real line is replaced by its Cantor group model.
Quantum Theory and the Limits of Objectivity

Three recent arguments seek to show that the universal applicability of unitary quantum theory is inconsistent with the assumption that a well-conducted measurement always has a definite physical outcome. In this paper I restate and analyze these arguments. The import of the first two is diminished by their dependence on assumptions about the outcomes of counterfactual measurements. But the third argument establishes its intended conclusion. Even if every well-conducted quantum measurement we ever make will have a definite physical outcome, this argument should make us reconsider the objectivity of that outcome.
Knowledge Authoring and Question Answering with KALM

Knowledge representation and reasoning (KRR) is one of the key areas in artificial intelligence (AI) field. It is intended to represent the world knowledge in formal languages (e.g., Prolog, SPARQL) and then enhance the expert systems to perform querying and inference tasks. Currently, constructing large scale knowledge bases (KBs) with high quality is prohibited by the fact that the construction process requires many qualified knowledge engineers who not only understand the domain-specific knowledge but also have sufficient skills in knowledge representation. Unfortunately, qualified knowledge engineers are in short supply. Therefore, it would be very useful to build a tool that allows the user to construct and query the KB simply via text. Although there is a number of systems developed for knowledge extraction and question answering, they mainly fail in that these system don't achieve high enough accuracy whereas KRR is highly sensitive to erroneous data. In this thesis proposal, I will present Knowledge Authoring Logic Machine (KALM), a rule-based system which allows the user to author knowledge and query the KB in text. The experimental results show that KALM achieved superior accuracy in knowledge authoring and question answering as compared to the state-of-the-art systems.
Avoided Mode Crossings in Cylindrical Microwave Cavities

The $a\phantom{\rule{0}{0ex}}x\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n$ particle is one of the most promising candidates for the constitution of cold dark matter. As researchers of axion dark matter continue to scan for higher masses, the detectors become more sensitive to anomalous effects, which could confound the search. This analysis examines the effects of breaking translational invariance within cylindrical microwave cavities similar to those typically used in haloscope detectors. Breaking translational invariance causes avoided mode crossings, a discovery that enables experiments to mitigate these effects in the detectors used in the axion quest.
Design of a Monolithic Low-Threshold Narrow-Linewidth CW Mid-IR Silicon Raman Laser

We present a design and calculations leading to anticipated values of key performance parameters (threshold pump powers, wavelength, and linewidths) for an optically-pumped narrow-linewidth (NLW) monolithic all-silicon mid-IR (MIR) continuous wave (CW) Raman laser. For an NLW laser designed to operate at $3.15~\mu \text{m}$ (based on a $2.71~\mu \text{m}$ pump laser), we estimate the threshold pump power to be <10 mW and an output linewidth of <50 MHz.
Stars Get Dizzy After Lunch

Exoplanet searches have discovered a large number of ’hot Jupiters’–high-mass planets orbiting very close to their parent stars in nearly circular orbits. A number of these planets are sufficiently massive and close-in to be significantly affected by tidal dissipation in the parent star, to a degree parametrized by the tidal quality factor Q∗. This process speeds up their stars’ rotation rate while reducing the planets’ semimajor axis. In this paper, we investigate the tidal destruction of hot Jupiters. Because the orbital angular momenta of these planets are a significant fraction of their stars’ rotational angular momenta, they spin up their stars significantly while spiralling to their deaths. Using Monte Carlo simulation, we predict that for Q∗ = 10 6 , 3.9 × 10 −6 of stars with the Kepler Target Catalog’s mass distribution should have a rotation period shorter than 1/3 day (8 h) due to accreting a planet. Exoplanet surveys such as SuperWASP, HATnet, HATsouth, and KELT have already produced light curves of millions of stars. These two facts suggest that it may be possible to search for tidally-destroyed planets by looking for stars with extremely short rotational periods, then looking for remnant planet cores around those candidates, anomalies in the metal distribution, or other signatures of the recent accretion of the planet.
Stable ODE-type blowup for some quasilinear wave equations with derivative-quadratic nonlinearities

We prove a constructive stable ODE-type blowup-result for open sets of solutions to a family of quasilinear wave equations in three spatial dimensions. The blowup is driven by a Riccati-type derivative-quadratic semilinear term, and the singularity is more severe than a shock in that the solution itself blows up like the log of the distance to the blowup-time. We assume that the quasilinear terms satisfy certain structural assumptions, which in particular ensure that the “elliptic part” of the wave operator vanishes precisely at the singular points. The initial data are compactly supported and can be small or large in L∞ in an absolute sense, but we assume that their spatial derivatives satisfy a nonlinear smallness condition relative to the size of the time derivative. The first main idea of the proof is to construct a quasilinear integrating factor, which allows us to reformulate the wave equation as a first-order system whose solutions remain regular, all the way up to the singularity. Using the integrating factor, we construct quasilinear vector fields adapted to the nonlinear flow. The second main idea is to exploit some crucial monotonic terms in various estimates, especially the energy estimates, that feature the integrating factor. The availability of the monotonicity is tied to our size assumptions on the initial data and on the structure of the nonlinear terms. The third main idea is to propagate the relative smallness of the spatial derivatives all the way up to the singularity so that the solution behaves, in many ways, like an ODE solution. As a corollary of our main results, we show that there are quasilinear wave equations that exhibit two distinct kinds of blowup: the formation of shocks for one nontrivial set of data, and ODE-type blowup for another nontrivial set.
On Minkowski type question mark functions associated with even or odd continued fractions

We study analogues of Minkowski’s question mark function ?(x) related to continued fractions with even or with odd partial quotients. We prove that these functions are Holder continuous with precise exponents, and that they linearize the appropriate versions of the Gauss and Farey maps.
Effects of soft interactions and bound mobility on diffusion in crowded environments: a model of sticky and slippery obstacles

Crowded environments modify the diffusion of macromolecules, generally slowing their movement and inducing transient anomalous subdiffusion. The presence of obstacles also modifies the kinetics and equilibrium behavior of tracers. While previous theoretical studies of particle diffusion have typically assumed either impenetrable obstacles or binding interactions that immobilize the particle, in many cellular contexts bound particles remain mobile. Examples include membrane proteins or lipids with some entry and diffusion within lipid domains and proteins that can enter into membraneless organelles or compartments such as the nucleolus. Using a lattice model, we studied the diffusive movement of tracer particles which bind to soft obstacles, allowing tracers and obstacles to occupy the same lattice site. For sticky obstacles, bound tracer particles are immobile, while for slippery obstacles, bound tracers can hop without penalty to adjacent obstacles. In both models, binding significantly alters tracer motion. The type and degree of motion while bound is a key determinant of the tracer mobility: slippery obstacles can allow nearly unhindered diffusion, even at high obstacle filling fraction. To mimic compartmentalization in a cell, we examined how obstacle size and a range of bound diffusion coefficients affect tracer dynamics. The behavior of the model is similar in two and three spatial dimensions. Our work has implications for protein movement and interactions within cells.
Trisecting 4–manifolds

We show that any smooth, closed, oriented, connected 4‐manifold can be trisected into three copies of \ k .S 1 B 3 /, intersecting pairwise in 3‐dimensional handlebodies, with triple intersection a closed 2‐dimensional surface. Such a trisection is unique up to a natural stabilization operation. This is analogous to the existence, and uniqueness up to stabilization, of Heegaard splittings of 3‐manifolds. A trisection of a 4‐manifold X arises from a Morse 2‐function GW X! B 2 and the obvious trisection of B 2 , in much the same way that a Heegaard splitting of a 3‐manifold Y arises from a Morse function gW Y ! B 1 and the obvious bisection of B 1 .
Quantum vacua of 2d maximally supersymmetric Yang-Mills theory

We analyze the classical and quantum vacua of 2d N=(8,8) supersymmetric Yang-Mills theory with SU(N) and U(N) gauge group, describing the worldvolume interactions of Nparallel D1-branes with flat transverse directions R^8. We claim that the IR limit of the SU(N) theory in the superselection sector labeled M (mod N) — identified with the internal dynamics of (M, N)-string bound states of the Type IIB string theory — is described by the symmetric orbifold N=(8,8) sigma model into (R^8)^(D−1)/S_D when D = gcd(M, N) > 1, and by a single massive vacuum when D = 1, generalizing the conjectures of E. Witten and others. The full worldvolume theory of the D1-branes is the U(N) theory with an additional U(1) 2-form gauge field B coming from the string theory Kalb-Ramond field. This U(N) + B theory has generalized field configurations, labeled by the Z-valued generalized electric flux and an independent Z_N-valued ’t Hooft flux. We argue that in the quantum mechanical theory, the (M, N)-string sector with M units of electric flux has a Z_N-valued discrete θ angle specified by M (mod N) dual to the ’t Hooft flux. Adding the brane center-of-mass degrees of freedom to the SU(N) theory, we claim that the IR limit of the U(N) + B theory in the sector with M bound F-strings is described by the N=(8,8) sigma model into Sym^D(R^8). We provide strong evidence for these claims by computing an N=(8,8) analog of the elliptic genus of the UV gauge theories and of their conjectured IR limit sigma models, and showing they agree. Agreement is established by noting that the elliptic genera are modular-invariant Abelian (multi-periodic and meromorphic) functions, which turns out to be very restrictive.
Penalized orthogonal-components regression for large p small n data

Here we propose a penalized orthogonal-componentsregression (POCRE) for large p small n data. Orthogonal components are sequentially constructed to maximize, upon standardization, their correlation to the re- sponse residuals. A new penalization framework, implemented via empiri- cal Bayes thresholding, is presented to effectively identify sparse predictors of each component. POCRE is computationally efficient owing t its se- quential construction of leading sparse principal components. In addition, such construction offers other properties such as grouping highly correlated predictors and allowing for collinear or nearly collinear predictors. With multivariate responses, POCRE can construct common components and thus build up latent-variable models for large p small n data. AMS 2000 subject classifications: Primary 62J05; secondary 62H20,
Near-field nanoprobing using Si tip-Au nanoparticle photoinduced force microscopy with 120:1 signal-to-noise ratio, sub-6-nm resolution

We propose using a Si tip-Au nanoparticle (NP) combination system in photoinduced force microscopy (PiFM) to fundamentally improve its accuracy in the nanoscale characterization of light-matter interaction. Compared to conventional PiFM with Au-coated tips, such Si tip and Au NP combination enables superior photo-induced force detection while overcoming the tip-induced anisotropy by Au-coating. We map the near-field distribution of Au NPs in different arrangements achieving 120 signal-to-noise ratio and sub-6-nm resolution, even surpassing the tip-curvature limitation; we also map the azimuthally polarized beam profile showing an excellent symmetry. The proposed approach is essential to the promising single molecule spectroscopy.
Open Gromov-Witten Invariants of Toric Calabi-Yau 3-Folds

We present a proof of the mirror conjecture of Aganagic and Vafa (Mirror Symmetry, D-Branes and Counting Holomorphic Discs. http://arxiv.org/abs/hep-th/0012041v1, 2000) and Aganagic et al. (Z Naturforsch A 57(1–2):128, 2002) on disk enumeration in toric Calabi-Yau 3-folds for all smooth semi-projective toric Calabi-Yau 3-folds. We consider both inner and outer branes, at arbitrary framing. In particular, we recover previous results on the conjecture for (i) an inner brane at zero framing in \({K_{\mathbb{P}^2}}\) (Graber-Zaslow, Contemp Math 310:107–121, 2002), (ii) an outer brane at arbitrary framing in the resolved conifold \({\mathcal{O}_{\mathbb{P}^1}(-1)\oplus \mathcal{O}_{\mathbb{P}^1}(-1)}\) (Zhou, Open string invariants and mirror curve of the resolved conifold. http://arxiv.org/abs/1001.0447v1 [math.AG], 2010), and (iii) an outer brane at zero framing in \({K_{\mathbb{P}^2}}\) (Brini, Open topological strings and integrable hierarchies: Remodeling the A-model. http://arxiv.org/abs/1102.0281 [hep-th], 2011).
Measuring Information Propagation in Literary Social Networks

We present the task of modeling information propagation in literature, in which we seek to identify pieces of information passing from character A to character B to character C, only given a description of their activity in text. We describe a new pipeline for measuring information propagation in this domain and publish a new dataset for speaker attribution, enabling the evaluation of an important component of this pipeline on a wider range of literary texts than previously studied. Using this pipeline, we analyze the dynamics of information propagation in over 5,000 works of fiction, finding that information flows through characters that fill structural holes connecting different communities, and that characters who are women are depicted as filling this role much more frequently than characters who are men.
On the reach of perturbative methods for dark matter density fields

We study the mapping from Lagrangian to Eulerian space in the context of the Effective Field Theory (EFT) of Large Scale Structure. We compute Lagrangian displacements with Lagrangian Perturbation Theory (LPT) and perform the full non-perturbative transformation from displacement to density. When expanded up to a given order, this transformation reproduces the standard Eulerian Perturbation Theory (SPT) at the same order. However, the full transformation from displacement to density also includes higher order terms. These terms explicitly resum long wavelength motions, thus making the resulting density field better correlated with the true non-linear density field. As a result, the regime of validity of this approach is expected to extend that of the Eulerian EFT, and match that of the IR-resummed Eulerian EFT. This approach thus effectively enables a test of the IR-resummed EFT at the field level. We estimate the size of stochastic, non-perturbative contributions to the matter density power spectrum. We find that in our highest order calculation, at redshift z = 0 the power spectrum of the density field is reproduced with an accuracy of 1% (10%) up to k = 0.25 hMpc−1 (k = 0.46 hMpc−1). We believe that the dominant source of the remaining error is the stochastic contribution. Unfortunately, on these scales the stochastic term does not yet scale as k4 as it does in the very low k regime. Thus, modeling this contribution might be challenging.
The Degree of Alignment between Circumbinary Disks and Their Binary Hosts

All four circumbinary (CB) protoplanetary disks orbiting short-period ($P < 20$ day) double-lined spectroscopic binaries (SB2s)---a group that includes UZ Tau E, for which we present new ALMA data---exhibit sky-plane inclinations $i_{\rm disk}$ which match, to within a few degrees, the sky-plane inclinations $i_\star$ of their stellar hosts. Although for these systems the true mutual inclinations $\theta$ between disk and binary cannot be directly measured because relative nodal angles are unknown, the near-coincidence of $i_{\rm disk}$ and $i_\star$ suggests that $\theta$ is small for these most compact of systems. We confirm this hypothesis using a hierarchical Bayesian analysis, showing that 68% of CB disks around short-period SB2s have $\theta < 3.0^\circ$. Near co-planarity of CB disks implies near co-planarity of CB planets discovered by Kepler, which in turn implies that the occurrence rate of close-in CB planets is similar to that around single stars. By contrast, at longer periods ranging from $30-10^5$ days (where the nodal degeneracy can be broken via, e.g., binary astrometry), CB disks exhibit a wide range of mutual inclinations, from co-planar to polar. Many of these long-period binaries are eccentric, as their component stars are too far separated to be tidally circularized. We discuss how theories of binary formation and disk-binary gravitational interactions can accommodate all these observations.
Open-shell coupled-cluster valence-bond theory augmented with an independent amplitude approximation for three-pair correlations: Application to a model oxygen-evolving complex and single molecular magnet

We report the failure of coupled-cluster valence-bond (CCVB) theory with two-pair configurations [D. W. Small and M. Head-Gordon, J. Chem. Phys. 130, 084103 (2009)] for open-shell (OS) spin-frustrated systems where including three-pair configurations is necessary to properly describe strong spin-correlations. We extend OS-CCVB by augmenting the model with three-pair configurations within the independent amplitude approximation. The resulting new electronic structure model, OS-CCVB+i3, involves only a quadratic number of independent wavefunction parameters. It includes the recently reported closed-shell CCVB+i3 as a special case. Its cost is dominated by integral transformations, and it is capable of breaking multiple bonds exactly for all systems examined so far. The strength of OS-CCVB+i3 is highlighted in realistic systems including the [CaMn3O4] cubane subunit of the oxygen-evolving complex and a molecular magnet with the [Cr9] core unit as well as model systems such as N3, V3O3, and P5. We show that OS-CCVB+i3 is only slightly dependent on the underlying perfect-pairing reference, while OS-CCVB shows a stronger dependence. We also emphasize the compactness of the OS-CCVB+i3 wavefunction compared to the heat-bath configuration interaction wavefunction, a recently introduced soft exponential-scaling approach.
Spectral clustering and the high-dimensional stochastic blockmodel

Networks or graphs can easily represent a diverse set of data sources that are characterized by interacting units or actors. Social ne tworks, representing people who communicate with each other, are one example. Communities or clusters of highly connected actors form an essential feature in the structure of several empirical networks. Spectral clustering is a popular and computationally feasi ble method to discover these communities. The Stochastic Block Model (Holland et al., 1983) is a social network model with well defined communities; each node is a member of one community. For a network generated from the Stochastic Block Model, we bound the number of nodes "misclus- tered" by spectral clustering. The asymptotic results in th is paper are the first clustering results that allow the number of clusters in the model to grow with the number of nodes, hence the name high-dimensional. In order to study spectral clustering under the Stochastic Block Model, we first show that under the more general latent space model, the eigenvectors of the normalized graph Laplacian asymptotically converge to the eigenvectors of a "population" normal- ized graph Laplacian. Aside from the implication for spectral clustering, this provides insight into a graph visualization technique. Our method of studying the eigenvectors of random matrices is original. AMS 2000 subject classifications: Primary 62H30, 62H25; secondary 60B20.
New Cosmological Model and Its Implications on Observational Data Interpretation

The paradigm of CDM cosmology works impressively well and with the concept of inflation it explains the universe after the time of decoupling. However there are still a few concerns; after much e ort there is no detection of dark matter and there are significant problems in the theoretical description of dark energy. We will consider a variant of the cosmological spherical shell model, within FRW formalism and will com- pare it with the standard CDM model. We will show that our new topological model satisfies cosmological principles and is consistent with all observable data, but that it may require new interpretation for some data. Considered will be constraints imposed on the model, as for instance the range for the size and allowed thickness of the shell, by the supernovae luminosity distance and CMB data. In this model propagation of the light is confined along the shell, which has as a consequence that observed CMB originated from one point or a limited space region. It allows to interpret the uniformity of the CMB with- out inflation scenario. In addition this removes any constraints on the uniformity of the universe at the early stage and opens a possibility that the universe was not uniform and that creation of galaxies and large structures is due to the inhomogeneities that originated in the Big Bang.
Resolved Millimeter Observations of the HR 8799 Debris Disk

We present 1.3 millimeter observations of the debris disk surrounding the HR 8799 multi-planet system from the Submillimeter Array to complement archival ALMA observations that spatially filtered away the bulk of the emission. The image morphology at $3.8$ arcsecond (150 AU) resolution indicates an optically thin circumstellar belt, which we associate with a population of dust-producing planetesimals within the debris disk. The interferometric visibilities are fit well by an axisymmetric radial power-law model characterized by a broad width, $\Delta R/R\gtrsim 1$. The belt inclination and orientation parameters are consistent with the planet orbital parameters within the mutual uncertainties. The models constrain the radial location of the inner edge of the belt to $R_\text{in}= 104_{-12}^{+8}$ AU. In a simple scenario where the chaotic zone of the outermost planet b truncates the planetesimal distribution, this inner edge location translates into a constraint on the planet~b mass of $M_\text{pl} = 5.8_{-3.1}^{+7.9}$ M$_{\rm Jup}$. This mass estimate is consistent with infrared observations of the planet luminosity and standard hot-start evolutionary models, with the uncertainties allowing for a range of initial conditions. We also present new 9 millimeter observations of the debris disk from the Very Large Array and determine a millimeter spectral index of $2.41\pm0.17$. This value is typical of debris disks and indicates a power-law index of the grain size distribution $q=3.27\pm0.10$, close to predictions for a classical collisional cascade.
Implications of Rapid Core Rotation in Red Giants for Internal Angular Momentum Transport in Stars

Core rotation rates have been measured for red giant stars using asteroseismology. These data, along with helioseismic measurements and open cluster spin-down studies, provide powerful clues about the nature and timescale for internal angular momentum transport in stars. We focus on two cases: the metal-poor red giant KIC 7341231 ("Otto") and intermediate-mass core helium burning stars. For both, we examine limiting case studies for angular momentum coupling between cores and envelopes under the assumption of rigid rotation on the main sequence. We discuss the expected pattern of core rotation as a function of mass and radius. In the case of Otto, strong post-main-sequence coupling is ruled out and the measured core rotation rate is in the range of 23-33 times the surface value expected from standard spin-down models. The minimum coupling timescale (0.17-0.45 Gyr) is significantly longer than that inferred for young open cluster stars. This implies ineffective internal angular momentum transport in early first ascent giants. By contrast, the core rotation rates of evolved secondary clump stars are found to be consistent with strong coupling given their rapid main-sequence rotation. An extrapolation to the white dwarf regime predicts rotation periods between 330 and 0.0052 days, depending on mass and decoupling time. We identify two key ingredients that explain these features: the presence of a convective core and inefficient angular momentum transport in the presence of larger mean molecular weight gradients. Observational tests that can disentangle these effects are discussed.
Reinstating the M31 X-Ray System RX J0042.3+4115 as a Black Hole X-Ray Binary and Compelling Evidence for an Extended Corona

The M31 X-ray source RX J0042.3+4115 was originally identified as a black hole (BH) binary because it displayed characteristic low-state variability at conspicuously high luminosities; unfortunately, this variability was later found to be artificial. However, analysis of 84 Chandra ACIS observations, a Hubble Space Telescope Advanced Camera for Surveys (ACS)/WFC observation, and a 60 ks XMM-Newton observation has supplied new evidence that RX J0042.3+4115 is indeed a BH binary. The brightest optical star within 3σ of the position of RXJ0042.3+4115 had a F435W (~B) magnitude of 25.4 ± 0.2; M B > –0.4, hence we find a low-mass donor likely. RX J0042.3+4115 was persistently bright over ~12 years. Spectral fits revealed characteristic BH binary states: a low/hard state at 2.08 ± 0.08 × 1038 erg s–1 and a steep power-law state at 2.41 ± 0.05 × 1038 erg s–1 (0.3-10 keV). The high-luminosity low state suggests a ~20 M ☉ primary; this is high, but within the range of known stellar BH masses. The inner disk temperature during the steep power-law state is 2.24 ± 0.15 keV, high but strikingly similar to that of GRS 1915+105, the only known Galactic BH binary with a low-mass donor to be persistently bright. Therefore, RX J0042.3+4115 may be an analog for GRS 1915+105; however, other mechanisms may account for its behavior. We find compelling evidence for an extended corona during the steep power-law state, because compact corona models where the seed photons for Comptonization are tied to the inner disk temperature are rejected.
Fractal Analyses of Networks of Integrate-and-Fire Stochastic Spiking Neurons

Although there is increasing evidence of criticality in the brain, the processes that guide neuronal networks to reach or maintain criticality remain unclear. The present research examines the role of neuronal gain plasticity in time-series of simulated neuronal networks composed of integrate-and-fire stochastic spiking neurons and the utility of fractal methods in assessing network criticality. Simulated time-series were derived from a network model of fully connected discrete-time stochastic excitable neurons. Monofractal and multifractal analyses were applied to neuronal gain time-series. Fractal scaling was greatest in networks with a mid-range of neuronal plasticity, versus extremely high or low levels of plasticity. Peak fractal scaling corresponded closely to additional indices of criticality, including average branching ratio. Networks exhibited multifractal structure, or multiple scaling relationships. Multifractal spectra around peak criticality exhibited elongated right tails, suggesting that the fractal structure is relatively insensitive to high-amplitude local fluctuations. Networks near critical states exhibited mid-range multifractal spectra width and tail length, which is consistent with the literature suggesting that networks poised at quasi-critical states must be stable enough to maintain organization but unstable enough to be adaptable. Lastly, fractal analyses may offer additional information about critical state dynamics of networks by indicating scales of influence as networks approach critical states.
SELF-GENERATED TURBULENCE IN MAGNETIC RECONNECTION

Classical Sweet-Parker models of reconnection predict that reconnection rates depend inversely on the resistivity, usually parameterized using the dimensionless Lundquist number (S). We describe magnetohydrodynamic (MHD) simulations using a static, nested grid that show the development of a three-dimensional instability in the plane of a current sheet between reversing eld lines without a guide eld. The instability leads to rapid reconnection of magnetic eld lines at a rate independent of S over at least the range 3:2 10 3 . S . 3:2 10 5 resolved by the simulations. We nd that this instability occurs even for cases with S . 10 4 that in our models appear stable to the recently described, two-dimensional, plasmoid instability. Our results suggest that three-dimensional, MHD processes alone produce fast (resistivity independent) reconnection without recourse to kinetic eects or external turbulence. The unstable reconnection layers provide a self-consistent environment in which the extensively studied turbulent reconnection process can occur.
Yang–Mills theory over surfaces and the Atiyah–Segal theorem

In this paper we explain how Morse theory for the Yang–Mills functional can be used to prove an analogue, for surface groups, of the Atiyah–Segal theorem. Classically, the Atiyah–Segal theorem relates the representation ring R(Γ) of a compact Lie group Γ to the complex K –theory of the classifying space BΓ . For infinite discrete groups, it is necessary to take into account deformations of representations, and with this in mind we replace the representation ring by Carlsson’s deformation K –theory spectrum Kdef(Γ) (the homotopy-theoretical analogue of R(Γ)). Our main theorem provides an isomorphism in homotopy Kdef ∗ (π1Σ) ∼= K−∗(Σ) for all compact, aspherical surfaces Σ and all ∗ > 0. Combining this result with work of Tyler Lawson, we obtain homotopy theoretical information about the stable moduli space of flat unitary connections over surfaces.
Integer complexity: the integer defect

Define ∥n∥ to be the complexity of n, the smallest number of 1s needed to write n using an arbitrary combination of addition and multiplication. John Selfridge showed that ∥n∥≥3log3n for all n, leading this author and Zelinsky to define the defect of n, δ(n), to be the difference ∥n∥−3log3n. Meanwhile, in the study of addition chains, it is common to consider s(n), the number of small steps of n, defined as l(n)−⌊log2n⌋, an integer quantity, where l(n) is the length of the shortest addition chain for n. So here we analogously define D(n), the integer defect of n, an integer version of δ(n) analogous to s(n). Note that D(n) is not the same as ⌈δ(n)⌉. We show that D(n) has additional meaning in terms of the defect well-ordering we considered in 2015, in that D(n) indicates which powers of ω the quantity δ(n) lies between when one restricts to n with ∥n∥ lying in a specified congruence class modulo 3. We also determine all numbers n with D(n)≤1, and use this to generalize a result of Rawsthorne (1989).
Holographic thermodynamics at finite baryon density: some exact results

We use the AdS/CFT correspondence to study the thermodynamics of massive = 2 supersymmetric hypermultiplets coupled to = 4 supersymmetric SU(Nc) Yang-Mills theory in the limits of large Nc and large 't Hooft coupling. In particular, we study the theory at finite baryon number density. At zero temperature, we present an exact expression for the hypermultiplets' leading-order contribution to the free energy, and in the supergravity description we clarify which D-brane configuration is appropriate for any given value of the chemical potential. We find a second-order phase transition when the chemical potential equals the mass. At finite temperature, we present an exact expression for the hypermultiplets' leading-order contribution to the free energy at zero mass.