Miracle-dz/UniFAR-FTUs huggingface dataset:
Oblique Electromagnetic Instabilities Driven by Pickup Ion Ring-beam Distributions in the Outer Heliosheath. II. Hybrid Simulations

Hybrid simulations are carried out to study the instabilities driven by the outer heliosheath pickup ions of ring-beam velocity distributions. Following the linear instability analysis in the companion paper, the electromagnetic instabilities at various propagation directions (0° ≤ θ ≤ 180°) are studied for pickup ion ring-beam distributions of different pickup angles (0° ≤ α ≤ 90°). Previous studies of the ring-beam pickup ion distributions have been limited to the parallel- and antiparallel-propagating modes (θ = 0° and 180°). In this paper, several one-dimensional hybrid simulations are performed to investigate the most unstable modes of different propagation angles predicted by the linear instability analysis. Moreover, two-dimensional hybrid simulations are conducted to examine the simultaneous excitation of the parallel, antiparallel, and oblique unstable modes and their role in the scattering of the outer heliosheath pickup ions. Our recent one-dimensional hybrid and particle-in-cell simulations with simulation domains along the background magnetic field demonstrated that at small pickup angles, the outer heliosheath pickup ions experience an incomplete scattering limited to the hemisphere of positive parallel velocities with respect to the background magnetic field. In contrast, the present two-dimensional hybrid simulation results show that when both parallel/antiparallel and oblique unstable modes are acting together, the pickup ions can be scattered into the hemisphere of negative parallel velocities and approach a near-isotropic velocity distribution. This is in conflict with the spatial retention scenario of the energetic neutral atom ribbon observed by the Interstellar Boundary Explorer, which requires pickup ions at small pickup angles to stream away from the ribbon directions.
The CIDA Variability Survey of Orion OB1. I. The Low-Mass Population of Ori OB1a and 1b

We present results of a large-scale, multiepoch optical survey of the Orion OB1 association, carried out with the QUEST camera at the Venezuela National Astronomical Observatory. We identify for the first time the widely spread low-mass, young population in the Ori OB1a and OB1b subassociations. Candidate members were picked up by their variability in the V band and position in color-magnitude diagrams. We obtained spectra to confirm membership. In a region spanning ∼68 deg2, we found 197 new young stars; of these, 56 are located in the Ori OB1a subassociation and 141 in Ori OB1b. The spatial distribution of the low-mass young stars is spatially coincident with that of the high-mass members but suggests a much sharper edge to the association. Comparison with the spatial extent of molecular gas and extinction maps indicates that the subassociation Ori OB1b is concentrated within a ringlike structure of radius ∼2°(∼15 pc at 440 pc), centered roughly on the star ϵ Ori in the Orion belt. The ring is apparent in 13CO and corresponds to a region with an extinction AV ≥ 1. The stars exhibiting strong Hα emission, an indicator of active accretion, are found along this ring, whereas the center is populated with weak Hα-emitting stars. In contrast, Ori OB1a is located in a region devoid of gas and dust. We identify a grouping of stars within a ∼3 deg2 area located in Ori OB1a, roughly clustered around the B2 star 25 Ori. The Herbig Ae/Be star V346 Ori is also associated with this grouping, which could be an older analog of σ Ori. Using several sets of evolutionary tracks, we find an age of 7–10 Myr for Ori OB1a and of ∼4–6 Myr for Ori OB1b, consistent with previous estimates from OB stars. Indicators such as the equivalent width of Hα and near-IR excesses show that the number of accreting low-mass stars decreases sharply between Ori OB1b and Ori OB1a. These results indicate that although a substantial fraction of accreting disks remain at ages ∼5 Myr, inner disks are essentially dissipated by 10 Myr.
Fisher Metric, Geometric Entanglement and Spin Networks

Starting from recent results on the geometric formulation of quantum mechanics, we propose a new information geometric characterization of entanglement for spin network states in the context of quantum gravity. For the simple case of a single-link fixed graph (Wilson line), we detail the construction of a Riemannian Fisher metric tensor and a symplectic structure on the graph Hilbert space, showing how these encode the whole information about separability and entanglement. In particular, the Fisher metric defines an entanglement monotone which provides a notion of distance among states in the Hilbert space. In the maximally entangled gauge-invariant case, the entanglement monotone is proportional to a power of the area of the surface dual to the link thus supporting a connection between entanglement and the (simplicial) geometric properties of spin network states. We further extend such analysis to the study of nonlocal correlations between two nonadjacent regions of a generic spin network graph characterized by the bipartite unfolding of an intertwiner state. Our analysis confirms the interpretation of spin network bonds as a result of entanglement and to regard the same spin network graph as an information graph, whose connectivity encodes, both at the local and nonlocal level, the quantum correlations among its parts. This gives a further connection between entanglement and geometry.
Surface and Core Detonations in Rotating White Dwarfs

The feasibility of the double detonation mechanism—surface helium detonation followed by complete carbon detonation of the core—in a rotating white dwarf with mass ≃1 M⊙ is studied using three-dimensional hydrodynamic simulations. A rapid rigid rotation of the white dwarf was assumed, so that its initial spherical geometry is considerably distorted. Unlike spherically symmetric models, we found that when helium ignition is located far from the spinning axis, the detonation fronts converge asynchronically at the antipodes of the ignition point. Nevertheless, the detonation of the carbon core still remains as the most probable outcome. The detonation of the core gives rise to a strong explosion, matching many of the basic observational constraints of Type Ia supernovae (SNe Ia). We conclude that the double detonation mechanism also works when the white dwarf is rapidly rotating. These results provide further evidence for the viability of sub-Chandrasekhar-mass models as well as some double degenerate models (those having some helium fuel at the merging moment), making them appealing channels for the production of SN Ia events.
Thermodynamical study on universal horizons in higher 
D
-dimensional spacetime and aether waves

We investigate behaviors of the $D$-dimensional gravity coupled to a dynamical unit timelike vector, the aether, present two new kinds of exact charged solutions and study the linearized wave spectrum of this theory. We find that in the case of uncharged case, one can construct the (or a slightly modified) first law at the universal horizons for both kinds of black holes. For the second kind aether black hole and for the first kind one in the extremal higher dimensions, the charge should be severely constrained that $\bar Q\ll \bar r_0/2$. Our results show that the spin-1 and spin-2 modes are the same as those in 4-dimensional spacetime, and only the spin-0 one is different and dependant on the dimension number $n$.
Keck OSIRIS AO LIRG Analysis (KOALA): Feedback in the Nuclei of Luminous Infrared Galaxies

The role of feedback in triggering or quenching star formation and hence driving galaxy evolution can be directly studied with high-resolution integral field observations. The manifestation of feedback in shocks is particularly important to examine in galaxy mergers, where violent interactions of gas take place in the interstellar medium during the course of the galactic collision. As part of our effort to systematically study the local population of luminous infrared galaxies within the Great Observatories All-Sky LIRG Survey, we undertook the Keck OSIRIS AO LIRG Analysis observing campaign to study the gas dynamics in the inner kiloparsec regions of these systems at spatial scales of a few tens of pc. With high-resolution near-infrared adaptive optics–assisted integral field observations taken with OSIRIS on the Keck Telescopes, we employ near-infrared diagnostics such as Brγ and the rovibrationally excited H2 lines to quantify the nuclear star formation rate and identify feedback associated with shocked molecular gas seen in 21 nearby luminous infrared galaxies. Shocked molecular gas is preferentially found in the ultraluminous infrared systems but may also be triggered at a lower-luminosity, earlier merging stage. On circumnuclear scales, AGNs have a strong effect on heating the surrounding molecular gas, though their coupling is not simply driven by AGN strength but rather is complicated by orientation, dust shielding, density, and other factors. We find that nuclear star formation correlates with merger class and diminishing projected nuclear separations. These trends are largely consistent with the picture of merger-induced starbursts in the center of galaxy mergers.
Stability and stabilization of switched polynomial nonlinear systems

Abstract This paper considers the stability and stabilization of a class of switched polynomial nonlinear systems. Firstly, based on time-dependent switching control and a set of auxiliary matrices, new explicit sufficient conditions are developed to ensure asymptotical stability of the studied class of systems. Moreover, switching rule design is considered for this class of systems with state-dependent switching control. Sufficient conditions for stability and stabilization are given in polynomial matrix inequalities (PMIs), and these conditions can be verified by sum of squares technique which solves linear matrix inequality feasibility problem in essence. A numerical example is provided to illustrate the effectiveness of the proposed methods.
Two-photon Optical Frequency Reference with Active ac Stark Shift Cancellation

An optical reference based on a two-photon optical transition with ac Stark shift cancellation is proposed. The reference uses two interrogating laser fields at different frequencies. Compared to conventional optical two-photon references, the new approach offers the possibility for improved short-term stability resulting from a higher signal-to-noise and improved long-term stability due to active ac Stark shift cancellation. We demonstrate the ac Stark shift cancellation method on the $5s\,{^2S}_{1/2} \rightarrow 5d\,{^2D}_{5/2}$ two-photon transition in $^{87}$Rb.
Migrating Jupiter up to the habitable zone: Earth-like planet formation and water delivery

Several observational works have shown the existence of Jupiter-mass planets covering a wide range of semi-major axes around Sun-like stars. We aim to analyse the planetary formation processes around Sun-like stars that host a Jupiter-mass planet at intermediate distances ranging from $\sim$1 au to 2 au. Our study focusses on the formation and evolution of terrestrial-like planets and water delivery in the habitable zone (HZ) of the system. Our goal is also to analyse the long-term dynamical stability of the resulting systems. A semi-analytic model was used to define the properties of a protoplanetary disk that produces a Jupiter-mass planet around the snow line, which is located at $\sim$2.7 au for a solar-mass star. Then, it was used to describe the evolution of embryos and planetesimals during the gaseous phase up to the formation of the Jupiter-mass planet, and we used the results as the initial conditions to carry out N-body simulations of planetary accretion. Our simulations produce three different classes of planets in the HZ: 'water worlds', with masses between 2.75 $M_{\oplus}$ and 3.57 $M_{\oplus}$ and water contents of 58% and 75% by mass, terrestrial-like planets, with masses ranging from 0.58 $M_{\oplus}$ to 3.8 $M_{\oplus}$ and water contents less than 1.2% by mass, and 'dry worlds', simulations of which show no water. A relevant result suggests the efficient coexistence in the HZ of a Jupiter-mass planet and a terrestrial-like planet with a percentage of water by mass comparable to the Earth. Moreover, our study indicates that these planetary systems are dynamically stable for at least 1 Gyr. Systems with a Jupiter-mass planet located at 1.5 au - 2 au around solar-type stars are of astrobiological interest. These systems are likely to harbour terrestrial-like planets in the HZ with a wide diversity of water contents.
In-Duct Acoustic Source Reconstruction from Pressure and Velocity-Based Measurements

The question addressed in this work is the determination of the practical capability of model-based methods to reconstruct a given acoustic source distribution from either pressure-based or velocity-based measurements at field points inside a cylindrical duct. An analytical model has first been implemented for the sound field due to elementary sources in a hard-walled duct of finite length. An interpretation is proposed of in-duct multi-modal propagation in terms of wavenumber-filtering. Due to the modal characteristic impedance terms, spatial low-pass filtering is associated to pressure-based field whereas this filter factor does not appear when considering velocity-based field. The inversion of the pressure-based frequency response functions involves a reciprocal factor which amplifies the high spatial frequency and increases the numerical instability of the inversion. It is found that, under non-ideal conditions, i.e. at low frequency and beyond the near-field zone, velocity-based field measurements are more favourable than pressure-based field measurements for acoustic source reconstruction in terms of both accuracy and spatial resolution.
Where is the supercritical fluid on the phase diagram?

We discuss the fluid state of matter at high temperature and pressure. We review the existing ways in which the boundary between a liquid and a quasigas fluid above the critical point are discussed. We show that the proposed 'thermodynamic' continuation of the boiling line, the 'Widom line', exists as a line near the critical point only, but becomes a bunch of short lines at a higher temperature. We subsequently propose a new 'dynamic' line separating a liquid and a gas-like fluid. The dynamic line is related to different types of particle trajectories and different diffusion mechanisms in liquids and dense gases. The location of the line on the phase diagram is determined by the equality of the liquid relaxation time and the minimal period of transverse acoustic excitations. Crossing the line results in the disappearance of transverse waves at all frequencies, the diffusion coefficient acquiring a value close to that at the critical point, the speed of sound becoming twice the particle thermal speed, and the specific heat reaching 2. In the high-pressure limit, the temperature on the dynamic line depends on pressure in the same way as does the melting temperature. In contrast to the Widom line, the proposed dynamic line separates liquid and gas-like fluids above the critical point at arbitrarily high pressure and temperature. We propose calling the new dynamic line the 'Frenkel line'.
Accurate Calculation of Fault-Rupture Models Using the High-Order Discontinuous Galerkin Method on Tetrahedral Meshes

We present a new method for near-source ground-motion calculations due to earthquake rupture on potentially geometrically complex faults. Following the recently introduced Discontinuous Galerkin approach with local time stepping on tetrahedral meshes, we use piecewise polynomial approximations of the unknown variables inside each element and achieve the same approximation order in time and space due to the new ader time integration scheme that uses Arbitrary high-order DERivatives. We show how an external source term and its heterogeneous properties in space and time, given by a fine discretization of an extended rupture surface, can be included in much coarser tetrahedral meshes due to the subcell resolution of the high-order polynomial representation. Hereby, the rupture surface is represented very generally as a point cloud of the center locations of individual subfaults at which each polynomial test function is evaluated exactly inside an element and the space– time integration of the source term is accurately computed at each timestep. Besides the incorporation of complex source kinematics we also present the effects of model boundaries that can degrade the accuracy of seismograms due to weak artificial reflections. We propose an extended computational domain of a coarsely meshed buffer region and show that our scheme using the local timestepping completely avoids such boundary problems with only slightly increasing the computational cost. We validate the new approach against different test cases, comparing our results with analytic, quasianalytic, and a series of reference solutions. Our work shows that adding the functionality of accurately treating finite source-rupture models into the general framework of the ader-Discontinuous Galerkin approach is an important contribution to modeling realistic earthquake scenarios, allowing the efficient inclusion of heterogeneous source kinematics and complex rupture-surface geometries in near-source ground-motion simulations.
Time reversal of wideband microwaves

In this letter, time reversal is applied to wideband electromagnetic waves in a reverberant room. To that end a multiantenna time reversal mirror (TRM) has been built. A 150MHz bandwidth pulse at a central frequency of 2.45GHz is radiated by a monopolar antenna, spread in time due to reverberation, recorded at the TRM, time reversed, and retransmitted. The time-reversed wave converges back to its source and focus in both time and space. The time compression is studied versus the number of antennas in the TRM and its bandwidth. The focal spot is also measured thanks to an eight-channel receiving array.
Wave suppression by nonlinear finite-dimensional control

Korteweg-de Vries-Burgers (KdVB) and Kuramoto-Sivashinsky (KS) equations are two nonlinear partial differential equations (PDEs) which can adequately describe motion of waves in a variety of fluid flow processes. We synthesize nonlinear finite-dimensional output feedback controllers for the KdVB and KS equations that enhance convergence rate and achieve stabilization to spatially uniform steady-states, respectively. The controllers use measurements obtained by point sensors and are implemented through point control actuators. The performance of the proposed controllers is successfully tested through simulations.
Continuous-wave mode-locked optical parametric oscillator

We report a novel technique for the generation of mode-locked pulses from a continuous-wave (cw) optical parametric oscillator (OPO). The technique is based on the deployment of an electro-optic phase modulator (EOM) in combination with an antiresonant ring (ARR) interferometer internal to a cw OPO. The scheme is implemented in a doubly-resonant cw OPO based on MgO:sPPLT, configured in a standing-wave cavity and pumped at 532 nm by a cw laser. With careful adjustment of the cavity length, modulation frequency and modulation depth, under different conditions, we achieved stable train of 730 ps and 450 ps pulses at a repetition rate of 160 MHz and 80 MHz, respectively. At degeneracy, spectral broadening of ~38 nm and ~20 nm has been observed corresponding to pulses of 160 MHz and 80 MHz repetition rate, respectively. We have confirmed true mode-locked operation by verifying ~4 times enhancement in second-harmonic-generation power under mode-locked operation at both 160 MHz and 80 MHz, compared to that in cw operation, for a fixed average fundamental power.
Some examples of cyclic vectors in the Dirichlet space

We consider the Hilbert space of analytic functions in the open unit disc that have a finite Dirichlet integral. For E, a closed subset of the unit circle with logarithmic capacity zero, we construct a function in this space which is uniformly continuous, vanishes on E, and is cyclic with respect to the shift operator. For A, the open unit disk in the complex plane, let D be the space of functions f analytic on A with finite Dirichlet integral J f12 dx dy < oo. If f has a Taylor expansion
Psychological and Physiological Acoustics Session 1 pPPa : Binaural Hearing and Binaural Techniques I 1 pPPa 2 . A study of spherical harmonics interpolation for HRTF exchange

Today, there exists a growing number of publicly available HRTF datasets, with each set often proposing a unique variation on the spatial discretization measurement grid. These various grids, typically determined by the mechanical system employed, result in datasets which are not directly comparable or exploitable. To alleviate the limitation of incompatible grids and assist in the adaptation of measurements performed on one grid to another, facilitating the inter-exchange of HRTF sets, a fixed radius HRTF interpolation method is proposed. The approach is based on a decomposition of the sound field using spherical harmonics, allowing for a global spatial recomposition. A high spatial density HRTF was used as a test case for evaluating the interpolation method, and a series of measures are employed to quantitatively compare the quality of the interpolation as theoretical laws.
BE-HaPPY: bias emulator for halo power spectrum including massive neutrinos

We study the clustering properties of dark matter haloes in real- and redshift-space in cosmologies with massless and massive neutrinos through a large set of state-of-the-art N-body simulations. We provide quick and easy-to-use prescriptions for the halo bias on linear and mildly non-linear scales, both in real and redshift-space, which are valid also for massive neutrinos cosmologies. Finally we present a halo bias emulator, BE-HaPPY, calibrated on the N-body simulations, which is fast enough to be used in the standard Markov Chain Monte Carlo approach to cosmological inference. For a fiducial standard ΛCDM cosmology BE-HaPPY reproduces the simulation inputs with percent or sub-percent accuracy for the halo mass cuts it is calibrated on (M>{5×1011, 1012, 3× 1012, 1013} h-1 M⊙) on the scales of interest (linear and well into the mildly non-linear regime). The approach presented here represents a well defined route to meeting the halo-bias accuracy requirements for the analysis of next-generation large-scale structure surveys. The software BE-HaPPY can run both in emulator mode and in calibration mode, on user-supplied simulations outputs, and is made publicly available.
Scanning tunneling microscopy and spectroscopy of finite-size twisted bilayer graphene

Finite-size twisted bilayer graphene (TBG, where here the TBG is of nanoscale size) is quite unstable and will change its structure to a Bernal (or $AB$-stacking) bilayer with a much lower energy. Therefore, the lack of finite-size TBG makes its electronic properties difficult to access in experiments. In this paper, a special confined TBG is obtained in the overlaid area of two continuous misoriented graphene sheets. The width of the confined region of the TBG changes gradually from about 22 to 0 nm. By using scanning tunneling microscopy, we study carefully the structure and the electronic properties of finite-size TBG. Our results indicate that the low-energy electronic properties, including twist-induced Van Hove singularities (VHSs) and spatial modulation of the local density of states, are strongly affected by the translational symmetry breaking of the finite-size TBG. However, the electronic properties above the energy of the VHSs are almost not influenced by quantum confinement even when the width of the TBG is reduced to only a single moir\'e spot.