Miracle-dz/UniFAR-FTUs huggingface dataset:
Multicriticality, metastability, and the roton feature in Bose-Einstein condensates with three-dimensional spin-orbit coupling

We theoretically study homogeneously trapped atomic Bose-Einstein condensates where all three momentum components couple to a pseudo-spin-$1/2$ degree of freedom. Tuning the anisotropies of spin-orbit coupling and the spin-dependent interactions is shown to provide access to a rich phase diagram with a tetracritical point, first-order phase transitions, and multiple metastable phases of stripe and plane-wave character. The elementary excitation spectrum of the axial plane-wave phase features an anisotropic roton feature and can be used to probe the phase diagram. In addition to providing a versatile laboratory for studying fundamental concepts in statistical physics, the emergence of metastable phases creates new opportunities for observing false-vacuum decay and bubble nucleation in ultra-cold-atom experiments.
Cavity-enabled spin squeezing for a quantum-enhanced atomic clock

For the past decade, the stability of microwave atomic clocks has stood at the standard quantum limit, set by the projection noise inherent in measurements on ensembles of uncorrelated particles. Here, I demonstrate an atomic clock that surpasses this limit by operating with atoms in a particular type of entangled state called a “squeezed spin state. ” The generation of non-classical spin correlations in a dilute cloud of atoms is facilitated by an optical cavity, which allows for strong collective coupling of the atomic ensemble to a single mode of light. Since the light exiting the cavity is entangled with the atoms, an appropriate measurement performed on the light field can project the atomic ensemble into a squeezed spin state. I demonstrate 3.0(8) dB of spin squeezing by this method of quantum non-demolition measurement. I further introduce a new method, cavity feedback squeezing, which uses the light field circulating in the resonator to mediate an effective interaction among the atoms. The light-mediated interaction mimics the spin dynamics of the one-axis twisting Hamiltonian, under which a coherent spin state evolves deterministically into a squeezed spin state. The states prepared by cavity feedback are intrinsically squeezed by up to 10(1) dB and detectably squeezed by up to 5.6(6) dB. Applied in an atomic clock, they produce an Allan variance 4.7(5) dB below the standard quantum limit for averaging times of up to 50 s. In a detour from engineering collective spin dynamics, I present direct observations of collective motional dynamics of atoms under the influence of cavity cooling. I demonstrate cooperatively enhanced cooling of a single collective motional mode down to a mean occupation number of 2.0 (-0.3/+0.9) phonons. The cooling is quantitatively well described by a simple, analytic quantum optomechanical model. Thesis Supervisor: Vladan Vuletic Title: Lester Wolfe Associate Professor of Physics
The central star of the planetary nebula PB 8: a Wolf-Rayet-type wind of an unusual WN/WC chemical composition

A considerable fraction of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient. As a rule, these CSPNe exhibit a chemical composition of helium, carbon, and oxygen with the majority showing Wolf-Rayet-like emission line spectra. These stars are classified as CSPNe of a spectral type [WC]. We perform a spectral analysis of CSPN PB 8 with the Potsdam Wolf-Rayet (PoWR) models for expanding atmospheres. The source PB 8 displays wind-broadened emission lines from strong mass loss. Most strikingly, we find that its surface composition is hydrogen-deficient, but not carbon-rich. With mass fractions of 55% helium, 40% hydrogen, 1.3% carbon, 2% nitrogen, and 1.3% oxygen, it differs greatly from the 30–50% of carbon which are typically seen in [WC]-type central stars. The atmospheric mixture in PB 8 has an analogy in the WN/WC transition type among the massive Wolf-Rayet stars. Therefore we suggest to introduce a new spectral type [WN/WC] for CSPNe, with PB 8 as its first member. The central star of PB 8 has a relatively low temperature of T∗ = 52 kK, as expected for central stars in their early evolutionary stages. Its surrounding nebula is less than 3000 years old, i.e. relatively young. Existing calculations for the post-AGB evolution can produce hydrogen-deficient stars of the [WC] type, but do not predict the composition found in PB 8. We discuss various scenarios that might explain the origin of this unique object.
KIC 1718290: A HELIUM-RICH V1093-Her-LIKE PULSATOR ON THE BLUE HORIZONTAL BRANCH

We introduce the first g-mode pulsator found to reside on the classical blue horizontal branch. One year of Kepler observations of KIC 1718290 reveals a rich spectrum of low-amplitude modes with periods between 1 and 12 hr, most of which follow a regular spacing of 276.3 s. This mode structure strongly resembles that of the V1093 Her pulsators, with only a slight shift toward longer periods. Our spectroscopy, however, reveals KIC 1718290 to be quite distinct from the sdB stars that show V1093 Her pulsations, which all have surface gravities higher than log g = 5.1 and helium abundances depleted by at least an order of magnitude relative to the solar composition. We find that KIC 1718290 has Teff = 22,100 K, log g = 4.72, and a super-solar helium abundance (log NHe/NH = −0.45). This places it well above the extreme horizontal branch, rather on the very blue end of the classical horizontal branch, where shell hydrogen burning is present. We conclude that KIC 1718290 must have suffered extreme mass loss during its first giant stage, but not sufficient to reach the extreme horizontal branch.
Test of Emergent Gravity

In this paper we examine a small but detailed test of the emergent gravity picture with explicit solutions in gravity and gauge theory. We first derive symplectic U(1) gauge fields starting from the Eguchi-Hanson metric in four-dimensional Euclidean gravity. The result precisely reproduces the U(1) gauge fields of the Nekrasov-Schwarz instanton previously derived from the top-down approach. In order to clarify the role of noncommutative spacetime, we take the Braden-Nekrasov U(1) instanton defined in ordinary commutative spacetime and derive a corresponding gravitational metric. We show that the Kahler manifold determined by the Braden-Nekrasov instanton exhibits a spacetime singularity while the Nekrasov-Schwarz instanton gives rise to a regular geometry—the Eguchi-Hanson space. This result implies that the noncommutativity of spacetime plays an important role for the resolution of spacetime singularities in general relativity. We also discuss how the topological invariants associated with noncommutative U(1) instantons are related to those of emergent four-dimensional Riemannian manifolds according to the emergent gravity picture.
Learning Critical Regions for Robot Planning Using Convolutional Neural Networks

In this paper, we present a new approach to learning for motion planning (MP) where critical regions of an environment with low probability measure are learned from a given set of motion plans and used to improve performance on new problem instances. We show that convolutional neural networks (CNN) can be used to identify critical regions for motion planning problems. We also introduce a new sampling-based motion planner, Learn and Link . Our planner leverages critical region locations identiﬁed by our CNN to overcome the limitations of uniform sampling, while still maintaining guarantees of correctness inherent to sampling-based algorithms. We evaluate Learn and Link against planners from the Open Motion Planning Library (OMPL) using an extensive suite of experiments on challenging motion planning problems. We show that our approach requires far less planning time than existing sampling-based planners.
Systems of Quasilinear Equations and Their Applications to Gas Dynamics

Abstract : Mathematical methods of investigating one-dimensional problems in gas dynamics are presented. Systems of quasilinear equations and principal problems for hyperbolic systems are studied in detail. Equations of gas dynamics are derived and investigated; analytic solutions of gas dynamics are presented; discontinuous flows containing shock waves are studied. The fundamentals of the theory of difference schemes are set forth and a variety of numerical solution methods for gas dynamics problems employed in practical calculations are set forth. A theory of the generalized solution is outlined for systems of quasilinear equations of the hyperbolic type. The monograph contains the results of recent work on these problem areas.
Investigation of Water Hammer Overpressure in the Hydraulic Passages of Hydropower Plants Equipped with Francis Turbines

Water hammer shortens hydraulic passage lifespan and may cause sudden failure. The primary goal is to use a hierarchical approach to assess the main parameters associated with water hammer. This will help investigate their influence and assist in decision making. Analytical calculation results and a numerical model are compared against experimental data. Our investigations examine water hammer overpressure loading induced by transient regimes. We used data from experimental campaigns carried out within the Hydro-Québec fleet that cover different types of hydraulic turbines and hydraulic passage configurations as experimental dataset. Guide vane closing rate was the main parameter controlled during the overpressure experiments and a general trend was identified for overpressure. This empirical trend is compared to model estimates in order to validate the hypothesis taken into account for calculations. An in-depth understanding of the water hammer phenomenon helps to select the appropriate theoretical model and recommend the optimal operating parameters to extend lifetime and to avoid catastrophic failures. Our study case suggests that available experimental data can be used along with gradually increasing analysis complexity to identify the optimal methodology for a given configuration.
The mass–richness relation of optically selected clusters from weak gravitational lensing and abundance with Subaru HSC first-year data

Constraining the relation between the richness N and the halo mass M over a wide redshift range for optically selected clusters is a key ingredient for cluster-related science in optical surveys, including the Subaru Hyper Suprime-Cam (HSC) survey. We measure stacked weak-lensing profiles around 1747 HSC CAMIRA clusters over a redshift range of 0.1 ≤ zcl ≤ 1.0 with N ≥ 15 using the HSC first-year shear catalog covering ∼140 deg2. The exquisite depth and image quality of the HSC survey allow us to measure lensing signals around high-redshift clusters at 0.7 ≤ zcl ≤ 1.0 with a signal-to-noise ratio of 19 within the comoving radius range $0.5\lesssim R\lesssim 15\, h^{-1}\:{\rm Mpc}$. We constrain the richness–mass relations P(ln N ∣ M, z) of HSC CAMIRA clusters assuming a log-normal distribution without informative priors on model parameters, by jointly fitting to the lensing profiles and abundance measurements under both Planck and WMAP cosmological models. We show that our model gives acceptable p-values when we add redshift-dependent terms proportional to ln (1 + z) and [ln (1 + z)]2 in the mean and scatter relations of P(ln N ∣ M, z). Such terms presumably originate from the variation of photometric redshift errors as a function of redshift. We show that constraints on the mean relation 〈M ∣ N〉 are consistent between the Planck and WMAP models, whereas the scatter values σln M ∣ N for the Planck model are systematically larger than those for the WMAP model. We also show that the scatter values for the Planck model increase toward lower richness values, whereas those for the WMAP model are consistent with constant values as a function of richness. This result highlights the importance of the scatter in the mass–richness relation for cluster cosmology.
Spoof detection using x-vector and feature switching

Detecting spoofed utterances is a fundamental problem in voice-based biometrics. Spoofing can be performed either by logical accesses like speech synthesis, voice conversion or by physical accesses such as replaying the pre-recorded utterance. Inspired by the state-of-the-art x-vector based speaker verification approach, this paper proposes a deep neural network (DNN) architecture for spoof detection from both logical and physical access. A novelty of the x-vector approach vis-a-vis conventional DNN based systems is that it can handle variable length utterances during testing. Performance of the proposed x-vector systems and the baseline Gaussian mixture model (GMM) systems is analyzed on the ASV-spoof-2019 dataset. The proposed system surpasses the GMM system for physical access, whereas the GMM system detects logical access better. Compared to the GMM systems, the proposed x-vector approach gives an average relative improvement of 14.64% for physical access. When combined with the decision-level feature switching (DLFS) paradigm, the best system in the proposed approach outperforms the best baseline systems with a relative improvement of 67.48% and 40.04% for both logical and physical access in terms of minimum tandem cost detection function (min-t-DCF), respectively.
The Effects of Skin Surface Temperature Change on Capillary Blood Flow using Video-capillaroscopy

for of of in compared with nonvascularized transfers. Indications approach for each technique by the same Lack of financial data regarding procedural reimbursement trends in abdominal wall reconstruction was identified. Analysis of such trends is important to under-stand the sustainability of current reimbursement models and to ensure adequate reimbursement for reconstructive surgeries moving forward. The purpose this study to evaluate monetary trends in Medicare reimbursement rates for 30 abdominal wall reconstruction surgical procedures over a 20-year period (2000–2020). The Schedule Look-Up Tool the for was utilized for each of the 30 included current Procedural Terminology (CPT) codes, and reimbursement data were extracted. The list of CPT codes was compiled prior to data collection in order to ensure a representative and compre-hensive analysis of commonly utilized procedural codes. Monetary data were adjusted for inflation to 2020 US dol-lars utilizing changes to the United States consumer price index. The R-squared, average annual percent change and average total percentage change in reimbursement were calculated based on these adjusted trends for all included procedures. RESULTS: After for the average reimbursement for all procedures decreased by 17.8% from to The greatest mean decrease was observed for CPT code 49568 (the implantation of mesh or other prosthesis for open incisional or ventral hernia repair or mesh for closure of debridement for necrotizing soft tissue infection, The only procedure with an increased adjusted reimbursement
Maxwell boundary conditions imply non-Lindblad master equation

From the Hamiltonian connecting the inside and outside of a Fabry-P\'erot cavity, which is derived from the Maxwell boundary conditions at a mirror of the cavity, a master equation of a non-Lindblad form is derived when the cavity embeds matters, although we can transform it to the Lindblad form by performing the rotating-wave approximation to the connecting Hamiltonian. We calculate absorption spectra by these Lindblad and non-Lindblad master equations and also by the Maxwell boundary conditions in the framework of the classical electrodynamics, which we consider the most reliable approach. We found that, compared to the Lindblad master equation, the absorption spectra by the non-Lindblad one agree better with those by the Maxwell boundary conditions. Although the discrepancy is highlighted only in the ultrastrong light-matter interaction regime with a relatively large broadening, the master equation of the non-Lindblad form is preferable rather than of the Lindblad one for pursuing the consistency with the classical electrodynamics.
Recognition of Obesity and Perceptions of Weight Loss Management in Patients With Chronic Kidney Disease: A Retrospective Cross-Sectional Study

Background: Obesity is, directly and indirectly, linked to the progression of chronic kidney disease (CKD). However, nephrologists’ recognition of obesity and willingness to address and manage obesity are unknown. Objectives: The aim of this article is to investigate if obesity is recognized and documented in the clinical encounter and to examine nephrologists’ perceptions of obesity and comfort with weight loss management. Design: We conducted a 2-part study. Part I used a retrospective chart review and part II used an anonymous online survey of practicing nephrologists (n = 14) in our center. Setting: The study took place in the Multi-care Kidney Clinic (MCKC) at London Health Sciences Centre in London, Ontario, Canada. Patients: In part I, we conducted a retrospective chart review of 10 random patients with advanced CKD and obesity (body mass index [BMI] > 30 kg/m2) from each of the nephrologists between January and December 2019. Methods: In part I, charts were assessed for documentation of obesity and/or a treatment plan (lifestyle counseling, pharmacologic intervention, and specialist referral). In part II, a survey completed by the nephrologists explored their current experience and perceptions of obesity and comfort with weight loss management. Responses were ranked on a 5-point Likert scale. Results: In all, 140 patient charts were reviewed. The median age was 69 (interquartile range [IQR] = 60-77) years, estimated glomerular filtration rate (eGFR) was 17 (IQR = 12-20) ml/min/1.73 m2, weight was 99 (IQR = 90-116) kg, and BMI was 36 (IQR = 33-40) kg/m2. Obesity with a BMI was documented in 36 (26%) charts, and only 2 (1%) documented a weight loss plan, which only included non-pharmacologic strategies. There were 13 survey responses (93% response rate). All nephrologists agreed that obesity negatively affects the health of patients with CKD. Twelve (92%) reported discussing obesity with patients, but none felt that they had time to treat it. All reported discussions of obesity would evoke a negative patient response, while 5 (38%) thought patients actually want to discuss obesity. Regarding treatment, 8 (62%) nephrologists felt comfortable with non-pharmacologic treatment, but only 1 respondent was comfortable with pharmacologic treatments. Twelve (92%) nephrologists thought patients should be referred to a specialist. Limitations: There was limited generalizability as this was a single center study. The BMI may reflect hypervolemia rather than body mass. Conclusion: In our study, nephrologists rarely document and manage obesity in patients with advanced CKD, despite their perception of treatment benefits. Improved outcomes of obesity management for patients with CKD will require increased knowledge and clinical tools to efficiently address obesity with patients.
Flux-density spectral analysis for several pulsars and two newly identified gigahertz-peaked spectra pulsars

In this paper, we present results from flux-density measurements for 21 pulsars over a wide frequency range, using the Giant Metrewave Radio Telescope (GMRT) and the Effelsberg telescope. Our sample was a set of mostly newly discovered pulsars from the selection of candidates for gigahertz-peaked spectra (GPS) pulsars. Using the results of our observations along with previously published data, we identify two new GPS pulsars. One of them, PSR J1740+1000, with dispersion measure (DM) of 24 pc cm$^{−3}$, is the first GPS pulsar with such a low DM value. We also selected several strong candidates for objects with high-frequency turnover in their spectra, which require further investigation. We also revisit our source selection criteria for future searches for GPS pulsars.
Supersymmetric field theories, scattering amplitudes and the Grassmannian

In this thesis we carry out a detailed investigation of a class of four-dimensional N=1 gauge theories, known as Bipartite Field Theories (BFTs), and their utility in integrable systems and scattering amplitudes in 4-dimensional N=4 Super-Yang-Mills (SYM). We present powerful combinatorial tools for analyzing the moduli spaces of BFTs, and find an interesting connection with the matching and matroid polytopes, which play a central role in the understanding of the Grassmannian. We use the tools from BFTs to construct (0+1)-dimensional cluster integrable systems, and propose a way of obtaining (1+1)- and (2+1)-dimensional integrable field theories. Using the matching and matroid polytopes of BFTs, we analyze the singularity structure of planar and non-planar on-shell diagrams, which are central to modern developments of scattering amplitudes in N=4 SYM. In so doing, we uncover a new way of obtaining the positroid stratication of the Grassmannian. We use tools from BFTs to understand the boundary structure of the amplituhedron, a recently found geometric object whose volume calculates the integrand of scattering amplitudes in planar N=4 SYM theory. We provide the most comprehensive study of the geometry of the amplituhedron to date. We also present a detailed study of non-planar on-shell diagrams, constructing the on-shell form using two new, independent methods: a non-planar boundary measurement valid for arbitrary non-planar graphs, and a proposal for a combinatorial method to determine the on-shell form directly from the graph.
Dynamics of test particles in the general five-dimensional Myers-Perry spacetime

We present the complete set of analytical solutions of the geodesic equation in the general five-dimensional Myers-Perry spacetime in terms of the Weierstrass $\wp$-, $\zeta$- and $\sigma$-functions. We analyze the underlying polynomials in the polar and radial equations, which depend on the parameters of the metric and the conserved quantities of a test particle, and characterize the motion by their zeros. We exemplify the efficiency of the analytical method on the basis of the explicit construction of test particle orbits and by addressing observables in this spacetime.
Misfit strain relaxation by dislocations in SrRuO3/SrTiO3 (001) heteroepitaxy

Misfit relaxation by dislocations in perovskite SrRuO3/SrTiO3 (001) heterostructure with low lattice mismatch (f=0.64%) was studied. Pure edge misfit dislocations (MDs) with a Burgers vector of the a〈011〉 type were found to be the major interfacial defects responsible for the misfit relief. They were introduced by half-loops expansion from the film surface as well as by extension of pre-existing dislocations in the substrate. These 45°-MDs formed along the 〈100〉 directions in a rectangular grid pattern, preferentially at surface steps of the TiO2-terminated SrTiO3 (STO) substrate. At film thicknesses much higher than the critical film thickness (hc), however, the MD spacing was not reduced but saturated in a nearly constant value far above the equilibrium prediction (∼61.4 nm). The saturated spacing of MDs corresponds to roughly the ledge distances on the STO surface (120–150 nm). It is suggested that difficulties in the multiplication of MDs by the already-formed ones lead to the abnormally high residual.