cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Dynamical AdS strings across horizons
Creators: name: Ishii, Takaaki
name: Murata, Keiju
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We examine the nonlinear classical dynamics of a fundamental string in anti-de Sitter spacetime. The string is dual to the flux tube between an external quark-antiquark pair in $\mathcal{N}=4$ super Yang-Mills theory. We perturb the string by shaking the endpoints and compute its time evolution numerically. We find that with sufficiently strong perturbations the string continues extending and plunges into the Poincaré horizon. In the evolution, effective horizons are also dynamically created on the string worldsheet. The quark and antiquark are thus causally disconnected, and the string transitions to two straight strings. The forces acting on the endpoints vanish with a power law whose slope depends on the perturbations. The condition for this transition to occur is that energy injection exceeds the static energy between the quark-antiquark pair.
description: 29 pages, 15 figures
Analytic solution to swing equations in power grids with ZIP Load Models
Creators: name: Oh, HyungSeon
Publisher: name: arXiv
Year: 2023
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: Objective: This research pioneers a novel approach to obtain a closed-form analytic solution to the nonlinear second order differential swing equation that models power system dynamics. The distinctive element of this study is the integration of a generalized load model known as a ZIP load model (constant impedance Z, constant current I, and constant power P loads).
A nonlinear model for rotationally constrained convection with Ekman pumping
Creators: name: Julien, Keith
name: Aurnou, Jonathan M.
name: Calkins, Michael A.
name: Knobloch, Edgar
name: Marti, Philippe
name: Stellmach, Stephan
name: Vasil, Geoffrey M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: It is a well established result of linear theory that the influence of differing mechanical boundary conditions, i.e., stress-free or no-slip, on the primary instability in rotating convection becomes asymptotically small in the limit of rapid rotation. This is accounted for by the diminishing impact of the viscous stresses exerted within Ekman boundary layers and the associated vertical momentum transport by Ekman pumping. By contrast, in the nonlinear regime recent experiments and supporting simulations are now providing evidence that the efficiency of heat transport remains strongly influenced by Ekman pumping in the rapidly rotating limit. In this paper, a reduced model is developed for the case of low Rossby number convection in a plane layer geometry with no-slip upper and lower boundaries held at fixed temperatures. A complete description of the dynamics requires the existence of three distinct regions within the fluid layer: a geostrophically balanced interior where fluid motions are predominately aligned with the axis of rotation, Ekman boundary layers immediately adjacent to the bounding plates, and thermal wind layers driven by Ekman pumping in between. The reduced model uses a classical Ekman pumping parameterization to alleviate the need for spatially resolving the Ekman boundary layers. Results are presented for both linear stability theory and a special class of nonlinear solutions described by a single horizontal spatial wavenumber. It is shown that Ekman pumping allows for significant enhancement in the heat transport relative to that observed in simulations with stress-free boundaries. Without the intermediate thermal wind layer the nonlinear feedback from Ekman pumping would be able to generate a heat transport that diverges to infinity. This layer arrests this blowup resulting in finite heat transport at a significantly enhanced value.
description: 38 pages, 14 figures
Antiferro skyrmion crystal phases in a synthetic bilayer antiferromagnet under an in-plane magnetic field
Creators: name: Hayami, Satoru
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We theoretically propose a generation of an antiferro skyrmion crystal (AF-SkX) in a synthetic bilayer antiferromagnetic system under an external magnetic field. By performing the simulated annealing for a spin model on a centrosymmetric bilayer triangular lattice, we find that the interplay among the layer-dependent Dzyaloshinskii-Moriya interaction, the easy-plane single-ion anisotropy, the interlayer exchange interaction, and the in-plane magnetic field leads to instability toward the AF-SkX. The obtained AF-SkX consists of the skyrmion layer and anti-skyrmion layer with opposite skyrmion numbers, which results in no skyrmion number as well as spin scalar chirality in the whole system. We also show that a ferri-type skyrmion crystal, where one of the layers has the skyrmion number of one and the other does not, appears when the magnitude of the magnetic field is varied. Our results provide a guideline to experimentally search for the AF-SkX in bulk and layered materials.
description: 11 pages, 8 figures, accepted for publication in JPSJ
Long-term evolution of Cyclotron Line energy in an eclipsing pulsar 4U 1538-522
Creators: name: Tamang, Ruchi
name: Ghising, Manoj
name: Tobrej, Mohammed
name: Rai, Binay
name: Paul, Bikash Chandra
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present the timing and spectral analysis of the HMXB source 4U 1538-522 using NuSTAR observations. One of the observations partially covers the X-ray eclipse of the source along with eclipse ingress. The source is found to spin down at the rate of 0.163 $\pm$ 0.002 s $\text{yr}^{-1}$ between $\sim$ (54973-58603) MJD. It is evident that at time $\sim$ 58620 MJD, a torque reversal occurred, thereafter the source exhibited a spin-up trend at the rate - (0.305 $\pm$ 0.018) s $\text{yr}^{-1}$ until 59275 MJD. A recent NuSTAR observation finds the pulse period of the source: (526.2341 $\pm$ 0.0041) s. The pulse profile exhibits a transition from double-peaked to single-peaked nature above $\sim$ 30 keV. We analyzed the overall trend of the temporal evolution of fundamental Cyclotron Resonance Scattering Feature (CRSF), $\text{E}_\text{cyc}$, incorporating recent NuSTAR measurements. Initially, during the time span $\sim$ (50452.16-55270.8) MJD, the cyclotron line energy is found to increase at a rate of 0.11 $\pm$ 0.03 keV $\text{yr}^{-1}$ which is further followed by a decrease at a rate - 0.14 $\pm$ 0.01 keV $\text{yr}^{-1}$ between (55270.8-59267) MJD. The combined measurements in the time span (50452.16-59267) MJD reveal that the cyclotron line energy is increasing linearly at a rate of 0.08 $\pm$ 0.02 keV $\text{yr}^{-1}$.
description: Accepted for publication in MNRAS, 11 pages, 12 figures
Constraints on the non-minimally coupled Witten-O'Raifeartaigh inflation
Creators: name: Santos, F. B. M. dos
name: Silva, R.
name: Alcaniz, J. S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We investigate the impact of a non-minimal coupling of the scalar field with gravity in inflationary models, where a small coupling is allowed. As a concrete example, we consider the Witten-O'Raifeartaigh model, where, in line with other models, the presence of a coupling strength $ξ$ can recover concordance of the inflationary parameters with cosmic microwave background (CMB) constraints, provided by the Planck collaboration. We go beyond the slow-roll regime and investigate the impact in the description of CMB anisotropies by performing a statistical analysis of the model with the most recent Planck + Baryon Acoustic Oscillations (BAO) data to seek for any indication of a non-zero coupling by data within the model. We find that not only the presence of a non-minimal coupling is seen, but the model has a slight statistical preference when compared with the standard $Λ$CDM one. We also discuss the results on the minimally-coupled model, which in general, favours the simple setting where the associated mass scale is equal to the reduced Planck mass $M_p$ while being, in general, disfavored concerning the standard model.
description: 12 pages, 5 figures, 3 tables
Dissociative Recombination of Rotationally Cold OH$^+$ and Its Implications for the Cosmic Ray Ionization Rate in Diffuse Clouds
Creators: name: Kálosi, Ábel
name: Gamer, Lisa
name: Grieser, Manfred
name: von Hahn, Robert
name: Isberner, Leonard W.
name: Jäger, Julia I.
name: Kreckel, Holger
name: Neufeld, David A.
name: Paul, Daniel
name: Savin, Daniel W.
name: Schippers, Stefan
name: Schmidt, Viviane C.
name: Wolf, Andreas
name: Wolfire, Mark G.
name: Novotný, Oldřich
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Observations of OH$^+$ are used to infer the interstellar cosmic ray ionization rate in diffuse atomic clouds, thereby constraining the propagation of cosmic rays through and the shielding by interstellar clouds, as well as the low energy cosmic ray spectrum. In regions where the H$_2$ to H number density ratio is low, dissociative recombination (DR) is the dominant destruction process for OH$^+$ and the DR rate coefficient is important for predicting the OH$^+$ abundance and inferring the cosmic ray ionization rate. We have experimentally studied DR of electronically and vibrationally relaxed OH$^+$ in its lowest rotational levels, using an electron--ion merged-beams setup at the Cryogenic Storage Ring. From these measurements, we have derived a kinetic temperature rate coefficient applicable to diffuse cloud chemical models, i.e., for OH$^+$ in its electronic, vibrational, and rotational ground level. At typical diffuse cloud temperatures, our kinetic temperature rate coefficient is a factor of $\sim 5$ times larger than the previous experimentally derived value and a factor of $\sim 33$ times larger than the value calculated by theory. Our combined experimental and modelling results point to a significant increase for the cosmic ray ionization rate inferred from observations of OH$^+$ and H$_2$O$^+$, corresponding to a geometric mean of $(6.6 \pm 1.0) \times 10^{-16}\,\mathrm{s}^{-1}$, which is more than a factor of two larger than the previously inferred values of the cosmic ray ionization rate in diffuse atomic clouds. Combined with observations of diffuse and dense molecular clouds, these findings indicate a greater degree of cosmic ray shielding in interstellar clouds than has been previously inferred.
description: Main paper: PDFLaTeX with 10 pages, 4 figures. Appendix starting on page 11: PDFLaTeX with 10 pages, 3 figures, 2 tables. This is the Accepted Manuscript version of an article accepted for publication in The Astrophysical Journal Letters. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it
Oblique rings from migrating exomoons: A possible origin for long-period exoplanets with enlarged radii
Creators: name: Saillenfest, Melaine
name: Sulis, Sophia
name: Charpentier, Paul
name: Santerne, Alexandre
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Context. The extremely low density of several long-period exoplanets in mature systems is still unexplained -- with HIP 41378 f being archetypical of this category. It has been proposed that such planets could actually have normal densities but be surrounded by a ring observed approximately face on, mimicking the transit depth of a puffy planet. This would imply that the equator of the planet is nearly perpendicular to its orbit plane, which is at odds with the formation process of gas giants. Yet, in the context of the Solar System planets, it has been shown that after gigayears of evolution, the tidal migration of a moon can naturally lead to a very tilted planet with a ring. Aims. As exomoons are expected to be ubiquitous around giant exoplanets, this mechanism may be responsible for the anomalous radii of some observed exoplanets. In preparation for the future discoveries of the PLATO mission, we present a simple method for checking the plausibility of this mechanism for a given exoplanet. Methods. Analytical formulas give the probability density function of the relevant precession harmonics of the planet. For each harmonic, simple criteria set the moon mass and other properties required for the mechanism to operate. Results. We applied this methodology to HIP 41378 f, and we show that in order to reproduce the observed configuration, a hypothetical former moon should have had a moon-to-planet mass ratio of a few times 1e-4 (i.e. roughly the mass of our Moon) and have migrated over a distance of a few planet's radii on a gigayear timescale. These orders of magnitude match the properties of moons expected to exist around gaseous exoplanets. Conclusions. We conclude that the migration of a former moon is a viable formation pathway for the proposed ring and tilt of HIP 41378 f. This example strengthens the ring hypothesis and motivates its application to other targets.
description: Accepted for publication in Astronomy and Astrophysics
An Earth-grazing fireball from the Daytime $ζ$-Perseid shower observed over Spain on 10 June 2012
Creators: name: Madiedo, José M.
name: Espartero, Francisco
name: Castro-Tirado, Alberto J.
name: Pastor, Sensi
name: Reyes, José A. de los
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: On 10 June 2012, an Earth-grazer meteor which lasted over 17 s with an absolute magnitude of -4.0 $\pm$ 0.5 was observed over Spain. This work focuses on the analysis of this rare event which is, to our knowledge, the faintest Earth-grazing meteor reported in the scientific literature, but also the first one belonging to a meteor shower. Thus, the orbital parameters show that the parent meteoroid belonged to the Daytime $ζ$-Perseid meteoroid stream. According to our calculations, the meteor was produced by a meteoroid with an initial mass ranging between 115 and 1.5 kg. During its encounter with Earth, the particle travelled about 510 km in the atmosphere. Around 260 g were destroyed in the atmosphere during the luminous phase of the event as a consequence of the ablation process. The modified orbit of the remaining material, which left our planet with a fusion crust, is also calculated.
description: Accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS) on 2016 April 28
LAMOST J2043+3413 -- a Fast Disk Precession SW Sextans Candidate in Period Gap
Creators: name: Li, Xin
name: Wang, Xiaofeng
name: Liu, Jiren
name: Guo, Jincheng
name: Zhang, Ziping
name: Sun, Yongkang
name: Song, Xuan
name: Liu, Cheng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present follow-up photometric observations and time-series analysis of a nova-like, SW Sextans-type, cataclysmic variable (CV) candidate, LAMOST J204305.95+341340.6 (here after J2043+3413), with Gaia G-band magnitude of 15.30 and a distance of 990 pc, which was identified from the LAMOST spectrum. The photometric data were collected with the Tsinghua-NAOC 0.8-m telescope (TNT), TESS, ZTF, and ASAS-SN. The TESS light curve reveals the presence of two prominent periods of 2.587(8) hours and 1.09(5) days, corresponding to the orbital and superorbital (precession) period, respectively. The TNT data obtained in 2020 shows a possible quasi-periodic oscillation of 1426 seconds. The precession period is about three times shorter than that of CVs with similar orbital periods, indicating an unusually fast precessing accretion disk. The ZTF data is found to show a sudden decline of $\sim0.4$ mag on MJD 58979. From the intermittent behavior of the eclipse, we deduce that J2043+3413 is an intermediate inclination system of CV, similar to V795 Her, which is also situated in the period gap.
description: 10 pages, 9 figures
Testing black hole neutrino-dominated accretion discs for long-duration gamma-ray bursts
Creators: name: Song, Cui-Ying
name: Liu, Tong
name: Gu, Wei-Min
name: Tian, Jian-Xiang
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Long-duration gamma-ray bursts (LGRBs) are generally considered to originate from the massive collapsars. It is believed that the central engine of gamma-ray bursts (GRBs) is a neutrino-dominated accretion flow (NDAF) around a rotating stellar-mass black hole (BH). The neutrino annihilation above the NDAF is a feasible mechanism to power GRB. In this work, we analyse the distributions of the isotropic gamma-ray radiated energy and jet kinetic energy of 48 LGRBs. According to the NDAF and fireball models, we estimate the mean accreted masses of LGRBs in our sample to investigate whether the NDAFs can power LGRBs with the reasonable BH parameters and conversion efficiency of neutrino annihilation. The results indicate that most of the values of the accreted masses are less than $5~M_\odot$ for the extreme Kerr BHs and high conversion efficiency. It suggests that the NDAFs may be suitable for most of LGRBs except for some extremely high energy sources.
description: 6 pages, 1 figure, accepted for publication in MNRAS
Direct Evidence for Suppression of the Kondo Effect due to Pure Spin Current
Creators: name: Hamaya, K.
name: Kurokawa, T.
name: Oki, S.
name: Yamada, S.
name: Kanashima, T.
name: Taniyama, T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study the effect of a pure spin current on the Kondo singlet in a diluted magnetic alloy using non-local lateral spin valve structures with highly spin polarized Co2FeSi electrodes. Temperature dependence of the non-local spin signals shows a sharp reduction with decreasing temperature, followed by a plateau corresponding to the low temperature Fermi liquid regime below the Kondo temperature (TK). The spin diffusion length of the Kondo alloy is found to increase with the evolution of spin accumulation. The results are in agreement with the intuitive description that the Kondo singlet cannot survive any more in sufficiently large spin accumulation even below TK.
description: 5 pages, 4 figures
I See Dead People: Gray-Box Adversarial Attack on Image-To-Text Models
Creators: name: Lapid, Raz
name: Sipper, Moshe
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: Modern image-to-text systems typically adopt the encoder-decoder framework, which comprises two main components: an image encoder, responsible for extracting image features, and a transformer-based decoder, used for generating captions. Taking inspiration from the analysis of neural networks' robustness against adversarial perturbations, we propose a novel gray-box algorithm for creating adversarial examples in image-to-text models. Unlike image classification tasks that have a finite set of class labels, finding visually similar adversarial examples in an image-to-text task poses greater challenges because the captioning system allows for a virtually infinite space of possible captions. In this paper, we present a gray-box adversarial attack on image-to-text, both untargeted and targeted. We formulate the process of discovering adversarial perturbations as an optimization problem that uses only the image-encoder component, meaning the proposed attack is language-model agnostic. Through experiments conducted on the ViT-GPT2 model, which is the most-used image-to-text model in Hugging Face, and the Flickr30k dataset, we demonstrate that our proposed attack successfully generates visually similar adversarial examples, both with untargeted and targeted captions. Notably, our attack operates in a gray-box manner, requiring no knowledge about the decoder module. We also show that our attacks fool the popular open-source platform Hugging Face.
A fully discrete BEM-FEM scheme for transient acoustic waves
Creators: name: Hassell, Matthew E.
name: Sayas, Francisco-Javier
Publisher: name: arXiv
Year: 2016
Subjects: subject: Numerical Analysis (math.NA)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 65R20, 65M38

description: We study a symmetric BEM-FEM coupling scheme for the scattering of transient acoustic waves by bounded inhomogeneous anisotropic obstacles in a homogeneous field. An incident wave in free space interacts with the obstacles and produces a combination of transmission and scattering. The transmitted part of the wave is discretized in space by finite elements while the scattered wave is reduced to two fields defined on the boundary of the obstacles and is discretized in space with boundary elements. We choose a coupling formulation that leads to a symmetric system of integro-differential equations. The retarded boundary integral equations are discretized in time by Convolution Quadrature, and the interior field is discretized in time with the trapezoidal rule. We show that the scattering problem generates a C_0 group of isometries in a Hilbert space, and use associated estimates to derive stability and convergence results. We provide numerical experiments and simulations to validate our results and demonstrate the flexibility of the method.
A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states
Creators: name: Lee, Chen-Shen
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The one-to-one relation between the winding number and the number of robust zero-energy edge states, known as bulk-boundary correspondence, is a celebrated feature of 1d systems with chiral symmetry. Although this property can be explained by the K-theory, the underlying mechanism remains elusive. Here, we demonstrate that, even without resorting to advanced mathematical techniques, one can prove this correspondence and clearly illustrate the mechanism using only Cauchy's integral and elementary algebra. Furthermore, our approach to proving bulk-boundary correspondence also provides clear insights into a kind of system that doesn't respect chiral symmetry but can have robust left or right zero-energy edge states. In such systems, one can still assign the winding number to characterize these zero-energy edge states.
description: a new section, various improvements made
Turbulence Supported Massive Star Envelopes
Creators: name: Schultz, William
name: Bildsten, Lars
name: Jiang, Yan-Fei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The outer envelopes of massive ($M\gtrsim10\,M_{\odot}$) stars exhibit large increases in opacities from forests of lines and ionization transitions (particularly from iron and helium) that trigger near-surface convection zones. One-dimensional models predict density inversions and supersonic motions that must be resolved with computationally intensive 3D radiation hydrodynamic (RHD) modeling. Only in the last decade have computational tools advanced to the point where ab initio 3D models of these turbulent envelopes can be calculated, enabling us to present five 3D RHD Athena++ models (four previously published and one new 13$M_{\odot}$ model). When convective motions are sub-sonic, we find excellent agreement between 3D and 1D velocity magnitudes, stellar structure, and photospheric quantities. However when convective velocities approach the sound speed, hydrostatic balance fails as the turbulent pressure can account for 80% of the force balance. As predicted by Henyey, we show that this additional pressure support leads to a modified temperature gradient which reduces the superadiabaticity where convection is occurring. In addition, all five models display significant overshooting from the convection in the Fe convection zone. As a result, the turbulent velocities at the surface are indicative of those in the Fe zone. There are no confined convection zones as seen in 1D models. In particular, helium convection zones seen in 1D models are significantly modified. Stochastic low frequency brightness variability is also present in the 13$M_{\odot}$ model with comparable amplitude and characteristic frequency to observed stars.
description: 8 pages, 4 figures, 1 table
On the intensity ratio variation of the Si IV 1394/1403 Å lines during solar flares
Creators: name: Yu, Hao-Cheng
name: Hong, J.
name: Ding, M. D.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Context. The Si IV lines at 1394 Å and 1403 Å form in the solar atmosphere at a temperature of $\sim10^{4.8}$ K. They are usually considered optically thin, but their opacity can be enhanced during solar flares. Traditionally, the intensity ratio of these lines are used as an indicator of the optical thickness. However, observations have shown a wavelength-dependent intensity ratio profile $r(Δλ)$ of the the 1394 Å to 1403 Å lines. Aims. We aim to study the variation of the intensity ratio profile in solar flares and the physical reasons behind it. Method. The Si IV lines and their intensity ratio profiles are calculated from the one-dimensional radiative hydrodynamics flare model with non-thermal electron heating. Result. During flares, $r(Δλ)$ is smaller than 2 at the line core but larger than 2 at the line wings. We attribute the deviation of the ratio from 2 to two effects: the resonance scattering effect and the opacity effect. Resonance scattering increases the population ratio of the upper levels of the two lines, and as a result, increases $r(Δλ)$, in all wavelengths. The opacity effect decreases $r(Δλ)$, especially at the line core where the opacity is larger. These two effects compete with each other and cause the U-shape of $r(Δλ)$.
description: 11 pages, 24 figures. Accepted for publication in Astronomy & Astrophysics
The mass formula for an exotic BTZ black hole
Creators: name: Zhang, Baocheng
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: An exotic Banados-Teitelboim-Zanelli (BTZ) black hole has an angular momentum larger than its mass in three dimension (3D), which suggests the possibility that cosmic censorship could be violated if angular momentum is extracted by the Penrose process. In this paper, we propose a mass formula for the exotic BTZ black hole and show no violation of weak cosmic censorship in the gedanken process above by understanding properly its mass formula. Unlike the other black holes, the total energy of the exotic BTZ black hole is represented by the angular momentum instead of the mass, which supports a basic point of view that the same geometry should be determined by the same energy in 3D general relativity whose equation of motion can be given either by normal 3D Einstein gravity or by exotic 3D Einstein gravity. However, only the mass of the exotic black hole is related to the thermodynamics and other forms of energy are "dumb", which is consistent with the earlier thermodynamic analysis about exotic black holes.
Tuning towards dynamic freezing using a two-rate protocol
Creators: name: Kar, Satyaki
name: Mukherjee, Bhaskar
name: Sengupta, K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study periodically driven closed quantum systems where two parameters of the system Hamiltonian are driven with frequencies $ω_1$ and $ω_2=r ω_1$. We show that such drives may be used to tune towards dynamics induced freezing where the wavefunction of the state of the system after a drive cycle at time $T= 2π/ω_1$ has almost perfect overlap with the initial state. We locate regions in the $(ω_1 ,r)$ plane where the freezing is near exact for a class of integrable and a specific non-integrable model. The integrable models that we study encompass Ising and XY models in $d=1$, Kitaev model in $d=2$, and Dirac fermions in graphene and atop a topological insulator surface whereas the non-integrable model studied involves the experimentally realized one-dimensional (1D) tilted Bose-Hubbard model in an optical lattice. In addition, we compute the relevant correlation functions of such driven systems and describe their characteristics in the region of $(ω_1,r)$ plane where the freezing is near-exact. We supplement our numerical analysis with semi-analytic results for integrable driven systems within adiabatic-impulse approximation and discuss experiments which may test our theory.
description: v1: 9 pages 9 figs
An ALMA Spectroscopic Survey of the Brightest Submillimeter Galaxies in the SCUBA-2-COSMOS Field (AS2COSPEC): Physical Properties of z=2-5 Ultra- and Hyperluminous Infrared Galaxies
Creators: name: Liao, Cheng-Lin
name: Chen, Chian-Chou
name: Wang, Wei-Hao
name: Smail, Ian
name: Ao, Yiping
name: Chapman, Scott C.
name: Dudzeviciute, Ugne
name: Castillo, Marta Frias
name: Lee, Minju M.
name: Serjeant, Stephen
name: Swinbank, A. Mark
name: Taylor, Dominic J.
name: Umehata, Hideki
name: Zhao, Yinghe
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We report physical properties of the brightest ($S_{870\,μ\rm m}=12.4$-$19.2\,$mJy) and not strongly lensed 18 870$\,μ$m selected dusty star-forming galaxies (DSFGs), also known as submillimeter galaxies (SMGs), in the COSMOS field. This sample is part of an ALMA band$\,$3 spectroscopic survey (AS2COSPEC), and spectroscopic redshifts are measured in 17 of them at $z=2$-$5$. We perform spectral energy distribution analyses and deduce a median total infrared luminosity of $L_{\rm IR}=(1.3\pm0.1)\times10^{13}\,L_{\odot}$, infrared-based star-formation rate of ${\rm SFR}_{\rm IR}=1390\pm150~M_{\odot}\,\rm yr^{-1}$, stellar mass of $M_\ast=(1.4\pm0.6)\times10^{11}\,M_\odot$, dust mass of $M_{\rm dust}=(3.7\pm0.5)\times10^9\,M_\odot$, and molecular gas mass of $M_{\rm gas}= (α_{\rm CO}/0.8)(1.2\pm0.1)\times10^{11}\,M_\odot$, suggesting that they are one of the most massive, ISM-enriched, and actively star-forming systems at $z=2$-$5$. In addition, compared to less massive and less active galaxies at similar epochs, SMGs have comparable gas fractions; however, they have much shorter depletion time, possibly caused by more active dynamical interactions. We determine a median dust emissivity index of $β=2.1\pm0.1$ for our sample, and by combining our results with those from other DSFG samples, we find no correlation of $β$ with redshift or infrared luminosity, indicating similar dust grain compositions across cosmic time for infrared luminous galaxies. We also find that AS2COSPEC SMGs have one of the highest dust-to-stellar mass ratios, with a median of $0.02\pm0.01$, significantly higher than model predictions, possibly due to too strong of a AGN feedback implemented in the model. Finally, our complete and uniform survey enables us to put constraints on the most massive end of the dust and molecular gas mass functions.
description: 25 pages, 13 figures, published in ApJ
Cage Electron-Hydroxyl Complex State as Electron Donor in Mayenite
Creators: name: Hiraishi, M.
name: Kojima, K. M.
name: Miyazaki, M.
name: Yamauchi, I.
name: Okabe, H.
name: Koda, A.
name: Kadono, R.
name: Matsuishi, S.
name: Hosono, H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: It is inferred from the chemical shift of muon spin rotation ($μ$SR) spectra that muons implanted in pristine (fully oxidized) mayenite, [Ca$_{12}$Al$_{14}$O$_{32}]^{2+}$[$\square_5$O$^{2-}$] (C12A7, with $\square$ referring to the vacant cage), are bound to O$^{2-}$ at the cage center to form OMu$^-$ (where Mu represents muonium, a muonic analog of the H atom). However, an isolated negatively charged state (Mu$^-$, an analog of H$^-$) becomes dominant when the compound approaches the state of electride [Ca$_{12}$Al$_{14}$O$_{32}]^{2+}$[$\square_4$2e$^{-}$] as a result of the reduction process. Moreover, the OMu$^-$ state in the pristine specimen exhibits depolarization of paramagnetic origin at low temperatures (below $\sim$30~K), indicating that OMu$^-$ accompanies a loosely bound electron in the cage that can be thermally activated. This suggests that interstitial muons (and hence H) forming a "cage electron-hydroxyl" complex can serve as electron donors in C12A7.
description: 5 pages, 4 figures
Status of $e^+e^-$ Higgs Factory Projects
Creators: name: List, Jenny
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: An electron-positron collider designed for precision studies of the Higgs boson, a so-called Higgs factory is the highest-priority next collider of the particle physics community. This contribution summarises the key physics goals of such a Higgs factory and reviews the status of the various proposed realisations from mature concepts to very recent ideas. The commonalities and special advantages of circular and linear approaches will be discussed, respectively, before highlighting some recent developments regarding the key technologies, the operation scenarios and sustainability aspects for future colliders.
description: 9 pages, contribution to proceedings of EPS-HEP 2023
Multi-class Graph Clustering via Approximated Effective $p$-Resistance
Creators: name: Saito, Shota
name: Herbster, Mark
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: This paper develops an approximation to the (effective) $p$-resistance and applies it to multi-class clustering. Spectral methods based on the graph Laplacian and its generalization to the graph $p$-Laplacian have been a backbone of non-euclidean clustering techniques. The advantage of the $p$-Laplacian is that the parameter $p$ induces a controllable bias on cluster structure. The drawback of $p$-Laplacian eigenvector based methods is that the third and higher eigenvectors are difficult to compute. Thus, instead, we are motivated to use the $p$-resistance induced by the $p$-Laplacian for clustering. For $p$-resistance, small $p$ biases towards clusters with high internal connectivity while large $p$ biases towards clusters of small "extent," that is a preference for smaller shortest-path distances between vertices in the cluster. However, the $p$-resistance is expensive to compute. We overcome this by developing an approximation to the $p$-resistance. We prove upper and lower bounds on this approximation and observe that it is exact when the graph is a tree. We also provide theoretical justification for the use of $p$-resistance for clustering. Finally, we provide experiments comparing our approximated $p$-resistance clustering to other $p$-Laplacian based methods.
description: Accepted to ICML2023
Aneurhynchus mese Nixon 1980
Creators: name: Notton, David G.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Diapriidae
Aneurhynchus
Aneurhynchus mese

description: Aneurhynchus mese Nixon, 1980: 23, fig. 70.
Valid name
Aneurhynchus mese Nixon, 1980.
Summary of types
Holotype ♀, BMNH number 9.816, by original designation. Paratypes 3 ♀♀.
Primary type data
Eng: Northants/ Spratton/ viii. 1975 / I. & P.Gauld; Aneurhynchus / mese Nixon / type ♀, 197.
Type locality
England, Northamptonshire, Spratton.
Remarks
The holotype is mounted on a card point, with the right antenna disarticulated.
description: Published as part of Notton, David G., 2014, A catalogue of the types of Diapriinae (Hymenoptera, Diapriidae) at the Natural History Museum, London, pp. 1-123 in European Journal of Taxonomy 75 on page 96, DOI: 10.5852/ejt.2014.75, http://zenodo.org/record/3862773
title: SPORT & EXERCISE PSYCHOLOGY PROFESSIONAL DOCTORATE PORTFOLIO
Creators: name: Walro, P
Publisher: name: Liverpool John Moores University
Year: 2022

description: This portfolio demonstrates my personal and professional development as a trainee sport and exercise psychologist during the Professional Doctorate in Sport and Exercise Psychology at Liverpool John Moores University. The portfolio provides evidence of how I meet the competencies (professional standards, consultancy, research, teaching, and dissemination) of the British Psychological Society (BPS) and Health and Care Professions Council (HCPC) for ‘Chartered’ and ‘Practitioner’ Psychologists. The selected reading highlights literature that was influential to my personal and professional development. The practice log demonstrates the hours I spent on each learning outcome. The reflective diary highlights my learning experiences and critical moments central to the development of my personal philosophy, approach to practice, and personal development. Four applied case studies are presented. These provide accounts of my approach to service delivery in applied work, teaching, and dissemination. The case studies demonstrate work across different settings: with youth academy football coaches, an injured ballet dancer, a ballet dancer experiencing an eating disorder and ethical challenges within a ballet academy, and a psychology support program in a professional dance college. The scoping review examined resilience in elite sport. A common thread of the empirical papers is elite youth academy football. The first empirical paper explores practitioner’s design and delivery of an existential psychology program. The second empirical paper explores Team Formulation. The reflective commentary brings together my training which includes what I have learned, how I developed competencies, and how it has contributed to the development of a coherent and congruent approach to practice.
JWST Peers into the Class I Protostar TMC1A: Atomic Jet and Spatially Resolved Dissociative Shock Region
Creators: name: Harsono, Daniel
name: Bjerkeli, Per
name: Ramsey, Jon
name: Pontoppidan, Klaus
name: Kristensen, Lars
name: Jørgensen, Jes
name: Calcutt, Hannah
name: Li, Zhi-Yun
name: Plunkett, Adele
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Outflows and winds launched from young stars play a crucial role in the evolution of protostars and the early stages of planet formation. However, the specific details of the mechanism behind these phenomena, including how they affect the protoplanetary disk structure, are still debated. We present {\it JWST} NIRSpec Integral Field Unit (IFU) observations of atomic and H$_2$ lines from 1 -- 5.1 $μ$m toward the low-mass protostar TMC1A. For the first time, a collimated atomic jet is detected from TMC1A in the [Fe II] line at 1.644 $μ$m along with corresponding extended H$_2$ 2.12 $μ$m emission. Towards the protostar, we detected spectrally broad H I and He I emissions with velocities up to 300 km/s that can be explained by a combination of protostellar accretion and a wide-angle wind. The 2$μ$m continuum dust emission, H I, He I, and O I all show emission from the illuminated outflow cavity wall and scattered line emission. These observations demonstrate the potential of {\it JWST} to characterize and reveal new information about the hot inner regions of nearby protostars. In this case, a previously undetected atomic wind and ionized jet in a well-known outflow.
description: Accepted for publication on ApJL, 10 pages, 6 figures including appendix
Efficient Token-Guided Image-Text Retrieval with Consistent Multimodal Contrastive Training
Creators: name: Liu, Chong
name: Zhang, Yuqi
name: Wang, Hongsong
name: Chen, Weihua
name: Wang, Fan
name: Huang, Yan
name: Shen, Yi-Dong
name: Wang, Liang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Image-text retrieval is a central problem for understanding the semantic relationship between vision and language, and serves as the basis for various visual and language tasks. Most previous works either simply learn coarse-grained representations of the overall image and text, or elaborately establish the correspondence between image regions or pixels and text words. However, the close relations between coarse- and fine-grained representations for each modality are important for image-text retrieval but almost neglected. As a result, such previous works inevitably suffer from low retrieval accuracy or heavy computational cost. In this work, we address image-text retrieval from a novel perspective by combining coarse- and fine-grained representation learning into a unified framework. This framework is consistent with human cognition, as humans simultaneously pay attention to the entire sample and regional elements to understand the semantic content. To this end, a Token-Guided Dual Transformer (TGDT) architecture which consists of two homogeneous branches for image and text modalities, respectively, is proposed for image-text retrieval. The TGDT incorporates both coarse- and fine-grained retrievals into a unified framework and beneficially leverages the advantages of both retrieval approaches. A novel training objective called Consistent Multimodal Contrastive (CMC) loss is proposed accordingly to ensure the intra- and inter-modal semantic consistencies between images and texts in the common embedding space. Equipped with a two-stage inference method based on the mixed global and local cross-modal similarity, the proposed method achieves state-of-the-art retrieval performances with extremely low inference time when compared with representative recent approaches.
description: Code is publicly available: https://github.com/LCFractal/TGDT
Anomalous increase in nematic-isotropic transition temperature in dimer molecules induced by magnetic field
Creators: name: Salili, S. M.
name: Tamba, M. G.
name: Sprunt, S. N.
name: Welch, C.
name: Mehl, G. H.
name: Jákli, A.
name: Gleeson, J. T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We have determined the nematic-isotropic transition temperature as a function of applied magnetic field in three different thermotropic liquid crystalline dimers. These molecules are comprised of two rigid calamitic moieties joined end to end by flexible spacers with odd numbers of methylene groups. They show an unprecedented magnetic field enhancement of nematic order in that the transition temperature is increased by up to 15K when subjected to 22T magnetic field. The increase is conjectured to be caused by a magnetic field-induced decrease of the average bend angle in the aliphatic spacers connecting the rigid mesogenic units of the dimers.
Millimeter Observations of the Type II SN2023ixf: Constraints on the Proximate Circumstellar Medium
Creators: name: Berger, Edo
name: Keating, Garrett K.
name: Margutti, Raffaella
name: Maeda, Keiichi
name: Alexander, Kate D.
name: Cendes, Yvette
name: Eftekhari, Tarraneh
name: Gurwell, Mark
name: Hiramatsu, Daichi
name: Ho, Anna Y. Q.
name: Laskar, Tanmoy
name: Rao, Ramprasad
name: Williams, Peter K. G.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present 1.3 mm (230 GHz) observations of the recent and nearby Type II supernova, SN2023ixf, obtained with the Submillimeter Array (SMA) at 2.6-18.6 days after explosion. The observations were obtained as part the SMA Large Program POETS (Pursuit of Extragalactic Transients with the SMA). We do not detect any emission at the location of SN2023ixf, with the deepest limits of $L_ν(230\,{\rm GHz})\lesssim 8.6\times 10^{25}$ erg s$^{-1}$ Hz$^{-1}$ at 2.7 and 7.7 days, and $L_ν(230\,{\rm GHz})\lesssim 3.4\times 10^{25}$ erg s$^{-1}$ Hz$^{-1}$ at 18.6 days. These limits are about a factor of 2 times dimmer than the mm emission from SN2011dh (IIb), about an order of magnitude dimmer compared to SN1993J (IIb) and SN2018ivc (IIL), and about 30 times dimmer than the most luminous non-relativistic SNe in the mm-band (Type IIb/Ib/Ic). Using these limits in the context of analytical models that include synchrotron self-absorption and free-free absorption we place constraints on the proximate circumstellar medium around the progenitor star, to a scale of $\sim 2\times 10^{15}$ cm, excluding the range $\dot{M}\sim {\rm few}\times 10^{-6}-10^{-2}$ M$_\odot$ yr$^{-1}$ (for a wind velocity, $v_w=115$ km s$^{-1}$, and ejecta velocity, $v_{\rm eje}\sim (1-2)\times 10^4$ km s$^{-1}$). These results are consistent with an inference of the mass loss rate based on optical spectroscopy ($\sim 2\times 10^{-2}$ M$_\odot$ yr$^{-1}$ for $v_w=115$ km s$^{-1}$), but are in tension with the inference from hard X-rays ($\sim 7\times 10^{-4}$ M$_\odot$ yr$^{-1}$ for $v_w=115$ km s$^{-1}$). This tension may be alleviated by a non-homogeneous and confined CSM, consistent with results from high-resolution optical spectroscopy.
description: Submitted
The Dark Neutral Medium is (Mostly) Molecular Hydrogen
Creators: name: Liszt, Harvey
name: Gerin, Maryvonne
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We acquired ALMA ground state absorption profiles of HCO+ and other molecules toward 33 extragalactic continuum sources seen toward the Galactic anticenter, deriving N(H2) = N(HCO+)/3x10^{-9}. We observed J=1-0 CO emission with the IRAM 30m in directions where HCO+ was newly detected. HCO+ absorption was detected in 28 of 33 new directions and CO emission along 19 of those 28. The 5 sightlines lacking detectable HCO+ have 3 times lower mean EBV and N(DNM). Binned in EBV, N(H2) and N(DNM) are strongly correlated and vary by factors of 50-100 over the observed range EBV~0.05-1 mag, while N(HI) varies by factors of only 2-3. On average N(DNM) and N(H2) are well matched, and detecting HCO+ absorption adds little/no H2 in excess of the previously inferred DNM. There are 5 cases where 2N(H2) < N(DNM)/2 indicates saturation of the HI emission. For sightlines with \WCO > 1 K-\kms the CO-H2 conversion factor N(H2)/\WCO\ = 2-3x10^{20}\pcc/K-\kms is higher than derived from studies of resolved clouds in gamma-rays. Our work sampled primarily atomic gas with a mean H2 fraction ~1/3, but the DNM is almost entirely molecular. CO fulfills its role as an H2 tracer when its emission is strong, but large-scale CO surveys are not sensitive to H2 columns associated with typical values N(DNM) = 2-6x10^{20}\pcc. Lower \XCO\ values from $γ$-ray studies arise in part from different definitions and usage. Sightlines with \WCO\ \ge 1 K-\kms\ represent 2/3 of the H2 detected in HCO+ and detecting 90% of the H2 would require detecting CO at levels \WCO\~0.2-0.3 K-\kms For full abstract see the paper
description: Accepted to Astronomy and Astrophysics (Main Journal)