Miracle-dz/UniFAR-FTUs huggingface dataset:
FOKKER-PLANCK AND LANDAU-LIFSHITZ-BLOCH EQUATIONS FOR CLASSICAL FERROMAGNETS

A macroscopic equation of motion for the magnetization of a ferromagnet at elevated temperatures should contain both transverse and longitudinal relaxation terms and interpolate between Landau-Lifshitz equation at low temperatures and the Bloch equation at high temperatures. It is shown that for the classical model where spin-bath interactions are described by stochastic Langevin fields and spin-spin interactions are treated within the mean-field approximation (MFA), such a ``Landau-Lifshitz-Bloch'' (LLB) equation can be derived exactly from the Fokker-Planck equation, if the external conditions change slowly enough. For weakly anisotropic ferromagnets within the MFA the LLB equation can be written in a macroscopic form based on the free-energy functional interpolating between the Landau free energy near T_C and the ``micromagnetic'' free energy, which neglects changes of the magnetization magnitude |{\bf M}|, at low temperatures.
I=2 pion scattering length from two-pion wave functions

We calculate the two-pion wave function in the ground state of the I=2 S-wave system and find the interaction range between two pions, which allows us to examine the validity of the necessary condition for the finite-volume method for the scattering length proposed by Luescher. We work in the quenched approximation employing a renormalization group improved gauge action for gluons and an improved Wilson action for quarks at 1/a=1.207(12) GeV on 16{sup 3}x80, 20{sup 3}x80, and 24{sup 3}x80 lattices. We conclude that the necessary condition is satisfied within the statistical errors for the lattice sizes L{>=}24 (3.92 fm) when the quark mass is in the range that corresponds to m{sub {pi}}{sup 2}=0.273-0.736 GeV{sup 2}. We obtain the scattering length with a smaller statistical error from the wave function than from the two-pion time correlator.
Destabilization of the EW vacuum in non-minimally coupled inflation

Current cosmological data favour inflationary models non-minimally coupled to gravity. In this work we study the implications of the metastability of the electroweak vacuum in this framework. We consider an inflaton field with a non-minimal coupling to Ricci curvature and a portal coupling between the Higgs field and the inflaton and find that the ratio of the two couplings is severely constrained from stability during inflation and reheating dynamics, with constraints becoming more severe for weaker non-minimal coupling as during inflation Higgs fluctuations are amplified by inflationary expansion and after inflation by parametric resonance due to an oscillating inflaton background.
Disformally coupled scalar fields and inspiralling trajectories

We show how a nearly massless scalar field conformally and disformally coupled to matter can affect the dynamics of two bodies in their inspiralling phase before merging. We discuss both the conservative dynamics, e.g., how the energy of the bound system is corrected by the conformal and disformal interactions, and the dissipative part where scalars and gravitons are emitted. The first disformal correction to the Einstein-Infeld-Hoffmann Lagrangian is obtained using both the Fokker method relying on the equations of motion and an Effective Field Theory approach using Feynman diagrams. This leads to a correction to the energy functional at the 2 post-Newotnian level for eccentric orbits, which vanishes for circular orbits up to the 7 post-Newtonian order. The dissipative power from the disformal interaction gives a correction to the monopole and quadrupole terms in the presence of a conformal coupling. Although this correction vanishes for circular orbits at leading order, this is not the case for elliptical orbits allowing us to derive a bound on the disformal coupling from the time drift of the period for the Hulse-Taylor binary pulsar, which is slightly stronger than the one from fifth force tests. We conclude that the prospect of observing disformal effects for inspiraling systems lies in the accurate monitoring of eccentric trajectories as expected for the LISA experiment.
Monogamy of Bell correlations and Tsirelson's bound

We consider three parties, A, B, and C, each performing one of two local measurements on a shared quantum state of arbitrary dimension. We characterize the trade-off between the nonlocality of the Bell correlations observed by AB and of those observed by AC. This generalizes Tsirelson's bound on the quantum value of the CHSH inequality, the latter being recovered when C is completely uncorrelated with AB. We also discuss the trade-off between Bell violations and local expectation values of observables that anticommute with the ones used in the Bell test.
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VIII. A Comparison to Cosmological Short-duration Gamma-Ray Bursts

We present a comprehensive comparison of the properties of the radio through X-ray counterpart of GW170817 and the properties of short-duration gamma-ray bursts (GRBs). For this effort, we utilize a sample of 36 short GRBs spanning a redshift range of z ≈ 0.12 – 2.6 discovered over 2004–2017. We find that the counterpart to GW170817 has an isotropic-equivalent luminosity that is ≈ 3000 times less than the median value of on-axis short GRB X-ray afterglows, and ≳104 times less than that for detected short GRB radio afterglows. Moreover, the allowed jet energies and particle densities inferred from the radio and X-ray counterparts to GW170817 and on-axis short GRB afterglows are remarkably similar, suggesting that viewing angle effects are the dominant, and perhaps only, difference in their observed radio and X-ray behavior. From comparison to previous claimed kilonovae following short GRBs, we find that the optical and near-infrared (NIR) counterpart to GW170817 is comparatively under-luminous by a factor of ≈ 3 – 5 , indicating a range of kilonova luminosities and timescales. A comparison of the optical limits following short GRBs on ≲ 1 day timescales also rules out a “blue” kilonova of comparable optical isotropic-equivalent luminosity in one previous short GRB. Finally, we investigate the host galaxy of GW170817, NGC 4993, in the context of short GRB host galaxy stellar population properties. We find that NGC 4993 is superlative in terms of its large luminosity, old stellar population age, and low star formation rate compared to previous short GRB hosts. Additional events within the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo volume will be crucial in delineating the properties of the host galaxies of neutron star–neutron star (NS–NS) mergers, and connecting them to their cosmological counterparts.
Simple analysis of the nonlinear saturation of the tearing mode

A simple nonlinear treatment of the reduced magnetohydrodynamics equations, that describes the saturation of small width magnetic island, is presented. This procedure is an extension of Rutherford’s theory. It is found that the tearing mode saturates at a finite amplitude, ws, which is proportional to the linear stability parameter, Δ′. The correct value of the proportionality coefficient between ws and Δ′ is obtained in this paper, in agreement with numerical simulations.
Electron microscopic studies of ferroelectric crystals

It is shown that a surprising variety of microstructural phenomena in ferroelectric materials are accessible by high-resolution electron microscopic techniques. Recent observations are reviewed concerning (i) domain wall widths and surface roughness in LiTaO3, KNbO3 and barium sodium niobate (BNN); (ii) microdomain textures and fluctuations at the cubic/tetragonal phase transition of BaTiO3; (iii) the commensurate superlattice structure of BNN and (iv) the hierarchy of chaotic states coexisting within the incommensurate superstructure phase of strontium barium niobate (SBN) at room temperature.
Application of Snell's law in weakly anisotropic media

Snell’s law describes the relationship between phase angles and velocities during the reflection or transmission of waves. It states that horizontal slowness with respect to an interface is preserved during reflection or transmission. Evaluation of this relationship at an interface between two isotropic media is straightforward. For anisotropic media, it is a complicated problem because phase velocity depends on the angle; in the anisotropic reflection/transmission problem, neither is known. Solving Snell’s law in the anisotropic case requires a numerical solution for a sixth-order polynomial. In addition to finding the roots, they must be assigned to the correct reflected or transmitted wave type. We show that if the anisotropy is weak, an approximate solution based on first-order perturbation theory can be obtained. This approach permits the computation of the full slowness vector and, thereby, the phase velocity and angle. In addition to replacing the need for solving the sixth-order polynomial, the re.
The UCSD HIRES/Keck I Damped Lyα Abundance Database. IV. Probing Galactic Enrichment Histories with Nitrogen

We present 14 N0 measurements from our High Resolution Echelle Spectrometer/Keck database of damped Lyα abundances. These data are combined with measurements from the recent and past literature to build a homogeneous, uniform set of observations. We examine photoionization diagnostics such as Fe++ and Ar0 in the majority of the complete sample and assess the impact of ionization corrections on N/α and α/H values derived from observed ionic column densities of N0, Si+, H0, and S+. Our final sample of 19 N/α, α/H pairs appears bimodal; the majority of systems show N/α values consistent with metal‐poor emission regions in the local universe, but a small subsample exhibits significantly lower N/α ratios. Contrary to previous studies of N/α in the damped systems, our sample shows little scatter within each subsample. We consider various scenarios to explain the presence of the low N/α sight lines and account for the apparent bimodality. We favor a model where at least some galaxies undergo an initial burst of star formation with suppressed formation of intermediate‐mass stars. We found that a power‐law initial mass function with slope 0.10 or a mass cut of ≈5–8 M⊙ would successfully reproduce the observed low‐nitrogen damped Lyα values. If the bimodal distribution is confirmed by a larger sample of measurements, this may present the first observational evidence for a top‐heavy initial mass function in some early stellar populations.
Earthquake statistics and fractal faults

We introduce a self-affine asperity model (SAM) for the seismicity that mimics the fault friction by means of two fractional Brownian profiles that slide one over the other. An earthquake occurs when there is an overlap of the two profiles representing the two fault faces and its energy is assumed proportional to the overlap surface. The SAM exhibits the Gutenberg-Richter law with an exponent \ensuremath{\beta} related to the roughness index of the profiles. Apart from being analytically treatable, the model exhibits a nontrivial clustering in the spatiotemporal distribution of epicenters that strongly resembles the experimentally observed one. A generalized and more realistic version of the model exhibits the Omori scaling for the distribution of the aftershocks. The SAM lies in a different perspective with respect to usual models for seismicity. In this case, in fact, the critical behavior is not self-organized but stems from the fractal geometry of the faults, which, in its turn, is supposed to arise as a consequence of geological processes on very long time scales with respect to the seismic dynamics. Our approach is distinguished by the explicit introduction of the fault geometry as an active element of this complex phenomenology.
Electromigration saturation in a simple interconnect tree

Electromigration-saturation experiments have been carried out on passivated “L”-shaped interconnects which had three contacts through W-filled vias at the ends and at the corners of the L’s. Currents of different magnitudes and directions were independently applied in the two limbs of the L’s. Variations in the steady-state electrical resistances were observed, and attributed to a variation in the location of the voids along the lines. Variations in the rate of approach to the steady state were also observed, and are attributed to variations in void shapes. The effects of electromigration in L-shaped interconnects were simulated using an electromigration simulator based on the one-dimensional Korhonen et al. [J. Appl. Phys. 73, 3790 (1993)] model for electromigration, modified to include the effects of junctions. It is shown that, using a single set of input parameters and information about void shapes, the simulation can be used to make accurate worst-case predictions of the evolving and the steady state.
A rigorous computational comparison of alternative solution methods for the generalized assignment problem

Statistical experimental design and analysis is a cornerstone for scientific inquiry that is rarely applied in reporting computational testing. This approach is employed to study the relative performance characteristics of the four leading algorithmic and heuristic alternatives to solve the Linear Cost Generalized Assignment Problem (LCGAP) against a newly developed heuristic, Variable-Depth Search Heuristic (VDSH). In assessing the relative effectiveness of the prominent solution methodologies and VDSH under the effects of various problem characteristics, we devise a carefully designed experimentation of state-of-the-art implementations; through a rigorous statistical analysis we identify the most efficient method(s) for commonly studied LCGAPs, and determine the effect on solution time and quality of problem class and size.
Non-local Starobinsky inflation in the light of future CMB

Analytic infinite derivative (AID) non-local quadratic curvature gravity in Weyl basis is known to be ghost free, superrenormalizable or finite and perturbatively Unitary and as such it is Ultra-Violet (UV) complete. Recently $R+R^2$ ("Starobinsky") inflation was successfully embedded in AID non-local gravity and the corresponding observables were computed. Here in this paper, we derive the form factors compatible within near de Sitter aproaximation and prove that the theory must contain a scalaron that drives inflationary expansion. Further more we consider the form factors (AID non-local operators) proposed by Tomboulis in hep-th/9702146 and compute the corresponding predictions of tensor to scalar ratio and tensor tilt $\left( n_t,\,r \right)$ where the scalar tilt remains the same as the local Starobinsky model. Anticipating future CMB probes such will be able to test non-local Starobinsky inflation we constrain the scale of non-locality to be $10^{14}\,GeV\lesssim\mathcal{M}\lesssim 5\times 10^{14}\,GeV$ and $10^{-7}\lesssim r \lesssim 0.07$ for different form factors. We found that it possible to have a blue or red tensor tilt $\left( n_t\gtrless 0 \right)$ depending on the scale of non-locality and the form factor. We also comment on Higgs inflation in non-local context.
Spectral Properties and Variability of BIS objects

Through the analysis and interpretation of newly obtained and of literature data we have clarified the nature of poorly investigated IRAS point sources classified as late type stars, belonging to the Byurakan IRAS ~Stars catalog. From medium resolution spectroscopyof 95 stars we have strongly revised 47 spectral types and newly classified 31 sources. Nine stars are of G or K types, four are N carbon stars in the Asymptotic Giant Branch, the others being M type stars. From literature and new photometric observations we have studied their variability behaviour. For the regular variables we determined distances, absolute magnitudes and mass loss rates. For the other stars we estimated the distances, ranging between 1.3 and 10~kpc with a median of 2.8~kpc from the galactic plane, indicating that BIS stars mostly belong to the halo population.
Expectations for inflationary observables: simple or natural?

We describe the general inflationary dynamics that can arise with a single, canonically coupled field where the inflaton potential is a 4-th order polynomial. This scenario yields a wide range of combinations of the empirical spectral observables, ns, r and αs. However, not all combinations are possible and next-generation cosmological experiments have the ability to rule out all inflationary scenarios based on this potential. Further, we construct inflationary priors for this potential based on physically motivated choices for its free parameters. These can be used to determine the degree of tuning associated with different combinations of ns, r and αs and will facilitate treatments of the inflationary model selection problem. Finally, we comment on the implications of these results for the naturalness of the overall inflationary paradigm. We argue that ruling out all simple, renormalizable potentials would not necessarily imply that the inflationary paradigm itself was unnatural, but that this eventuality would increase the importance of building inflationary scenarios in the context of broader paradigms of ultra-high energy physics.
An elementary treatment of the reverse sprinkler

We discuss the reverse sprinkler problem: How does a sprinkler turn when submerged and made to suck in water? We propose a solution that requires only a knowledge of mechanics and fluid dynamics at the introductory university level. We argue that as the flow of water starts, the sprinkler briefly experiences a torque that would make it turn toward the incoming water, while as the flow of water ceases it briefly experiences a torque in the opposite direction. No torque is expected when water is flowing steadily into it unless dissipative effects, such as viscosity, are considered. Dissipative effects result in a small torque that would cause the sprinkler arm to accelerate toward the steadily incoming water. Our conclusions are discussed in light of an analysis of forces, conservation of angular momentum, and the experimental results reported by others. We review the conflicting published treatments of this problem, some of which have been incorrect and many of which have introduced complications that obsc.
Observable tests of self-interacting dark matter in galaxy clusters: cosmological simulations with SIDM and baryons

We present bahamas-SIDM, the first large-volume, $(400 \, h^{-1} \mathrm{\, Mpc})^{3}$, cosmological simulations including both self-interacting dark matter (SIDM) and baryonic physics. These simulations are important for two primary reasons: (1) they include the effects of baryons on the dark matter distribution and (2) the baryon particles can be used to make mock observables that can be compared directly with observations. As is well known, SIDM haloes are systematically less dense in their centres, and rounder, than CDM haloes. Here, we find that that these changes are not reflected in the distribution of gas or stars within galaxy clusters, or in their X-ray luminosities. However, gravitational lensing observables can discriminate between DM models, and we present a menu of tests that future surveys could use to measure the SIDM interaction strength. We ray-trace our simulated galaxy clusters to produce strong lensing maps. Including baryons boosts the lensing strength of clusters that produce no critical curves in SIDM-only simulations. Comparing the Einstein radii of our simulated clusters with those observed in the CLASH survey, we find that at velocities around $1000 \mathrm{\, km \, s^{-1}}$ an SIDM cross-section of $\sigma /m \gtrsim 1 \, \mathrm{cm^2 \, g^{-1}}$ is likely incompatible with observed cluster lensing.
The SDSS Damped Lyα Survey: Data Release 3

We present the results from a damped Lyα survey of the Sloan Digital Sky Survey, Data Release 3. We have discovered over 500 new damped Lyα systems at z > 2.2, and the complete statistical sample for z > 1.6 has more than 600 damped Lyα galaxies. We measure the H I column density distribution fH i(N, X) and its zeroth and first moments (the incidence ℓDLA and gas mass density Ω of damped Lyα systems, respectively) as a function of redshift. The key results include: (1) the full SDSS DR3 fH i(N, X) distribution (z ~ 3.06) is well fit by a Γ function (or double power law) with "break" column density Nγ = 1021.5±0.1 cm-2 and "faint-end" slope α = -1.8 ± 0.1; (2) the shape of the fH i(N, X) distributions in a series of redshift bins does not show evolution; (3) the incidence and gas mass density of damped systems decrease by 35% ± 9% and 50% ± 10% during ≈1 Gyr between the redshift intervals z = [3.0, 3.5] and z = [2.2, 2.5]; and (4) the incidence and gas mass density of damped Lyα systems in the lowest SDSS redshift bin (z = 2.2) are consistent with the current values. We investigate a number of systematic errors in damped Lyα analysis and identify only one important effect: we measure 40% ± 20% higher Ω values toward a subset of brighter quasars than toward a faint subset. This effect is contrary to the bias associated with dust obscuration and suggests that gravitational lensing may be important. Comparing the results against several models of galaxy formation in ΛCDM, we find that all of the models significantly underpredict ℓDLA at z = 3, and only SPH models with significant feedback can reproduce Ω at high redshift. Based on our results for the damped Lyα systems, we argue that the Lyman limit systems contribute ≈33% of the universe's H I atoms at all redshifts z = 2-5. Furthermore, we infer that the fH i(N, X) distribution for N < 1020 cm-2 has an inflection with slope d log f/d log N > -1. We advocate a new mass density definition, the mass density of predominantly neutral gas Ω, to be contrasted with the mass density of gas associated with H I atoms. We contend the damped Lyα systems contribute >80% of Ω at all redshifts and therefore are the main reservoirs for star formation.
How to Improve Bayesian Reasoning: Comment on Gigerenzer and Hoffrage (1995)

G. Gigerenzer and U. Hoffrage (1995) claimed that Bayesian inference problems, which have been notoriously difficult for laypeople to solve using base rates, hit rates, and false-alarm rates, become computationally simpler when information is presented with frequencies based on natural sampling. They made an evolutionary argument for the improved performance. The authors of the present article show that performance can improve with either probabilities or frequencies, depending on the rareness of the events and the type of information presented. When events are rare, probabilities are more difficult to understand than frequencies (i.e., 5 out of 1,000 vs. .005.). Furthermore, when the information is presented as joint and marginal events, nested sets become more apparent. Frequencies based on natural sampling have these desirable properties. The authors agree with Gigerenzer and Hoffrage that frequencies can improve Bayesian reasoning, but they attribute that improvement to the use of mental models that involve elements of nested sets.
XMM-Newton observation of the bursting pulsar GRO J1744-28 in quiescence

The XMM-Newton X-ray observatory performed a pointed observation of the bursting pulsar GRO J1744-28 in April 2001 for about 10 ks during a program devoted to the scan of the Galactic center region. After the discovery ofthis source by BATSE in December 1995 during a very active bursting phase, it has been in quiescence since April 1997. We present here the first detection of GRO J1744-28 in its quiescent state at a position which is consistent with previous high-energy positions (but not consistent with a proposed IR counterpart). The observed luminosity of the source in quiescence is about 6 orders of magnitude weaker than the luminosity in outburst.