Miracle-dz/UniFAR-FTUs huggingface dataset:
MAGNETIC SKYRMION LATTICES IN HEAVY FERMION SUPERCONDUCTOR UPT3

Topological analysis of nearly SO(3)_{spin} symmetric Ginzburg--Landau theory, proposed for UPt$_{3}$ by Machida et al, shows that there exists a new class of solutions carrying two units of magnetic flux: the magnetic skyrmion. These solutions do not have singular core like Abrikosov vortices and at low magnetic fields they become lighter for strongly type II superconductors. Magnetic skyrmions repel each other as $1/r$ at distances much larger then the magnetic penetration depth $\lambda$, forming a relatively robust triangular lattice. The magnetic induction near $H_{c1}$ is found to increase as $(H-H_{c1})^{2}$. This behavior agrees well with experiments.
Statistics of citation networks

The out-degree distribution of citation networks is investigated. Statistical data of the number of papers cited within a paper (out-degree) for different journals in the period 1991-1999 is reported. The out-degree distribution is characterized by a maximum at intermediate out-degrees. At the left of the maximum there are strong fluctuations from journal to journal while is quite universal at the right, with two classes of journals. These two classes are associated with the existence or not of a restriction in the maximum number of pages per paper. The shape of the out-degree distribution does not change appreciable from period to period, but the average out-degree is observed to increase logarithmically with the number of published papers. These features are modeled using a recursive search model.
The Bnl Muon Anomalous Magnetic Moment Measurement

The E821 experiment at Brookhaven National Laboratory is designed to measure the muon magnetic anomaly, a_mu, to an ultimate precision of 0.4 parts per million (ppm). Because theory can predict a_mu to 0.6 ppm, and ongoing efforts aim to reduce this uncertainty, the comparison represents an important and sensitive test of new physics. At the time of this Workshop, the reported experimental result from the 1999 running period achieved a_mu = 11 659 202(14)(6)x 10^-10 (1.3 ppm) and differed from the most precise theory evaluation by 2.6 standard deviations. Considerable additional data has already been obtained in 2000 and 2001 and the analysis of this data is proceeding well. Intense theoretical activity has also taken place ranging from suggestions of the new physics which could account for the deviation to careful re-examination of the standard model contributions themselves. Recently, a re-evaluation of the pion pole contribution to the hadronic light-by-light process exposed a sign error in earlier studies used in the standard theory. With this correction incorporated, experiment and theory disagree by a modest 1.6 standard deviations.
VLBI Monitoring of the Sub-parsec-scale Jet in the Radio Galaxy 3C 66B at 22 GHz

We present measurements of the proper motion of the sub-parsec scale jet at 22 GHz in the nearby FR I galaxy 3C 66B. Observations were made using Very Long Baseline Array (VLBA) at six epochs over four years. A phase-referencing technique was used to improve the image quality of the weak and diffuse jet components. We find that the inner knots are almost stationary, although one of them was expected to be detected with an apparent speed of 0.2 mas yr−1, according to 8 GHz monitoring at the same observation epochs. Clear flux variations are not observed in the core at 22 GHz; in contrast, clear flux enhancement is observed in the core at 8 GHz. We discuss a possible explanation: if the jet has helical structure, the viewing angles of the jet at 8 and 22 GHz differ by a few degrees, if the jet direction is almost along our line of sight. Although these results may imply the existence of a two-zone jet, which has been suggested in certain radio galaxies, it cannot explain the fact that the jet at the higher frequency is slower than that at the lower frequency.
Inside the Supernova: A Powerful Convective Engine

Condensed Abstract: We present an extensive study of the inception of supernova explosions by following the evolution of the cores of two massive stars (15 Msun and 25 Msun) in two dimensions. Our calculations begin at the onset of core collapse and stop several 100 ms after the bounce, at which time successful explosions of the appropriate magnitude have been obtained. (.) Guided by our numerical results, we have developed a paradigm for the supernova explosion mechanism. We view a supernova as an open cycle thermodynamic engine in which a reservoir of low-entropy matter (the envelope) is thermally coupled and physically connected to a hot bath (the protoneutron star) by a neutrino flux, and by hydrodynamic instabilities. (.) In essence, a Carnot cycle is established in which convection allows out-of-equilibrium heat transfer mediated by neutrinos to drive low entropy matter to higher entropy and therefore extracts mechanical energy from the heat generated by gravitational collapse. We argue that supernova explosions are nearly guaranteed and self-regulated by the high efficiency of the thermodynamic engine. (.) Convection continues to accumulate energy exterior to the neutron star until a successful explosion has occurred. At this time, the envelope is expelled and therefore uncoupled from the heat source (the neutron star) and the energy input ceases. This paradigm does not invoke new or modified physics over previous treatments, but relies on compellingly straightforward thermodynamic arguments. It provides a robust and self-regulated explosion mechanism to power supernovae which is effective under a wide range of physical parameters.
On the Common Origin of Cosmic Rays across the Ankle and Diffuse Neutrinos at the Highest Energies from Low-luminosity Gamma-Ray Bursts

We demonstrate that the ultra-high-energy cosmic rays (UHECRs) produced in the nuclear cascade in the jets of low-luminosity gamma-ray bursts (LL-GRBs) can describe the UHECR spectrum and composition, and at the same time, the diffuse neutrino flux at the highest energies. The radiation density in the source simultaneously controls the neutrino production and the development of the nuclear cascade, leading to a flux of nucleons and light nuclei describing even the cosmic-ray ankle at 5 · 1018 eV. The derived source parameters are consistent with population studies, indicating a baryonic loading factor of about 10. Our results motivate the continued experimental search of LL-GRBs as a unique GRB population.
Spiral waves in accretion discs - observations

I review the observational evidence for spiral structure in the accretion discs of cataclysmic variables (CVs). Doppler tomography is ideally suited to resolve and map such co-rotating patterns and allows a straightforward comparison with theory. The dwarf nova IP Pegasi presents the best studied case, carrying two spiral arms in a wide range of emission lines throughout its outbursts. Both arms appear at the locations where tidally driven spiral waves are expected, with the arm closest to the gas stream weaker in the lines compared to the arm closest to the companion. Eclipse data indicates sub-Keplerian velocities in the outer disc. The dramatic disc structure changes in dwarf novae on timescales of days to weeks, provide unique opportunities for our understanding of angular momentum transport and the role of density waves on the structure of accretion discs. I present an extension to the Doppler tomography technique that relaxes one of the basic assumptions of tomography, and is able to map modulated emission sources. This extension allows us to ﬁt anisotropic emission from, for example, spiral shocks, the irradiated companion star and disc-stream interaction sites. side of the issue and the comparison between the observations and numerical simulations of spiral waves in discs.
A spherical harmonic approach to redshift distortion and a measurement of $\Omega_0$ from the 1.2-Jy IRAS Redshift Survey

We examine the nature of galaxy clustering in redshift space, using a method based on an expansion of the galactic density field in spherical harmonics and linear theory. Our approach provides a compact and self-consistent expression for the distortion when applied to flux-limited redshift surveys. The amplitude of the distortion is controlled by the combination of the density and bias parameters, beta = OMEGA0(0.6)/b; we exploit this fact to derive a maximum-likelihood estimator for beta. We check our formalism using N-body simulations, and demonstrate that it provides an unbiased estimate of beta when the amplitude and shape of the galaxy power spectrum are known. Application of the technique to the 1.2-Jy IRAS Redshift Survey yields beta almost-equal-to 1.0; both random errors (from counting statistics and the uncertainties in the power-spectrum normalization) and systematic errors (from the uncertainty in the shape of the power spectrum) individually contribute 20 per cent uncertainties in this estimate. This estimate of beta is comparable (both in amplitude and uncertainty) with previous measurements based on comparisons of the IRAS density field with direct measurements of peculiar velocities and analyses of the acceleration of the Local Group, but the spherical harmonic analysis has the advantage of being easy to implement and largely free of systematic errors.
INTRODUCTION TO MODIFIED GRAVITY AND GRAVITATIONAL ALTERNATIVE FOR DARK ENERGY

We review various modified gravities considered as gravitational alternative for dark energy. Specifically, we consider the versions of f(R), f(G) or f(R, G) gravity, model with non-linear gravitational coupling or string-inspired model with Gauss-Bonnet-dilaton coupling in the late universe where they lead to cosmic speed-up. It is shown that some of such theories may pass the Solar System tests. On the same time, it is demonstrated that they have quite rich cosmological structure: they may naturally describe the effective (cosmological constant, quintessence or phantom) late-time era with a possible transition from decceleration to acceleration thanks to gravitational terms which increase with scalar curvature decrease. The possibility to explain the coincidence problem as the manifestation of the universe expansion in such models is mentioned. The late (phantom or quintessence) universe filled with dark fluid with inhomogeneous equation of state (where inhomogeneous terms are originated from the modified gravity) is also described.
The D2 SUSY zoo

We present new supersymmetric solutions of the Dirac-Born-Infeld equations for time-independent D2-branes, including a 1/2 supersymmetric `dyonic' D2-brane and various 1/4 supersymmetric configurations that include `twisted' supertubes, superfunnels with arbitrary planar cross-section, asymptotically planar D2-branes, and non-singular intersections of `magnetic' D2-branes. Our analysis is exhaustive for D2-branes in three space dimensions.
The mic-mac connection inside stars: the interdependence of atomic diffusion and hydrodynamic instabilities

The interdependence of microscopic (atomic) and macroscopic (hydrodynamic) processes inside stars and their consequences for stellar structure and evolution were recognized by Jean-Paul Zahn several decades ago. He was a pioneer in that respect, discussing the importance of the macroscopic motions related to stellar rotation, in competition with the chemical stratification induced by gravitational settling and radiative accelerations. This has been much developed in recent years, in connection with the improvement of observational data, including asteroseismology. Morover, it has been recently discovered that the microscopic atomic diffusion processes can lead to macroscopic results which may infuence in a non negligible way the internal stellar structure, independently of the abundances observed at the surface.
Detection of HC11N in the Cold Dust Cloud TMC-1

Two consecutive rotational transitions of the long cyanopolyyne HC11N, J = 39 → 38 and 38 → 37, have been detected in the cold dust cloud TMC-1 at the frequencies expected from recent laboratory measurements by Travers and coworkers, and at about the expected intensities. The astronomical lines have a mean radial velocity of 5.8(1) km s-1, in good agreement with the shorter cyanopolyynes HC7N and HC9N observed in this very sharp line source [5.82(5) and 5.84(5) km s-1, respectively]. The column density of HC11N is calculated to be 2.8 × 1011 cm-2. The abundance of the cyanopolyynes decreases smoothly with length to HC11N, the decrement from one to the next being about six for the longer carbon chains.
Ordinary and extraordinary hadrons

Resonances and enhancements in meson‐meson scattering can be divided into two classes distinguished by their behavior as the number of colors (Nc) in QCD becomes large: The first are ordinary mesons that become stable as Nc→∞. This class includes textbook qq mesons as well as glueballs and hybrids. The second class, extraordinary mesons, are enhancements that disappear as Nc→∞; they subside into the hadronic continuum. This class includes indistinct and controversial objects that have been classified as qq¯qq mesons or meson‐meson molecules. Ordinary mesons resemble Feshbach resonances while extraordinary mesons look more like effects due to potentials in meson‐meson scattering channels. I build and explore toy models along these lines.
Global existence and uniqueness to the Cauchy problem of the BGK equation with infinite energy

The Bhatnagar–Gross–Krook model of the Boltzmann equation is of great importance in the kinetic theory of rarefied gases. Various existence and uniqueness results have been built under the boundedness of energy. In this paper, we will establish several global existence results to the Bhatnagar–Gross–Krook equation with infinite energy. It heavily relies on a new moments lemma and a new existence and uniqueness theorem of weighted velocity‐spatial L∞ solutions. Copyright © 2015 John Wiley & Sons, Ltd.
A framework for a discrete valued Helmholtz machine

The Helmholtz machine and the wake-sleep learning algorithm are interesting developments in the field of stochastic modelling due to the substitution of complex learning rules by an algorithm which uses two complementary networks which learn from each other with a simple learning rule. However, it is limited in its range of practical applications due to the binary nature of its units. This paper discusses the possibility of allowing the units to take on an arbitrary number of discrete states. Involved in this are the addition of an error term to the energy in the network and the alteration of the wake-sleep algorithm to be stochastic in nature. The difficulties associated with gradient descent in the new network are presented and some possible solutions are discussed.
Extended ensemble theory, spontaneous symmetry breaking, and phase transitions

In this paper, as a personal review, we suppose a possible extension of Gibbs ensemble theory so that it can provide a reasonable description of phase transitions and spontaneous symmetry breaking. The extension is founded on three hypotheses, and can be regarded as a microscopic edition of the Landau phenomenological theory of phase transitions. Within its framework, the stable state of a system is determined by the evolution of order parameter with temperature according to such a principle that the entropy of the system will reach its minimum in this state. The evolution of order parameter can cause a change in representation of the system Hamiltonian; different phases will realize different representations, respectively; a phase transition amounts to a representation transformation. Physically, it turns out that phase transitions originate from the automatic interference among matter waves as the temperature is cooled down. Typical quantum many-body systems are studied with this extended ensemble theory. We regain the Bardeen–Cooper–Schrieffer solution for the weak-coupling superconductivity, and prove that it is stable. We find that negative-temperature and laser phases arise from the same mechanism as phase transitions, and that they are unstable. For the ideal Bose gas, we demonstrate that it will produce Bose–Einstein condensation (BEC) in the thermodynamic limit, which confirms exactly Einstein’s deep physical insight. In contrast, there is no BEC either within the phonon gas in a black body or within the ideal photon gas in a solid body. We prove that it is not admissible to quantize the Dirac field by using Bose–Einstein statistics. We show that a structural phase transition belongs physically to the BEC happening in configuration space, and that a double-well anharmonic system will undergo a structural phase transition at a finite temperature. For the O(N)-symmetric vector model, we demonstrate that it will yield spontaneous symmetry breaking and produce Goldstone bosons; and if it is coupled with a gauge field, the gauge field will obtain a mass (Higgs mechanism). Also, we show that an interacting Bose gas is stable only if the interaction is repulsive. For the weak interaction case, we find that the BEC is a ‘λ-transition’ and its transition temperature can be lowered by the repulsive interaction. In connection with liquid 4He, it is found that the specific heat at constant pressure CP will show a T3 law at low temperatures, which is in agreement with the experiment. If the system is further cooled down, the theory predicts that CP will vanish linearly as , which is anticipating experimental verifications.
A High-mass Protobinary System with Spatially Resolved Circumstellar Accretion Disks and Circumbinary Disk

High-mass multiples might form via fragmentation of self-gravitational disks or alternative scenarios such as disk-assisted capture. However, only a few observational constraints exist on the architecture and disk structure of high-mass protobinaries and their accretion properties. Here, we report the discovery of a close (57.9 ± 0.2 mas = 170 au) high-mass protobinary, IRAS17216-3801, where our VLTI/GRAVITY+AMBER near-infrared interferometry allows us to image the circumstellar disks around the individual components with ∼3 mas resolution. We estimate the component masses to ∼20 and ∼18 M⊙ and find that the radial intensity profiles can be reproduced with an irradiated disk model, where the inner regions are excavated of dust, likely tracing the dust sublimation region in these disks. The circumstellar disks are strongly misaligned with respect to the binary separation vector, which indicates that the tidal forces did not have time to realign the disks, pointing toward a young dynamical age of the system. We constrain the distribution of the Brγ and CO-emitting gas using VLTI/GRAVITY spectro-interferometry and VLT/CRIRES spectro-astrometry and find that the secondary is accreting at a higher rate than the primary. VLT/NACO imaging shows L′-band emission on (3–4)× larger scales than the binary separation, matching the expected dynamical truncation radius for the circumbinary disk. The IRAS17216-3801 system is ∼3× more massive and ∼5× more compact than other high-mass multiplies imaged at infrared wavelength and the first high-mass protobinary system where circumstellar and circumbinary dust disks could be spatially resolved. This opens exciting new opportunities for studying star–disk interactions and the role of multiplicity in high-mass star formation.
“Squashed entanglement”: An additive entanglement measure

In this paper, we present a new entanglement monotone for bipartite quantum states. Its definition is inspired by the so-called intrinsic information of classical cryptography and is given by the halved minimum quantum conditional mutual information over all tripartite state extensions. We derive certain properties of the new measure which we call “squashed entanglement”: it is a lower bound on entanglement of formation and an upper bound on distillable entanglement. Furthermore, it is convex, additive on tensor products, and superadditive in general. Continuity in the state is the only property of our entanglement measure which we cannot provide a proof for. We present some evidence, however, that our quantity has this property, the strongest indication being a conjectured Fannes-type inequality for the conditional von Neumann entropy. This inequality is proved in the classical case.
Two-loop renormalization of quantum gravity simplified

The coefficient of the dimensionally regularized two-loop R 3 divergence of (nonsupersymmetric) gravity theories has recently been shown to change when nondynamical three-forms are added to the theory, or when a pseudoscalar is replaced by the antisymmetric two-form field to which it is dual. This phenomenon involves evanescent operators, whose matrix elements vanish in four dimensions, including the Gauss-Bonnet operator which is also connected to the trace anomaly. On the other hand, these effects appear to have no physical consequences for renormalized scattering processes. In particular, the dependence of the two-loop four-graviton scattering amplitude on the renormalization scale is simple. As a result, we explain this result for any minimally-coupled massless gravity theory with renormalizable matter interactions by using unitarity cuts in four dimensions and never invoking evanescent operators.
Nonlinear Cepheid Pulsation Calculations and Comparison with Linear Theory

Linear and nonlinear pulsation calculations have been carried out on a number of purely radiative classical Cepheid models, using identical input physics and models as nearly identical as is feasible. The models chosen for the companson all had the composition X=0.602, Z=O.044, but some of the linearized calculations were performed using different compositions. Two main mass- luminosity relations have been assumed, one based on evolution calculations with conventional masses, the other with masses reduced by a factor of about 2 for given luminosity. The linear blue instability edges are discussed, and it is concluded that uncertainties in both theory and observation preclude a clear distinction between the above two mass-luminosity relations on the basis of the blue edges alone, although the larger ( evolutionary'') masses are very wealdy favored. Comparison of the two sets of calculations show that, overall, the nonlinear results are consistent with the linear results. In particular, no well- established cases of hard'' self-excited oscillations have been found. The nonlinear calculations suggest that some models which according to the linear theory are simultaneously unstable in both F and 1H moles, can attain an apparently stable finite limiting amplitude in either mede, depending on initial conditions (e.g., directionmore » of evolution). The portion of the instability strip where this kind of behavior is expected to be most likely, is found to correspond, for the adopted composition, to periods around 6-11 days (including both F and 1H periods) if Cepheids have the evolutionary'' mases, and around 2- 4 days if their masses are half as large. Stars lying well above (below) these peried ranges in the instability strip are expected to be predominantly F(1H) pulsators. It is likely that these period ranges would occur at shorter periods with a smaller helium abundance. For example, for Y=0.20 it is estimated that the above period range would be around 2.5-5 days for the evolutionary'' masses. Finally, it is concluded that the large-amplitude mede behavior is predictable from linear theory in certain cases, but not in all. (auth)« less