cssi/SciSciGPT-SciSciNet huggingface dataset:
Modeling the Impact of 5G Leakage on Weather Prediction

The 5G band allocated in the 26 GHz spectrum referred to as 3GPP band n258, has generated a lot of anxiety and concern in the meteorological data forecasting community including the National Oceanic and Atmospheric Administration (NOAA). Unlike traditional spectrum coexistence problems, the issue here stems from the leakage of n258 band transmissions impacting the observations of passive sensors (e.g. AMSU-A) operating at 23.8 GHz on weather satellites used to detect the amount of water vapor in the atmosphere, which in turn affects weather forecasting and predictions. In this paper, we study the impact of 5G leakage on the accuracy of data assimilation based weather prediction algorithms by using a first order propagation model to characterize the effect of the leakage signal on the brightness temperature (atmospheric radiance) and the induced noise temperature at the receiving antenna of the passive sensor (radiometer) on the weather observation satellite. We then characterize the resulting inaccuracies when using the Weather Research and Forecasting Data Assimilation model (WRFDA) to predict temperature and rainfall. For example, the impact of 5G leakage of -20dBW to -15dBW on the well-known Super Tuesday Tornado Outbreak data set, affects the meteorological forecasting up to 0.9 mm in precipitation and $1.3^{\circ}\mathrm{C}$ in 2m-temperature. We outline future directions for both improved modeling of 5G leakage effects as well as mitigation using cross-layer antenna techniques coupled with resource allocation.
Adaptation and the Boundary of Multinational Firms

This paper offers the first empirical analysis of the impact of adaptation on the boundary of multinational firms. To do so, we develop a ranking of sectors in terms of "“routineness"” by merging two sets of data: ratings of occupations by their intensities in solving problems from the U.S. Department of Labor's Occupational Information Network and U.S. employment shares of occupations by sectors from the Bureau of Labor Statistics Occupational Employment Statistics. Using U.S. Census trade data, we demonstrate that the share of intrafirm trade tends to be higher in less routine sectors. © 2011 The President and Fellows of Harvard College and the Massachusetts Institute of Technology.
Active-Learning in the Online Environment

Online learning is convenient for many learners; it gives them the possibility of learning without being restricted by attending a particular classroom at a specific time. While this exciting opportunity can let its users manage their life in a better way, many students may suffer from feeling isolated or disconnected from the community that consists of the instructor and the learners. Lack of interaction among students and the instructor may negatively impact their learnings and cause adverse emotions like anxiety, sadness, and depression. Apart from the feeling of loneliness, sometimes students may come up with different issues or questions as they study the course, which can stop them from confidently progressing or make them feel discouraged if we leave them alone. To promote interaction and to overcome the limitations of geographic distance in online education, we propose a customized design, Tele-instruction, with useful features supplement to the traditional online learning systems to enable peers and the instructor of the course to interact at their conveniences once needed. The designed system can help students address their questions through the answers already provided to other students or ask for the instructor's point of view by two-way communication, similar to face-to-face forms of educational experiences. We believe our approach can assist in filling the gaps when online learning falls behind the traditional classroom-based learning systems.
Machine learning–assisted global optimization of photonic devices

Abstract Over the past decade, artificially engineered optical materials and nanostructured thin films have revolutionized the area of photonics by employing novel concepts of metamaterials and metasurfaces where spatially varying structures yield tailorable “by design” effective electromagnetic properties. The current state-of-the-art approach to designing and optimizing such structures relies heavily on simplistic, intuitive shapes for their unit cells or metaatoms. Such an approach cannot provide the global solution to a complex optimization problem where metaatom shape, in-plane geometry, out-of-plane architecture, and constituent materials have to be properly chosen to yield the maximum performance. In this work, we present a novel machine learning–assisted global optimization framework for photonic metadevice design. We demonstrate that using an adversarial autoencoder (AAE) coupled with a metaheuristic optimization framework significantly enhances the optimization search efficiency of the metadevice configurations with complex topologies. We showcase the concept of physics-driven compressed design space engineering that introduces advanced regularization into the compressed space of an AAE based on the optical responses of the devices. Beyond the significant advancement of the global optimization schemes, our approach can assist in gaining comprehensive design “intuition” by revealing the underlying physics of the optical performance of metadevices with complex topologies and material compositions.
IMPROVED BACKGROUND SUBTRACTION FOR THE SLOAN DIGITAL SKY SURVEY IMAGES

We describe a procedure for background subtracting Sloan Digital Sky Survey (SDSS) imaging that improves the resulting detection and photometry of large galaxies on the sky. Within each SDSS drift scan run, we mask out detected sources and then fit a smooth function to the variation of the sky background. This procedure has been applied to all SDSS-III Data Release 8 images, and the results are available as part of that data set. We have tested the effect of our background subtraction on the photometry of large galaxies by inserting fake galaxies into the raw pixels, reanalyzing the data, and measuring them after background subtraction. Our technique results in no size-dependent bias in galaxy fluxes up to half-light radii r 50 ~ 100 arcsec; in contrast, for galaxies of that size the standard SDSS photometric catalog underestimates fluxes by about 1.5 mag. Our results represent a substantial improvement over the standard SDSS catalog results and should form the basis of any analysis of nearby galaxies using the SDSS imaging data.
Quantitative equidistribution for certain quadruples in quasi-random groups

In my recent paper [1] there is a mistake in the proof of Corollary 3. The first line of the displayed equation in that proof asserts that \[\int_G|\langle u,\pi^g v\rangle_V|^2\,\rm{d} g = \int_G\langle u\otimes u,(\pi^g\otimes \pi^g)(v\otimes v)\rangle_{V\otimes V}\, \rm{d} g.\] However, since the paper uses complex-valued representations, the integrand on the right here may not retain the absolute value of that on the left. Without this equality, the proof of Corollary 3 can no longer be reduced to an application of Lemma 2. However, it can be proved directly from Schur Orthogonality along very similar lines to the proof of Lemma 2.
Polarization conversion in a silica microsphere.

We experimentally demonstrate controlled polarization-selective phenomena in a whispering gallery mode resonator. We observed efficient (≈75%) polarization conversion of light in a silica microsphere coupled to a tapered optical fiber with proper optimization of the polarization of the propagating light. A simple model treating the microsphere as a ring resonator provides a good fit to the observed behavior.
Anisotropic evolution of D-dimensional FRW spacetime

We examine the time evolution of the $$D=d+4$$ dimensional Einstein field equations subjected to a flat Robertson-Walker metric where the 3D and higher-dimensional scale factors are allowed to evolve at different rates. We find the exact solution to these equations for a single fluid component, which yields two limiting regimes offering the 3D scale factor as a function of the time. The fluid regime solution closely mimics that described by 4D FRW cosmology, offering a late-time behavior for the 3D scale factor after becoming valid in the early universe, and can give rise to a late-time accelerated expansion driven by vacuum energy. This is shown to be preceded by an earlier volume regime solution, which offers a very early-time epoch of accelerated expansion for a radiation-dominated universe for $$d=1$$. The time scales describing these phenomena, including the transition from volume to fluid regime, are shown to fall within a small fraction of the first second when the fundamental constants of the theory are aligned with the Planck time. This model potentially offers a higher-dimensional alternative to scalar-field inflationary theory and a consistent cosmological theory, yielding a unified description of early- and late-time accelerated expansions via a 5D spacetime scenario.
Trivial centralizers for codimension-one attractors

We show that if Λ is a codimension-one hyperbolic attractor for a Cr diffeomorphism f , where 2 ≤ r ≤ ∞, and f is not Anosov, then there is a neighborhood U of f in Diffr(M) and an open and dense set V of U such that any g ∈ V has a trivial centralizer on the basin of attraction for Λ.
Measure partitions via Fourier analysis II: center transversality in the {{L}^{2}}-norm for complex hyperplanes

Applications of harmonic analysis on finite groups were recently introduced to measure partition problems, with a variety of equipartition types by convex fundamental domains obtained as the vanishing of prescribed Fourier transforms. Considering the circle group, we extend this approach to the compact Lie group setting, in which case the annihilation of transforms in the classical Fourier series produces measure transversality similar in spirit to the classical centerpoint theorem of Rado: for any $${q\geq 2}$$ , the existence of a complex hyperplane whose surrounding regular q-fans are close—in an $${L^2}$$ -sense—to equipartitioning a given set of measures. The proofs of these results represent the first application of continuous as opposed to finite group actions in the usual equivariant topological reductions prevalent in combinatorial geometry.
Learning to Execute Programs with Instruction Pointer Attention Graph Neural Networks

Graph neural networks (GNNs) have emerged as a powerful tool for learning software engineering tasks including code completion, bug finding, and program repair. They benefit from leveraging program structure like control flow graphs, but they are not well-suited to tasks like program execution that require far more sequential reasoning steps than number of GNN propagation steps. Recurrent neural networks (RNNs), on the other hand, are well-suited to long sequential chains of reasoning, but they do not naturally incorporate program structure and generally perform worse on the above tasks. Our aim is to achieve the best of both worlds, and we do so by introducing a novel GNN architecture, the Instruction Pointer Attention Graph Neural Networks (IPA-GNN), which achieves improved systematic generalization on the task of learning to execute programs using control flow graphs. The model arises by considering RNNs operating on program traces with branch decisions as latent variables. The IPA-GNN can be seen either as a continuous relaxation of the RNN model or as a GNN variant more tailored to execution. To test the models, we propose evaluating systematic generalization on learning to execute using control flow graphs, which tests sequential reasoning and use of program structure. More practically, we evaluate these models on the task of learning to execute partial programs, as might arise if using the model as a heuristic function in program synthesis. Results show that the IPA-GNN outperforms a variety of RNN and GNN baselines on both tasks.
Assessing pulsar timing array sensitivity to gravitational wave bursts with memory

Highly energetic astrophysical phenomena like supermassive black hole binary (SMBHB) mergers are predicted to emit prodigious amounts of gravitational waves (GWs). An anticipated component of the gravitational waveform known as "memory" is permanent and nonoscillatory. For SMBHB mergers, the memory is created primarily during the most violent moments of the inspiral immediately preceding the final plunge and ring-down when the strongest gravitational fields are at work and the nonlinearities of general relativity are most pronounced. The essentially time-domain nature of memory makes it forbiddingly difficult to detect with ground based GW detectors, leaving pulsar timing array (PTA) experiments as the most promising means by which it may be detected and studied. In this paper, we discuss how GW bursts with memory (BWMs) influence pulsar timing experiments and develop methods to assess how sensitive modern timing efforts are to such GW events. We discuss how PTA searches for BWMs can be used to constrain the rate of BWMs and how these constraints relate to information regarding the population of SMBHBs.
Rigidification of quasi-categories

We give a new construction for rigidifying a quasi-category into a simplicial category, and prove that it is weakly equivalent to the rigidification given by Lurie. Our construction comes from the use of necklaces, which are simplicial sets obtained by stringing simplices together. As an application of these methods, we use our model to reprove some basic facts from Lurie [Annals of Math. Studies 170 (2009)] about the rigidification process.
Complex Velocity Fields in the Shell of T Pyxidis

We present spatially resolved, moderate-resolution spectrophotometry of the recurrent nova T Pyxidis and a portion of the surrounding shell. The spectrum extracted from a strip of width 10'' centered on the star shows well-known, strong emission lines typical of old novae plus a prominent, unfamiliar emission line at 6590 A. This line, and a weaker companion at 6540 A, which we also detect, has been previously reported by Shahbaz et al. and attributed to Doppler-shifted Hα emission from a collimated jet emerging from T Pyx. We demonstrate that these lines are instead due to [N II] λλ6548, 6584 from a complex velocity field in the surrounding nebula. The comments of past workers concerning the great strength of He II λ4686 in T Pyx itself are also reiterated.
Low-energy effective field theory below the electroweak scale: matching at one loop

We compute the one-loop matching between the Standard Model Effective Field Theory and the low-energy effective field theory below the electroweak scale, where the heavy gauge bosons, the Higgs particle, and the top quark are integrated out. The complete set of matching equations is derived including effects up to dimension six in the power counting of both theories. We present the results for general flavor structures and include both the C P -even and C P -odd sectors. The matching equations express the masses, gauge couplings, as well as the coefficients of dipole, three-gluon, and four-fermion operators in the low-energy theory in terms of the parameters of the Standard Model Effective Field Theory. Using momentum insertion, we also obtain the matching for the C P -violating theta angles. Our results provide an ingredient for a model-independent analysis of constraints on physics beyond the Standard Model. They can be used for fixed- order calculations at one-loop accuracy and represent a first step towards a systematic next-to-leading-log analysis.
Interplay between hydrodynamics and the free energy surface in the assembly of nanoscale hydrophobes.

Solvent plays an important role in the relative motion of nanoscopic bodies, and the study of such phenomena can help elucidate the mechanism of hydrophobic assembly, as well as the influence of so...
Emergent gauge dynamics of highly frustrated magnets

Condensed matter exhibits a wide variety of exotic emergent phenomena such as the fractional quantum Hall effect and the low temperature cooperative behavior of highly frustrated magnets. I consider the classical Hamiltonian dynamics of spins of the latter phenomena using a method introduced by Dirac in the 1950s by assuming they are constrained to their lowest energy configurations as a simplifying measure. Focusing on the kagome antiferromagnet as an example, I find it is a gauge system with topological dynamics and non-locally connected edge states for certain open boundary conditions similar to doubled Chern–Simons electrodynamics expected of a Z2 spin liquid. These dynamics are also similar to electrons in the fractional quantum Hall effect. The classical theory presented here is a first step toward a controlled semi-classical description of the spin liquid phases of many pyrochlore and kagome antiferromagnets and toward a description of the low energy classical dynamics of the corresponding unconstrained Heisenberg models.
A T-odd observable sensitive to CP violating phases in squark decay

We present a new observable sensitive to a certain combination of CP violating phases in supersymmetric extensions of the Standard Model, viz. a triple product of momenta in the cascade decay of a heavy squark via an on-shell neutralino and off-shell slepton. We investigate the regions of parameter space in which the signal is strong enough to be detectable at the LHC with ~ (102−103)/sin 2(2Δ) identified events, where Δ is a certain combination of phases in the MSSM presented in the text.
The Minkowski Formula and the Quasi-Local Mass

In this article, we estimate the quasi-local energy with reference to the Minkowski spacetime (Wang and Yau in Phys Rev Lett 102(2):021101, 2009; Commun Math Phys 288(3):919–942, 2009), the anti-de Sitter spacetime (Chen et al. in Commun Anal Geom, 2016. arXiv:1603.02975 ), or the Schwarzschild spacetime (Chen et al. in Adv Theor Math Phys 22(1):1–23, 2018). In each case, the reference spacetime admits a conformal Killing–Yano 2-form which facilitates the application of the Minkowski formula in Wang et al. (J Differ Geom 105(2):249–290, 2017) to estimate the quasi-local energy. As a consequence of the positive mass theorems in Liu and Yau (J Am Math Soc 19(1):181–204, 2006) and Shi and Tam (Class Quantum Gravity 24(9):2357–2366, 2007) and the above estimate, we obtain rigidity theorems which characterize the Minkowski spacetime and the hyperbolic space.
Maximum likelihood estimation in log-linear models

We study maximum likelihood estimation in log-linear models under conditional Poisson sampling schemes. We derive necessary and sufficient conditions for existence of the maximum likelihood estimator (MLE) of the model parameters and investigate estimability of the natural and mean-value parameters under a nonexistent MLE. Our conditions focus on the role of sampling zeros in the observed table. We situate our results within the framework of extended exponential families, and we exploit the geometric properties of log-linear models. We propose algorithms for extended maximum likelihood estimation that improve and correct the existing algorithms for log-linear model analysis.
Weyl symmetry and the Liouville theory

The flat-space conformal invariance and the curved-space Weyl invariance are simply related in dimensions greater than two. In two dimensions, the Liouville theory presents an exceptional situation, which we examine here.
PROMPT BETA SPECTROSCOPY AS A DIAGNOSTIC FOR MIX IN IGNITED NIF CAPSULES

The National Ignition Facility (NIF) technology is designed to drive deuterium–tritium (DT) internal confinement fusion (ICF) targets to ignition using indirect radiation from laser beam energy captured in a hohlraum. Hydrodynamical instabilities at interfaces in the ICF capsule leading to mix between the DT fuel and the ablator shell material are of fundamental physical interest and can affect the performance characteristics of the capsule. Here we describe new radiochemical diagnostics for mix processes in ICF capsules with plastic or Be(0.9% Cu) ablator shells. Reactions of high-energy tritons with shell material produce high-energy β-emitters. We show that mix between the DT fuel and the shell material enhances high-energy prompt beta emission from these reactions by more than an order of magnitude over that expected in the absence of mix. We further show how a mix signal could be detectable in an ignition failure regime corresponding to yields greater than about 2 kJ.
The Picard group of topological modular forms via descent theory

This paper starts with an exposition of descent-theoretic techniques in the study of Picard groups of E∞–ring spectra, which naturally lead to the study of Picard spectra. We then develop tools for the efficient and explicit determination of differentials in the associated descent spectral sequences for the Picard spectra thus obtained. As a major application, we calculate the Picard groups of the periodic spectrum of topological modular forms TMF and the nonperiodic and nonconnective Tmf. We find that Pic(TMF) is cyclic of order 576, generated by the suspension ΣTMF (a result originally due to Hopkins), while Pic(Tmf) = ℤ ⊕ ℤ∕24. In particular, we show that there exists an invertible Tmf–module which is not equivalent to a suspension of Tmf.
Wrinkled fibrations on near-symplectic manifolds

Motivated by the programmes initiated by Taubes and Perutz, we study the geometry of near-symplectic 4–manifolds, ie, manifolds equipped with a closed 2–form which is symplectic outside a union of embedded 1–dimensional submanifolds, and broken Lefschetz fibrations on them; see Auroux, Donaldson and Katzarkov [3] and Gay and Kirby [8]. We present a set of four moves which allow us to pass from any given broken fibration to any other which is deformation equivalent to it. Moreover, we study the change of the near-symplectic geometry under each of these moves. The arguments rely on the introduction of a more general class of maps, which we call wrinkled fibrations and which allow us to rely on classical singularity theory. Finally, we illustrate these constructions by showing how one can merge components of the zero-set of the near-symplectic form. We also disprove a conjecture of Gay and Kirby by showing that any achiral broken Lefschetz fibration can be turned into a broken Lefschetz fibration by applying a sequence of our moves.
Measurement and Quantum Dynamics in the Minimal Modal Interpretation of Quantum Theory

Any realist interpretation of quantum theory must grapple with the measurement problem and the status of state-vector collapse. In a no-collapse approach, measurement is typically modeled as a dynamical process involving decoherence. We describe how the minimal modal interpretation closes a gap in this dynamical description, leading to a complete and consistent resolution to the measurement problem and an effective form of state collapse. Our interpretation also provides insight into the indivisible nature of measurement—the fact that you can’t stop a measurement part-way through and uncover the underlying ‘ontic’ dynamics of the system in question. Having discussed the hidden dynamics of a system’s ontic state during measurement, we turn to more general forms of open-system dynamics and explore the extent to which the details of the underlying ontic behavior of a system can be described. We construct a space of ontic trajectories and describe obstructions to defining a probability measure on this space.
DETECTING TRANSITS OF PLANETARY COMPANIONS TO GIANT STARS

Of the approximately 350 extrasolar planets currently known, of order 10% orbit evolved stars with radii R * 2.5 R ?. These planets are of particular interest because they tend to orbit more massive hosts, and have been subjected to variable stellar insolation over their recent histories as their primaries evolved off the main sequence. Unfortunately, we have limited information about the physical properties of these planets, as they were all detected by the radial velocity method and none have been observed to transit. Here, we evaluate the prospects for detecting transits of planetary companions to giant stars. We show that several of the known systems have a priori transit probabilities of 10%, and about one transiting system is expected for the sample of host stars with R * ? 2.5 R ?. Although the transits are expected to have very small amplitudes (~few ? 10?4) and long durations (50 hr), we argue that the difficulty with detecting these signals in broadband light is one of systematic errors and practicality rather than photon noise, even for modest aperture (~1 m) telescopes. We propose a novel method that may overcome these difficulties, which uses narrowband measurements to isolate the thin ring of chromospheric emission expected at the limb of giant stars. The transit signals in these narrow bands are expected to be larger in magnitude and briefer in duration than in broadband emission, and thus alleviating many of the difficulties with transit detection in broadband emission. Finally, we point out that it may be possible to discover planetary companions to giant stars using Kepler, provided that a sufficient number of such targets are monitored.
Dynamics of anti-de Sitter domain walls

We study solutions corresponding to moving domain walls in the Randall-Sundrum universe. The bulk geometry is given by patching together black hole solutions in AdS5, and the motion of the wall is determined from the junction equations. Observers on the wall interpret the motion as cosmological expansion or contraction. We describe the possible wall trajectories, and examine the consequences for localized gravity on the wall.
Looking for the logarithms in four-dimensional Nambu-Jona-Lasinio models

Abstract We study the problem of triviality in the four-dimensional Nambu-Jona-Lasinio model with discrete chiral symmetry using both large- N expansions and lattice simulations. We find that logarithmic corrections to scaling appear in the equation of state as predicted by the large- N expansion. The data from 16 4 lattice simulations is sufficiently accurate to distinguish logarithmically trivial scaling from power law scaling. Simulations on different lattice sizes reveal an interesting interplay of finite size effects and triviality. We argue that such effects are qualitatively different for theories based on fundamental scalar rather than fermion fields. Several lessons learned here can be applied to simulations and analyses of more challenging field theories.
On Microscopic Derivation of a Fractional Stochastic Burgers Equation

We derive, from a class of asymmetric mass-conservative interacting particle systems on \({\mathbb{Z}}\), with long-range jump rates of order | · |−(1+α) for 0 < α < 2, different continuum fractional SPDEs. More specifically, we show the equilibrium fluctuations of the hydrodynamics mass density field of zero-range processes, depending on the structure of the asymmetry, and whether the field is translated with process characteristics velocity, are governed in various senses by types of fractional stochastic heat or Burgers equations. The main result: suppose the jump rate is such that its symmetrization is long-range but its (weak) asymmetry is nearest-neighbor. Then, when α < 3/2, the fluctuation field in space-time scale 1/α : 1, translated with process characteristic velocity, irrespective of the strength of the asymmetry, converges to a fractional stochastic heat equation, the limit also for the symmetric process. However, when α ≥ 3/2 and the strength of the weak asymmetry is tuned in scale 1 – 3/2α, the associated limit points satisfy a martingale formulation of a fractional stochastic Burgers equation.
Active colloids in complex fluids

Abstract We review recent work on active colloids or swimmers, such as self-propelled microorganisms, phoretic colloidal particles, and artificial micro-robotic systems, moving in fluid-like environments. These environments can be water-like and Newtonian but can frequently contain macromolecules, flexible polymers, soft cells, or hard particles, which impart complex, nonlinear rheological features to the fluid. While significant progress has been made on understanding how active colloids move and interact in Newtonian fluids, little is known on how active colloids behave in complex and non-Newtonian fluids. An emerging literature is starting to show how fluid rheology can dramatically change the gaits and speeds of individual swimmers. Simultaneously, a moving swimmer induces time dependent, three dimensional fluid flows that can modify the medium (fluid) rheological properties. This two-way, non-linear coupling at microscopic scales has profound implications at meso- and macro-scales: steady state suspension properties, emergent collective behavior, and transport of passive tracer particles. Recent exciting theoretical results and current debate on quantifying these complex active fluids highlight the need for conceptually simple experiments to guide our understanding.
Reorientable Spin Direction for Spin Current Produced by the Anomalous Hall Effect

Generating spin currents with controllable spin direction is important to spin-torque technology, which includes spin-based computing and magnetic random-access memory, but it is difficult to produce such currents through conventional means, like the spin Hall effect. This study shows that the anomalous Hall effect can be used to yield spin currents with controllable spin polarization. The magnetization of the generating ferromagnetic layer, and hence the spin polarization, is governed by exchange bias and external field. This result offers a great deal of flexibility in creating spin torque, which should enable innovative device designs.
The Quintuplet Cluster: Extended Structure and Tidal Radius

Author(s): Rui, NZ; Hosek, MW; Lu, JR; Clarkson, WI; Anderson, J; Morris, MR; Ghez, AM | Abstract: The Quintuplet star cluster is one of only three known young (l10 Myr) massive (M g 104 M o) clusters within ∼100 pc of the Galactic center (GC). In order to explore star cluster formation and evolution in this extreme environment, we analyze the Quintuplet's dynamical structure. Using the HST WFC3-IR instrument, we take astrometric and photometric observations of the Quintuplet covering a 120″ × 120″ field of view, which is 19 times larger than those of previous proper-motion studies of the Quintuplet. We generate a catalog of the Quintuplet region with multiband, near-infrared photometry, proper motions, and cluster membership probabilities for 10,543 stars. We present the radial density profile of 715 candidate Quintuplet cluster members with M ≈ 4.7 M o out to 3.2 pc from the cluster center. A 3σ lower limit of 3 pc is placed on the tidal radius, indicating the lack of a tidal truncation within this radius range. Only weak evidence for mass segregation is found, in contrast to the strong mass segregation found in the Arches cluster, a second and slightly younger massive cluster near the GC. It is possible that tidal stripping hampers a mass segregation signature, though we find no evidence of spatial asymmetry. Assuming that the Arches and Quintuplet clusters formed with comparable extent, our measurement of the Quintuplet's comparatively large core radius of pc provides strong empirical evidence that young massive clusters in the GC dissolve on a several-megayear timescale.
Experimental measurements of atmospheric neutrinos

Abstract This talk reports the latest indications of an anomaly in the measurements of atmospheric neutrinos. New results from Soudan-2 and Super-Kamiokande provide evidence that the ratio of ν μ to ν e interactions is not as expected. High energy Super-Kamiokande data indicates the cause is a deficit of upward-going ν μ , and the zenith angle dependence of the effect is consistent with neutrino oscillations. Upward-going muon measurements by several detectors are discussed, but in total they provide inconclusive evidence for the anomaly.
INTERACTING BOSE AND FERMI GASES IN LOW DIMENSIONS AND THE RIEMANN HYPOTHESIS

We apply the S-matrix based finite temperature formalism to nonrelativistic Bose and Fermi gases in 1+1 and 2+1 dimensions. For the (2+1)-dimensional case in the constant scattering length approximation, the free energy is given in terms of Roger's dilogarithm in a way analagous to the thermodynamic Bethe ansatz for the relativistic (1+1)-dimensional case. The 1d fermionic case with a quasiperiodic two-body potential is closely connected with the Riemann hypothesis.
Recursive starlight and bias estimation for high-contrast imaging with an extended Kalman filter

For imaging faint exoplanets and disks, a coronagraph-equipped observatory needs focal plane wavefront correction to recover high contrast. The most efficient correction methods iteratively estimate the stellar electric field and suppress it with active optics. The estimation requires several images from the science camera per iteration. To maximize the science yield, it is desirable both to have fast wavefront correction and to utilize all the correction images for science target detection. Exoplanets and disks are incoherent with their stars, so a nonlinear estimator is required to estimate both the incoherent intensity and the stellar electric field. Such techniques assume a high level of stability found only on space-based observatories and possibly ground-based telescopes with extreme adaptive optics. In this paper, we implement a nonlinear estimator, the iterated extended Kalman filter (IEKF), to enable fast wavefront correction and a recursive, nearly-optimal estimate of the incoherent light. In Princeton’s High Contrast Imaging Laboratory, we demonstrate that the IEKF allows wavefront correction at least as fast as with a Kalman filter and provides the most accurate detection of a faint companion. The nonlinear IEKF formalism allows us to pursue other strategies such as parameter estimation to improve wavefront correction.
Finitely constrained groups of maximal Hausdorff dimension

We prove that if G_P is a finitely constrained group of binary rooted tree automorphisms (a group binary tree subshift of finite type) defined by an essential pattern group P of pattern size d, d>1, and if G_P has maximal Hausdorff dimension (equal to 1-1/2^{d-1}), then G_P is not topologically finitely generated. We describe precisely all essential pattern groups P that yield finitely constrained groups with maximal Haudorff dimension. For a given size d, d>1, there are exactly 2^{d-1} such pattern groups and they are all maximal in the group of automorphisms of the finite rooted regular tree of depth d.
Inhomogeneity in barrier height at graphene/ Si (GaAs) Schottky junctions

Graphene (Gr) interfaced with a semiconductor forms a Schottky junction with rectifying properties, however, fluctuations in the Schottky barrier height are often observed. In this work, Schottky junctions are fabricated by transferring chemical vapor deposited monolayer Gr onto ntype Si and GaAs substrates. Temperature dependence of the barrier height and ideality factor are obtained by current–voltage measurements between 215 and 350 K. An increase in the zero bias barrier height and decrease in the ideality factor are observed with increasing temperature for both junctions. Such behavior is attributed to barrier inhomogeneities that arise from interfacial disorders as revealed by scanning tunneling microscopy/spectroscopy. Assuming a Gaussian distribution of the barrier heights, mean values of 1.14±0.14 eV and 0.76±0.10 eV are found for Gr/Si and Gr/GaAs junctions, respectively. These findings resolve the origin of barrier height inhomogeneities in these Schottky junctions.
A method for studying initial geometry fluctuations via event plane correlations in heavy ion collisions

A method is proposed to measure the relative azimuthal angle distributions involving two or more event planes of different order in heavy ion collisions using a Fourier analysis technique. The analysis procedure is demonstrated for correlations involving two and three event planes (Φ n , Φ m and Φ h ). The Fourier coefficients of these distributions are found to coincide with previously proposed correlators, such as cos(6Φ 2−6Φ 3) and cos(Φ 1+2Φ 2−3Φ 3) etc., hence the method provides a natural framework for studying these correlators at the same time. Using a Monte Carlo Glauber model to simulate Au+Au collisions with fluctuating initial geometry, we are able to identify several new two- or three-plane correlators that have sizable magnitudes and should be measured experimentally.
Coulomb branches of star-shaped quivers

We study the Coulomb branches of 3d $$ \mathcal{N}=4 $$ “star-shaped” quiver gauge theories and their deformation quantizations, by applying algebraic techniques that have been developed in the mathematics and physics literature over the last few years. The algebraic techniques supply an abelianization map, which embeds the Coulomb-branch chiral ring into a vastly simpler abelian algebra $$ \mathcal{A} $$ . Relations among chiral-ring operators, and their deformation quantization, are canonically induced from the embedding into $$ \mathcal{A} $$ . In the case of star-shaped quivers — whose Coulomb branches are related to Higgs branches of 4d $$ \mathcal{N}=2 $$ theories of Class $$ \mathcal{S} $$ — this allows us to systematically verify known relations, to generalize them, and to quantize them. In the quantized setting, we find several new families of relations.
Passivity degradation in discrete control implementations: An approximate bisimulation approach

In this paper, we present some preliminary results for compositional analysis of heterogeneous systems containing both discrete state models and continuous systems using consistent notions of dissipativity and passivity. We study the following problem: given a physical plant model and a continuous feedback controller designed using traditional control techniques, how is the closed-loop passivity affected when the continuous controller is replaced by a discrete (i.e., symbolic) implementation within this framework? Specifically, we give quantitative results on performance degradation when the discrete control implementation is approximately bisimilar to the continuous controller, and based on them, we provide conditions that guarantee the boundedness property of the closed-loop system.
Synthesis of convection velocity and turbulence measurements in three-stream jets

Key flow regions linked to jet noise sources are investigated through comparison of convection velocity and turbulence measurements in high-speed three-stream nozzles. Time-resolved flow imaging using a photomultiplier tube array was applied in the Nozzle Acoustic Test Rig at NASAs Aero-Acoustic Propulsion Lab to measure 250 kHz repetition laser scattering signals arising from seeding particles at 32 points in high-speed flow. Particle image velocimetry measurements previously reported by NASA provided mean velocity and turbulence intensity. Results for convection velocity of the particle concentration field were obtained from the time-resolved data for three-stream nozzle configurations using a cross-correlation approach. The three-stream cases included an axisymmetric and an asymmetric, offset nozzle configuration. For the axisymmetric case, areas of high convection velocity and turbulence intensity were found to occur 4–6 area-equivalent nozzle diameters downstream from the nozzle exit. Comparison of convection velocity between the axisymmetric and offset cases shows this same region as having the greatest reduction in convection velocity due to the offset, up to 20% reduction for the offset case compared to the axisymmetric case. These findings suggest that this region along the centerline near the end of the potential core is an important area for noise generation with jets and contributes to the noise reductions seen from three-stream offset nozzles.
Blocks of cyclotomic Hecke algebras and Khovanov-Lauda algebras

We construct an explicit isomorphism between blocks of cyclotomic Hecke algebras and (sign-modified) cyclotomic Khovanov-Lauda algebras in type A. These isomorphisms connect the categorification conjecture of Khovanov and Lauda to Ariki’s categorification theorem. The Khovanov-Lauda algebras are naturally graded, which allows us to exhibit a non-trivial ℤ-grading on blocks of cyclotomic Hecke algebras, including symmetric groups in positive characteristic.
Little String Origin of Surface Defects

We derive a large class of codimension-two defects of 4d $$ \mathcal{N}=4 $$ Super Yang-Mills (SYM) theory from the (2, 0) little string. The origin of the little string is type IIB theory compactified on an ADE singularity. The defects are D-branes wrapping the 2-cycles of the singularity. We use this construction to make contact with the description of SYM defects due to Gukov and Witten [1]. Furthermore, we provide a geometric perspective on the nilpotent orbit classification of codimension-two defects, and the connection to ADE-type Toda CFT. The only data needed to specify the defects is a set of weights of the algebra obeying certain constraints, which we give explicitly. We highlight the differences between the defect classification in the little string theory and its (2, 0) CFT limit.
On theories with light-like noncommutativity

We show that field theories with light-like noncommutativity, that is with θ0i = -θ1i, are unitary quantum theories, and that they can be obtained as decoupled field theory limits of string theory with D-branes in a background NS-NS B-field. For general noncommutativity parameters, we show that non-commutative field theories which are unitary can be obtained as decoupled field theory limits of string theory, while those that are not unitary cannot be obtained from string theory because massive open strings do not decouple. We study the different theories with light-like noncommutativity which arise from type-II D-branes. The decoupling limit of the D4-brane seems to lead to a non-commutative field theory deformation of the (2,0) SCFT of M5-branes, while the D5-brane case leads to a non-commutative variation of "little string theories". We discuss the DLCQ description of these theories.
How should spin-weighted spherical functions be defined?

Spin-weighted spherical functions provide a useful tool for analyzing tensor-valued functions on the sphere. A tensor field can be decomposed into complex-valued functions by taking contractions with tangent vectors on the sphere and the normal to the sphere. These component functions are usually presented as functions on the sphere itself, but this requires an implicit choice of distinguished tangent vectors with which to contract. Thus, we may more accurately say that spin-weighted spherical functions are functions of both a point on the sphere and a choice of frame in the tangent space at that point. The distinction becomes extremely important when transforming the coordinates in which these functions are expressed, because the implicit choice of frame will also transform. Here, it is proposed that spin-weighted spherical functions should be treated as functions on the spin or rotation groups, which simultaneously tracks the point on the sphere and the choice of tangent frame by rotating elements of an...
Effective and exact holographies from symmetries and dualities

Abstract The theoretical basis of the phenomenon of effective and exact dimensional reduction, or holographic correspondence, is investigated in a wide variety of physical systems. We first derive general inequalities linking quantum systems of different spatial (or spatio-temporal) dimensionality, thus establishing bounds on arbitrary correlation functions. These bounds enforce an effective dimensional reduction and become most potent in the presence of certain symmetries. Exact dimensional reduction can stem from a duality that (i) follows from properties of the local density of states, and/or (ii) from properties of Hamiltonian-dependent algebras of interactions. Dualities of the first type (i) are illustrated with large- n vector theories whose local density of states may remain invariant under transformations that change the dimension. We argue that a broad class of examples of dimensional reduction may be understood in terms of the functional dependence of observables on the local density of states. Dualities of the second type (ii) are obtained via bond algebras, a recently developed algebraic tool. We apply this technique to systems displaying topological quantum order, and also discuss the implications of dimensional reduction for the storage of quantum information.
Scattering of entangled two-photon states

We consider the scattering of entangled two-photon states from collections of small particles. We also study the related Mie problem of scattering from a sphere. In both cases, we calculate the entropy of entanglement and investigate the influence of the entanglement of the incident field on the entanglement of the scattered field.
Quantum Multicriticality near the Dirac-Semimetal to Band-Insulator Critical Point in Two Dimensions: A Controlled Ascent from One Dimension

A new theoretical analysis of anistropic semimetals could lead to a better understanding of how conflicting behaviors such as superconductivity and antiferromagnetism arise in condensed-matter systems.
TYPE I PLANET MIGRATION IN A MAGNETIZED DISK. I. EFFECT OF LARGE-SCALE VERTICAL AND AZIMUTHAL FIELD COMPONENTS

We study the effects of a large-scale, ordered magnetic field in protoplanetary disks on Type I planet migration using a combination of numerical simulations in 2D and 3D and a linear perturbation analysis. Steady-state models of such disks require the inclusion of magnetic diffusivity. To make progress using ideal MHD, we focus on simplified field configurations, involving purely vertical ($B_z$) and azimuthal ($B_\varphi$) field components and a combination of the two. For each of the models we calculate the locations of the relevant resonances and of the turning points, which delineate the propagation regions of the MHD waves that transport angular momentum from the planet to the disk. We use both numerical and semianalytic methods to evaluate the cumulative back torque acting on the planet, and explore the effect of spatial gradients in the disk's physical variables on the results. We conclude that, under realistic (3D) circumstances, a large-scale magnetic field can slow down the inward migration that characterizes the underlying unmagnetized disk --- by up to a factor of $\sim 2$ when the magnetic pressure approaches the thermal pressure --- but it cannot reverse it. A previous inference that a pure-$B_\phi$ field whose amplitude decreases fast enough with radius leads to outward migration applies only in 2D. In fact, we find that, in 3D, a pure-$B_\phi$ disk undergoes a rapid transition to turbulence on account of a magnetorotational instability that is triggered by the planet-induced appearance of a weak $B_z$ component.