Miracle-dz/UniFAR-FTUs huggingface dataset:
Electrical-conductivity calculation in ab initio simulations of metals:Application to liquid sodium

We describe a calculation of the electrical conductivity in ab initio simulations of liquid sodium, using the Kubo-Greenwood formula for the optical conductivity and the molecular-dynamics scheme based on finite-temperature density functional theory. The effect of different Brillouin-zone samplings and that of the finite size of the system have been extensively studied at different temperatures. Close to the melting point, even with an adequate sampling of the Brillouin zone, our results exhibit a large discrepancy between theory and experiment. This is much reduced at higher temperatures. The possible reasons for this behavior are discussed.
Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I.

We have embarked on a project, under the aegis of the Nearby Stars (NStars)/Space Interferometry Mission Preparatory Science Program, to obtain spectra, spectral types, and, where feasible, basic physical parameters for the 3600 dwarf and giant stars earlier than M0 within 40 pc of the Sun. In this paper, we report on the results of this project for the first 664 stars in the northern hemisphere. These results include precise, homogeneous spectral types, basic physical parameters (including the effective temperature, surface gravity, and overall metallicity [M/H]), and measures of the chromospheric activity of our program stars. Observed and derived data presented in this paper are also available on the project's Web site.
Analysis of a Hubble Space Telescope Search for Red Dwarfs: Limits on Baryonic Matter in the Galactic Halo

We reexamine a deep Hubble Space Telescope pencil-beam search for red dwarfs, stars just massive enough to burn hydrogen. The authors of this search (Bahcall et al.) found that red dwarfs make up less than 6% of the Galactic halo. First, we extrapolate this result to include brown dwarfs, stars not quite massive enough to burn hydrogen; we assume a 1/ℳ mass function. Then the total mass of red dwarfs and brown dwarfs is ≤18% of the halo. This result is consistent with microlensing results, assuming a popular halo model. However, using new stellar models and parallax observations of low-mass, low-metallicity stars, we obtain much tighter bounds on low-mass stars. We find the halo red dwarf density to be less than 1% of the halo, while our best estimate of this value is 0.14%-0.37%. Thus, our estimate of the halo mass density of red dwarfs drops to 16-40 times less than the result reported by Bahcall et al. in 1994. For a 1/ℳ mass function, this suggests a total density of red dwarfs and brown dwarfs of ~0.25%-0.67% of the halo, i.e., (0.9-2.5) × 109 ℳ☉ out to 50 kpc. Such a low result would conflict with microlensing estimates by the MACHO group. We suggest that either the halo mass function must rise very steeply below the hydrogen-burning limit or the microlensing results should be reinterpreted with a different halo model or mass function.
Evidence of a large-scale positive rotation–metallicity correlation in the Galactic thick disc

This study is based on high quality astrometric and spectroscopic data from the most recent releases by Gaia and APOGEE. We select $58\,882$ thin and thick disk red giants, in the Galactocentric (cylindrical) distance range $5 < R < 13$~kpc and within $|z| < 3$~kpc, for which full chemo-kinematical information is available. Radial chemical gradients, $\partial \rm{[M/H]} / \partial \rm{R}$, and rotational velocity-metallicity correlations, $\partial V_\phi / \partial \rm{[M/H]}$, are re-derived firmly uncovering that the thick disk velocity-metallicity correlation maintains its positiveness over the $8$~kpc range explored. This observational result is important as it sets experimental constraints on recent theoretical studies on the formation and evolution of the Milky Way disk and on cosmological models of Galaxy formation.
Condensational and Collisional Growth of Cloud Droplets in a Turbulent Environment

We investigate the effect of turbulence on the combined condensational and collisional growth of cloud droplets by means of high-resolution direct numerical simulations of turbulence and a superparticle approximation for droplet dynamics and collisions. The droplets are subject to turbulence as well as gravity, and their collision and coalescence efficiencies are taken to be unity. We solve the thermodynamic equations governing temperature, water vapor mixing ratio, and the resulting supersaturation fields together with the Navier–Stokes equation. We find that the droplet size distribution broadens with increasing Reynolds number and/or mean energy dissipation rate. Turbulence affects the condensational growth directly through supersaturation fluctuations, and it influences collisional growth indirectly through condensation. Our simulations show for the first time that, in the absence of the mean updraft cooling, supersaturation-fluctuation-induced broadening of droplet size distributions enhances the collisional growth. This is contrary to classical (nonturbulent) condensational growth, which leads to a growing mean droplet size, but a narrower droplet size distribution. Our findings, instead, show that condensational growth facilitates collisional growth by broadening the size distribution in the tails at an early stage of rain formation. With increasing Reynolds numbers, evaporation becomes stronger. This counteracts the broadening effect due to condensation at late stages of rain formation. Our conclusions are consistent with results of laboratory experiments and field observations, and show that supersaturation fluctuations are important for precipitation.
Recently Quenched Galaxies at z = 0.2–4.8 in the COSMOS UltraVISTA Field

We present a new analysis of the stellar mass function and morphology of recently quenched galaxies (RQGs), whose star formation has been recently quenched for some reason. The COSMOS2015 catalog was exploited to select those galaxies at 0.2 < z < 4.8, over 1.5 deg2 of the Cosmic Evolution Survey (COSMOS) UltraVISTA field. This is the first time that RQGs are consistently selected and studied in such a wide range of redshift. We find increasing number density of RQGs with time in a broad mass range at z > 1, while low-mass RQGs start to grow very rapidly at z < 1. We also demonstrate that the migration of RQGs may largely drive the evolution of the stellar mass function of passive galaxies. Moreover, we find that the morphological type distribution of RQGs are intermediate between those of star-forming and passive galaxies. These results indicate that RQGs represent a major transitional phase of galaxy evolution, in which star-forming galaxies turn into passive galaxies, accompanied by the build up of spheroidal component.
Stationary light pulses in ultra cold atomic gasses

We present a theoretical treatment of electromagnetically induced transparency and light storage using standing wave coupling fields in a medium comprised of stationary atoms, such as an ultra cold atomic gas or a solid state medium. We show that it is possible to create stationary pulses of light which have a qualitatively different behavior than in the case of a thermal gas medium, offering greater potential for quantum information processing applications.
A Pulsational Distance to ω Centauri Based on Near-Infrared Period-Luminosity Relations of RR Lyrae Stars

We present new near-infrared (J and K) magnitudes for 114 RR Lyrae stars in the globular cluster ω Centauri (NGC 5139), which we combine with data from the literature to construct a sample of 180 RR Lyrae stars with J and K mean magnitudes on a common photometric system. This is currently the largest such sample in any stellar system. We also present updated predictions for J- and K-band period-luminosity relations for both fundamental and first-overtone RR Lyrae stars, based on synthetic horizontal branch models with metal abundance ranging from Z = 0.0001 to 0.004. By adopting for the ω Cen variables with measured metal abundances an α-element enhancement of a factor of 3 (≈0.5 dex) with respect to iron, we find a true distance modulus μ0 = 13.70 ± 0.06 ± 0.06 (random and systematic errors, respectively), corresponding to a distance d = 5.5 ± 0.03 ± 0.03 kpc. Our estimate is in excellent agreement with the distance inferred for the eclipsing binary OGLEGC 17, but differ significantly from the recent distance estimates based on cluster dynamics and on high-amplitude δ Scuti stars.
Aspects of electric-magnetic dualities in maximal supergravity

This thesis is devoted to various aspects of electric-magnetic duality and its gravitational generalization, with an emphasis on the case of maximal supergravity. It is divided into three parts. In the first part, we review the the Cremmer-Julia "hidden" symmetries of maximal supergravity in various dimensions. Two new results are obtained: we prove that those symmetries appear if and only if the Chern-Simons coupling of the $D=11$ theory takes the value predicted by supersymmetry, and we obtain a manifestly $E_{7(7)}$-invariant formula for the entropy of non-extremal black holes in $D=4$, $N=8$ supergravity. The second part is motivated by supergravity gaugings. We examine through BRST methods the local deformations of non-minimally coupled scalars and abelian vector fields in four dimensions. We prove that they are all of the usual Yang-Mills type, i.e., correspond to the gauging of some rigid symmetries of the undeformed theory. We also show that other Lagragians considered in the literature, containing additional fields, do not allow for gaugings that cannot be reached starting from the usual Lagrangian. In the third part, we construct self-contained action principles for several self-dual free fields in six dimensions. These fields are motivated by two considerations: they allow for a geometric interpretation of the electric-magnetic duality symmetries of linearized gravity in four dimensions, and they also appear in the spectrum of the chiral $N=(4,0)$ and $N=(3,1)$ "exotic supergravities" in place of a metric. The free action and supersymmetry transformations for those theories are then explicitly constructed. We check that they reduce to linearized maximal supergravity in five dimensions, and also generalize previous works on linearized supergravity by other authors in which the graviton and its dual appear on the same footing at the level of the action.
Rotation Profiles of Solar-like Stars with Magnetic Fields

We investigate the rotation profile of solar-like stars with magnetic fields. A diffusion coefficient of magnetic angular momentum transport is deduced. Rotating stellar models with different mass incorporating the coefficient are computed to give the rotation profiles. The total angular momentum of a solar model with only hydrodynamic instabilities is about 13 times larger than that of the Sun at the age of the Sun, and this model can not reproduce quasi-solid rotation in the radiative region. However, the solar model with magnetic fields not only can reproduce an almost uniform rotation in the radiative region, but also a total angular momentum that is consistent with the helioseismic result at the 3 sigma level at the age of the Sun. The rotation of solar-like stars with magnetic fields is almost uniform in the radiative region, but for models of 1.2-1.5 M(circle dot), there is an obvious transition region between the convective core and the radiative region, where angular velocity has a sharp radial gradient, which is different from the rotation profile of the Sun and of massive stars with magnetic fields. The change of angular velocity in the transition region increases with increasing age and mass.
Circumstellar environment of the M-type AGB star R Doradus

Context. Our current insights into the circumstellar chemistry of asymptotic giant branch (AGB) stars are largely based on studies of carbon-rich stars and stars with high mass-loss rates. Aims. In order to expand the current molecular inventory of evolved stars we present a spectral scan of the nearby, oxygen-rich star R Dor, a star with a low mass-loss rate (~2 × 10−7 M⊙ yr−1). Methods. We carried out a spectral scan in the frequency ranges 159.0–321.5 GHz and 338.5–368.5 GHz (wavelength range 0.8–1.9 mm) using the SEPIA/Band-5 and SHeFI instruments on the APEX telescope and we compare it to previous surveys, including one of the oxygen-rich AGB star IK Tau, which has a high mass-loss rate (~5 ×10−6 M⊙ yr−1). Results. The spectrum of R Dor is dominated by emission lines of SO2 and the different isotopologues of SiO. We also detect CO, H2O, HCN, CN, PO, PN, SO, and tentatively TiO2, AlO, and NaCl. Sixteen out of approximately 320 spectral features remain unidentified. Among these is a strong but previously unknown maser at 354.2 GHz, which we suggest could pertain to H2SiO, silanone. With the exception of one, none of these unidentified lines are found in a similarly sensitive survey of IK Tau performed with the IRAM 30 m telescope. We present radiative transfer models for five isotopologues of SiO (28SiO, 29SiO, 30SiO, Si17O, Si18O), providing constraints on their fractional abundance and radial extent. We derive isotopic ratios for C, O, Si, and S and estimate that, based on our results for 17O/18O, R Dor likely had an initial mass in the range 1.3–1.6 M⊙, in agreement with earlier findings based on models of H2O line emission. From the presence of spectral features recurring in many of the measured thermal and maser emission lines we tentatively identify up to five kinematical components in the outflow of R Dor, indicating deviations from a smooth, spherical wind.
Special role of the first Matsubara frequency for superconductivity near a quantum critical point: Nonlinear gap equation below 
Tc
 and spectral properties in real frequencies

Near a quantum-critical point in a metal a strong fermion-fermion interaction, mediated by a soft boson, destroys fermionic coherence and also gives rise to superconductivity. In a class of large $N$ models, one would naively expect an incoherent (non-Fermi liquid) normal state behavior to persist down to $T=0$. However, this is not the case for quantum-critical systems described by Eliashberg theory, where non-Fermi liquid part of the self-energy $\Sigma (\omega_m)$ is large for a generic Matsubara frequency $\omega_m = \pi T(2m+1)$, but vanishes at $\omega_m = \pm \pi T$, while the pairing interaction between fermions with these two frequencies remains strong. This peculiarity gives rise to a non-zero $T_c$ even at large $N$[Y. Wang et al PRL 117, 157001 (2016)]. We consider the system behavior below $T_c$ and contrast the two cases when $\omega_m = \pm \pi T$ are either special or not. We obtain the solution of the non-linear gap equations in real frequency axis and obtain the spectral function $A(\omega)$ and the density of states $N(\omega)$. In a conventional BCS-type superconductor $A(\omega)$ and $N(\omega)$ are peaked at the gap value $\Delta (T)$, and the peak position shifts to a smaller $\omega$ as temperature increases, i.e. the gap "closes in". However when superconductivity is induced by fermions with $\omega_m = \pm \pi T$, the peak in $N(\omega)$ remains at a finite frequency even at $T =T_c-0$, the gap just "fills in". The spectral function $A(\omega)$ either shows almost the same "gap filling" behavior, or its peak position shifts to zero frequency already at a finite $\Delta$ ("emergent Fermi arc" behavior), depending on the strength of the thermal contribution. We compare our results with the data for the cuprates and argue that "gap filling" behavior holds in the antinodal region, while the "emergent Fermi arc" behavior holds in the nodal region.
Accretion Mechanisms in the Be/X-Ray Transient System A0535+26

Four EXOSAT observations are presented of the Be/X-ray transient pulsar HDE 245770/A0535+26 obtained at various phases of the 111 d period. On all occasions, a faint X-ray flux is detected from the source which corresponds to L X (1-20 keV) = 2.5 × 10 35 ergs s -1 at 2.6 kpc. Pulsations at 103.36 ± 0.08 s and 103.29 ± 0.07 s are present during two of the four observations. The detection of a weak pulsed X-ray emission sets a limit of less than 2.5 × 10 31 G cm 3 to the magnetic dipole moment of the neutron star. The UV line and flux histories extracted from the IUE data bank are not clearly correlated with the X-ray behavior while stronger evidences for a correlation may exist at optical wavelength.
The evolution of cold neutral gas and the star formation history

There is a well known disparity between the evolution the star formation rate density, {\psi}*, and the abundance of neutral hydrogen (HI), the raw material for star formation. Recently, however, we have shown that {\psi}* may be correlated with the fraction of cool atomic gas, as traced through the 21-cm absorption of HI. This is expected since star formation requires cold (T ~ 10 K) gas and so this could address the issue of why the star formation rate density does not trace the bulk atomic gas. The data are, however, limited to redshifts of z 2. The data suggest that the cold gas fraction does exhibit a decrease, although this is significantly steeper than {\psi}* at z ~ 3. This is, however, degenerate with the extents of the absorbing galaxy and the background continuum emission and upon removing these, via canonical evolution models, we find the mean spin temperature of the gas to be ~ 3000 K, compared to the ~2000 K expected from the fit at z < 2. These temperatures are consistent with the observed high neutral hydrogen column densities, which require T < 4000 K in order for the gas not to be highly ionised.
ELUCID. V. Lighting Dark Matter Halos with Galaxies

In a recent study, using the distribution of galaxies in the north galactic pole of the SDSS DR7 region enclosed in a 500 box, we carried out our ELUCID simulation (ELUCID III). Here, we light the dark matter halos and subhalos in the reconstructed region in the simulation with galaxies in the SDSS observations using a novel neighborhood abundance matching method. Before we make use of the galaxy–subhalo connections established in the ELUCID simulation to evaluate galaxy formation models, we set out to explore the reliability of such a link. For this purpose, we focus on the following few aspects of galaxies: (1) the central–subhalo luminosity and mass relations, (2) the satellite fraction of galaxies, (3) the conditional luminosity function (CLF) and conditional stellar mass function (CSMF) of galaxies, and (4) the cross-correlation functions between galaxies and dark matter particles, most of which are measured separately for all, red, and blue galaxy populations. We find that our neighborhood abundance matching method accurately reproduces the central–subhalo relations, satellite fraction, and the CLFs, CSMFs, and biases of galaxies. These features ensure that galaxy–subhalo connections thus established will be very useful in constraining galaxy formation processes. We provide some suggestions for the three levels of using the galaxy–subhalo pairs for galaxy formation constraints. The galaxy–subhalo links and the subhalo merger trees in the SDSS DR7 region extracted from our ELUCID simulation are available upon request.
Limits on the Mass and Abundance of Primordial Black Holes from Quasar Gravitational Microlensing

The idea that dark matter can be made of intermediate-mass primordial black holes (PBHs) in the 10 M⊙ ≲ M ≲ 200 M⊙ range has recently been reconsidered, particularly in the light of the detection of gravitational waves by the LIGO experiment. The existence of even a small fraction of dark matter in black holes should nevertheless result in noticeable quasar gravitational microlensing. Quasar microlensing is sensitive to any type of compact objects in the lens galaxy, to their abundance, and to their mass. We have analyzed optical and X-ray microlensing data from 24 gravitationally lensed quasars to estimate the abundance of compact objects in a very wide range of masses. We conclude that the fraction of mass in black holes or any type of compact objects is negligible outside of the 0.05 M⊙ ≲ M ≲ 0.45 M⊙ mass range and that it amounts to 20% ± 5% of the total matter, in agreement with the expected masses and abundances of the stellar component. Consequently, the existence of a significant population of intermediate-mass PBHs appears to be inconsistent with current microlensing observations. Therefore, primordial massive black holes are a very unlikely source of the gravitational radiation detected by LIGO.
Optical Observations of GRO J1655–40 in Quiescence. I. A Precise Mass for the Black Hole Primary

We report photometric and spectroscopic observations of the black hole binary GRO J1655-40 in complete quiescence. In contrast to the 1995 photometry, the light curves from 1996 are almost completely dominated by ellipsoidal modulations from the secondary star. Model fits to the light curves, which take into account the temperature profile of the accretion disk and eclipse effects, yield an inclination of i = 69. °50 ± 0. °08 and a mass ratio of Q = M1/M2 = 2.99 ± 0.08. The precision of our determinations of i and Q allow us to determine the black hole mass to an accuracy of ≈ 4% (M1 = 7.02 ± 0.22 M☉). The secondary star's mass is M2 = 2.34 ± 0.12 M☉. The position of the secondary on the Hertzsprung-Russell diagram is consistent with that of a ≈ 2.3 M☉ star that has evolved off the main sequence and is halfway to the start of the giant branch. Using the new spectra, we present an improved value of the spectroscopic period (P = 2.ͩ62157 ± 0.ͩ00015), radial velocity semiamplitude (K = 228.2 ± 2.2 km s-1), and mass function [f(M) = 3.24 ± 0.09 M☉]. Based on the new spectra of the source and spectra of several MK spectral type standards, we classify the secondary star as F3 IV-F6 IV. Evolutionary models suggest an average mass transfer rate for such a system of 2=3.4×10−9 M☉ yr-1 = 2.16 × 1017 g s-1, which is much larger than the average mass transfer rates implied in the other six transient black hole systems but is still barely below the critical mass transfer rate required for stability.
A proof of the refined Gan–Gross–Prasad conjecture for non-endoscopic Yoshida lifts

Abstract We prove a precise formula relating the Bessel period of certain automorphic forms on GSp 4 ⁢ ( 𝔸 F ) ${\mathrm{GSp}_{4}(\mathbb{A}_{F})}$ to a central L-value. This is a special case of the refined Gan–Gross–Prasad conjecture for the groups ( SO 5 , SO 2 ) ${(\mathrm{SO}_{5},\mathrm{SO}_{2})}$ as set out by Ichino–Ikeda [12] and Liu [14]. This conjecture is deep and hard to prove in full generality; in this paper we succeed in proving the conjecture for forms lifted, via automorphic induction, from GL 2 ⁢ ( 𝔸 E ) ${\mathrm{GL}_{2}(\mathbb{A}_{E})}$ where E is a quadratic extension of F. The case where E = F × F ${E=F\times F}$ has been previously dealt with by Liu [14].
A STUDY OF SOLAR PHOTOSPHERIC TEMPERATURE GRADIENT VARIATION USING LIMB DARKENING MEASUREMENTS

The variation in area of quiet magnetic network measured over the sunspot cycle should modulate the spatially averaged photospheric temperature gradient, since temperature declines with optical depth more gradually in magnetic flux tube atmospheres. Yet, limb darkening measurements show no dependence upon activity level, even at an rms precision of 0.04%. We study the sensitivity of limb darkening to changes in area filling factor using a 3D MHD model of the magnetized photosphere. The limb darkening change expected from the measured 11-year area variation lies below the level of measured limb darkening variations, for a reasonable range of magnetic flux in quiet network and internetwork regions. So the remarkably constant limb darkening observed over the solar activity cycle is not inconsistent with the measured 11-year change in area of quiet magnetic network. Our findings offer an independent constraint on photospheric temperature gradient changes reported from measurements of the solar spectral irradiance from the Spectral Irradiance Monitor, and recently, from wavelength-differential spectrophotometry using the Solar Optical Telescope aboard the HINODE spacecraft.