Miracle-dz/UniFAR-FTUs huggingface dataset:
Superionic hydrogen in Earth's deep interior

Superionic hydrogen was previously thought to be an exotic state predicted and confirmed only in pure H2O ice. In Earth's deep interior, H2O exists in the form of O-H groups in ultra-dense hydrous minerals, which have been proved to be stable even at the conditions of the core-mantle boundary (CMB). However, the superionic states of these hydrous minerals at high P-T have not been investigated. Using first-principles calculations, we found that pyrite structured FeO2Hx (0 <= x <= 1) and d-AlOOH, which have been proposed to be major hydrogen-bearing phases in the deep lower mantle (DLM), contain superionic hydrogen at high P-T conditions. Our observations indicate a universal pathway of the hydroxyl O-H at low pressure transforming to symmetrical O-H-O bonding at high-P low-T, and a superionic state at high-P high-T. The superionicity of hydrous minerals has a major impact on the electrical conductivity and hydrogen transportation behaviors of Earth's lower mantle as well as the CMB.
Heterotic orbifold resolutions as (2,0) gauged linear sigma models

In this work we attempt to bridge the gap between heterotic orbifold models and Calabi‐Yau compactifications using gauged linear sigma models (GLSMs) with (2,0) worldsheet supersymmetry. We associate a specific GLSM to a heterotic orbifold model with twisted states that have non‐vanishing vacuum expectation values (VEVs): The charges of the GLSM superfields are essentially determined by the shifted momenta of these states. When a twisted state contains an oscillator excitation, a fermionic gauging is introduced on the worldsheet, inducing a non‐Abelian gauge bundle, e.g. the standard embedding. However, irrespectively of whether the twisted states contain oscillators or not, they can be interpreted as blow‐up modes, as their VEVs are correlated with sizes of exceptional cycles in the resolved geometry. We show that the GLSM anomaly cancellation conditions ensure that the Bianchi identities are fulfilled for all possible triangulations of a resolution. By considering marginal deformations of a GLSM in the large volume limit we are able to directly determine its effective four dimensional spectrum. In the cases considered the spectra coincide with those computed via index theorems.
Evolution of Raman spectra in Mo 1 − x W x Te 2 alloys

The structural polymorphism in transition metal dichalcogenides (TMDs) provides exciting opportunities for developing advanced electronics. For example, MoTe2 crystallizes in the 2H semiconducting phase at ambient temperature and pressure, but transitions into the 1T′ semimetallic phase at high temperatures. Alloying MoTe2 with WTe2 reduces the energy barrier between these two phases, while also allowing access to the Td Weyl semimetal phase. The Mo1−xWxTe2 alloy system is therefore promising for developing phase change memory technology. However, achieving this goal necessitates a detailed understanding of the phase composition in the MoTe2-WTe2 system. We combine polarization-resolved Raman spectroscopy with X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM) to study Mo1−xWxTe2 alloys over the full compositional range x from 0 to 1. We identify Raman and XRD signatures characteristic of the 2H, 1T′, and Td structural phases that agree with density-functional theory (DFT) calculations, and use them to identify phase fields in the MoTe2-WTe2 system, including single-phase 2H, 1T ′, and Td regions, as well as a two-phase 1T ′ + Td region. Disorder arising from compositional fluctuations in Mo1−xWxTe2 alloys breaks inversion and translational symmetry, leading to the activation of an infrared 1T-MoTe2 mode and the enhancement of a double-resonance Raman process in 2H-Mo1−xWxTe2 alloys. Compositional fluctuations limit the phonon correlation length, which we estimate by fitting the observed asymmetric Raman lineshapes with a phonon confinement model. These observations reveal the important role of disorder in Mo1−xWxTe2 alloys, clarify the structural phase boundaries, and provide a foundation for future explorations of phase transitions and electronic phenomena in this system.
Addressing learning difficulties in Newton's 1st and 3rd Laws through problem based inquiry using Easy Java Simulation

laws, using frictionless constant motion equation and a spring collision equation during impact. Using Physics by Inquiry instructional (PbI) strategy, the simulation and its problem based inquiry worksheet aim to enhance learning of these two Newtonian concepts. We report results from Experimental (N=62 students) and Control (N=67) Groups in 11 multiple-choice questions pre- and post-tests, conducted by three teachers in the school. Results suggest, at 95% confidence level, significant improvement for concept of Newton’s 1
Supersymmetric solutions on SU(4)-structure deformed Stenzel space

The Stenzel space fourfold is a non-compact Calabi-Yau which is a higher dimensional analogue of the deformed conifold. We consider N = (1,1) type IIA, N = 1 M-theory and N = (2,0) type IIB compactifications on this Stenzel space, thus examining the gravity side of potentially higher dimensional analogues of Klebanov-Strassler-like compactifications. We construct families of SU(4)-structures and solve associated moduli spaces, of complex and symplectic structures amongst others. By making use of these, we can construct IIA compactifications on manifolds homeomorphic to the Stenzel space fourfold, but with complex non-CY SU(4)-structures. Such compactifications are sourced by a distribution of NS5-branes. The external metric is asymptotically conformal AdS_3 and should thus be suitable for holography applications.
The Canada–France Ecliptic Plane Survey (CFEPS)—High-latitude Component

The High Ecliptic Latitude (HiLat) extension of the Canada–France Ecliptic Plane Survey (CFEPS), conducted from 2006 June to 2009 July, discovered a set of Trans-Neptunian objects (TNOs) that we report here. The HiLat component was designed to address one of the shortcomings of ecliptic surveys (like CFEPS), their low sensitivity to high-inclination objects. We searched 701 deg2 of sky ranging from 12° to 85° ecliptic latitude and discovered 24 TNOs, with inclinations between 15° and 104°. This survey places a very strong constraint on the inclination distribution of the hot component of the classical Kuiper Belt, ruling out any possibility of a large intrinsic fraction of highly inclined orbits. Using the parameterization of Brown, the HiLat sample combined with CFEPS imposes a width 14° ≤ σ ≤ 15. °5, with a best match for σ = 14. °5. HiLat discovered the first retrograde TNO, 2008 KV42, with an almost polar orbit with inclination 104°, and (418993) = 2009 MS9, a scattering object with perihelion in the region of Saturn’s influence, with a ∼ 400 au and i = 68°.
A Near-infrared Counterpart of 2E1613.5–5053: The Central Source in Supernova Remnant RCW103

On 2016 June 22, 2E 1613.5−5053, the puzzling central compact object in supernova remnant RCW 103 emitted a magnetar-like burst. Using Director’s Discretionary Time, we observed 2E 1613.5−5053 with the Hubble Space Telescope (HST) (WFC3/IR) and we report here on the detection of a previously unseen infrared counterpart. In observations taken on 2016 July 4 and August 11, we detect a new source ( AB mag and AB mag), at the Chandra position of 2E 1613.5−5053, that was not detected in HST/NICMOS images from 2002 August 15 and October 8, to a depth of 24.5 AB mag (F110W) and 25.5 AB mag (F160W). We show that these deep IR observations rule out the possibility of 2E 1613.5−5053 being an accreting binary with a high degree of confidence, but mimic IR emission properties of magnetars and isolated neutron stars. The presence or absence of a low-mass fallback disk cannot be confirmed from our observations.
Ongoing star formation in the protocluster IRAS 22134+5834

The work is supported by the STARFORM Sinergia Project CRSII2_141880 funded by the Swiss National Science Foundation. Y.W. also acknowledges support by the NSFC 11303097 and 11203081, China. A.S. -M. acknowledges support by the collaborative research center project SFB 956, funded by the Deutsche Forschungsgemeinschaft (DFG). G.B. is supported by the Spanish MICINN grant AYA2011-30228-C03-01 (cofunded with FEDER funds). A.P. acknowledges financial support from a UNAM-DGAPA-PAPIIT IA102815 grant, Mexico.
Duality for massive spin two theories in arbitrary dimensions

Using the parent Lagrangian approach we construct a dual formulation, in the sense originally proposed by Curtright and Freund, of a massive spin two Fierz-Pauli theory in arbitrary dimensions D. This is achieved in terms of a mixed symmetry tensor TA[B1B2.BD−2], without the need of auxiliary fields. The relation of this method with an alternative formulation based on a gauge symmetry principle proposed by Zinoviev is elucidated. We show that the latter formulation in four dimensions, with a given gauge fixing together with a definite sequence of auxiliary fields elimination via their equations of motion, leads to the parent Lagrangian already considered by West completed by a Fierz-Pauli mass term, which in turns yields the Curtright-Freund action. This motivates our generalization to arbitrary dimensions leading to the corresponding extension of the four dimensional result. We identify the transverse true degrees of freedom of the dual theory and verify that their number is in accordance with those of the massive Fierz-Pauli field.
Theoretical approach to direct resonant inelastic x-ray scattering on magnets and superconductors

The capability to probe the dispersion of elementary spin, charge, orbital, and lattice excitations has positioned resonant inelastic x-ray scattering (RIXS) at the forefront of photon science. In this work, we will investigate how RIXS can contribute to a deeper understanding of the orbital properties and of the pairing mechanism in unconventional high-temperature superconductors. In particular, we will show how direct RIXS spectra of magnetic excitations can reveal long-range orbital correlations in transition metal compounds, by discriminating different kind of orbital order in magnetic and antiferromagnetic systems. Moreover, we will show how RIXS spectra of quasiparticle excitations in superconductors can measure the superconducting gap magnitude, and reveal the presence of nodal points and phase differences of the superconducting order parameter on the Fermi surface. This can reveal the properties of the underlying pairing mechanism in unconventional superconductors, in particular cuprates and iron pnictides, discriminating between different superconducting order parameter symmetries, such as $s$, $d$ (singlet pairing) and $p$ wave (triplet pairing).
COSMOLOGICAL EVOLUTION OF LONG GAMMA-RAY BURSTS AND THE STAR FORMATION RATE

Gamma-ray bursts (GRBs), by virtue of their high luminosities, can be detected up to very high redshifts and therefore can be excellent probes of the early universe. This task is hampered by the fact that most of their characteristics have a broad range, so we first need to obtain an accurate description of the distribution of these characteristics and, especially, their cosmological evolution. We use a sample of about 200 Swift long GRBs with known redshifts to determine the evolution of the luminosity, formation rate, and the general shape of the luminosity function (LF). In contrast to most other forward-fitting methods of treating this problem, we use the Efron–Petrosian methods, which allow a non-parametric determination of the above quantities. We find a relatively strong luminosity evolution, an LF that can be fitted to a broken power law, and an unusually high formation rate at low redshifts, a rate more than one order of magnitude higher than the star formation rate (SFR). On the other hand, our results seem to agree with the almost constant SFR in redshifts 1–3 and the decline above this redshift.
Algebraic Structure of the Minimum Error Discrimination Problem for Linearly Independent Density Matrices

The minimum error discrimination problem for ensembles of linearly independent pure states are known to have an interesting structure; for such a given ensemble the optimal POVM is given by the pretty good measurment of another ensemble which can be related to the former ensemble by a bijective mapping $\mathscr{R}$ on the "space of ensembles". In this paper we generalize this result to ensembles of general linearly independent states (not necessarily pure) and also give an analytic expression for the inverse of the map, i.e., for $\mathscr{R}^{-1}$. In the process of proving this we also simplify the necessary and sufficient conditions that a POVM needs to satisfy to maximize the probability of success for the MED of an LI ensemble of states. This simplification is then employed to arrive at a rotationally invariant necessary and sufficient conditions of optimality. Using these rotationally invariant conditions it is established that every state of a LI mixed state ensemble can be resolved to a pure state decomposition so that the corresponding pure state ensemble (corresponding to pure states of all mixed states together) has as its optimal POVM a pure state decomposition of the optimal POVM of mixed state ensemble. This gives the necessary and sufficient conditions for the PGM of a LI ensemble to be its optimal POVM; another generalization for the pure state case. Also, these rotationally invariant conditions suggest a technique to give the optimal POVM for an ensemble of LI states. This technique is polynomial in time and outpeforms standard barrier-type interior point SDP in terms of computational complexity.
Causal production of the electromagnetic energy flux and role of the negative energies in Blandford-Znajek process

Blandford-Znajek process, the steady electromagnetic energy extraction from a rotating black hole (BH), is widely believed to work for driving relativistic jets in active galactic nuclei, gamma-ray bursts and Galactic microquasars, although it is still under debate how the Poynting flux is causally produced and how the rotational energy of the BH is reduced. We generically discuss the Kerr BH magnetosphere filled with a collisionless plasma screening the electric field along the magnetic field, extending the arguments of Komissarov and our previous paper, and propose a new picture for resolving the issues. For the magnetic field lines threading the equatorial plane in the ergosphere, we find that the inflow of particles with negative energy as measured in the coordinate basis is generated near that plane as a feedback from the Poynting flux production, which appears to be a similar process to the mechanical Penrose process. For the field lines threading the event horizon, we first show that the concept of the steady inflow of negative electromagnetic energy is not physically essential, partly because the sign of the electromagnetic energy density depends on the coordinates. Then we build an analytical toy model of a time-dependent process both in the Boyer-Lindquist and Kerr-Schild coordinate systems in which the force-free plasma injected continuously is filling a vacuum, and suggest that the structure of the steady outward Poynting flux is causally constructed by the displacement current and the cross-field current at the in-going boundary between the plasma and the vacuum. In the steady state, the Poynting flux is maintained without any electromagnetic source.
Strong frustration due to competing ferromagnetic and antiferromagnetic interactions: magnetic properties of M(VO)2(PO4)2 (M = Ca and Sr)

We present a detailed investigation of the magnetic properties of complex vanadium phosphates M(VO)2(PO4)2 (M = Ca, Sr) by means of magnetization, specific heat, 31P NMR measurements, and band structure calculations. Experimental data evidence the presence of ferro- and antiferromagnetic interactions in M(VO)2(PO4)2 resulting in a nearly vanishing Curie-Weiss temperature \theta_{CW} < 1 K that contrasts with the maximum of magnetic susceptibility at 3 K. Specific heat and NMR measurements also reveal weak exchange couplings with the thermodynamic energy scale J_c = 10-15 K. Additionally, the reduced maximum of the magnetic specific heat indicates strong frustration of the spin system. Band structure calculations show that the spin systems of the M(VO)2(PO4)2 compounds are essentially three-dimensional with the frustration caused by competing ferro- and antiferromagnetic interactions. Both calcium and strontium compounds undergo antiferromagnetic long-range ordering at T_N = 1.5 K and 1.9 K, respectively. The spin model reveals an unusual example of controllable frustration in three-dimensional magnetic systems.
EFFICIENT MERGER OF BINARY SUPERMASSIVE BLACK HOLES IN MERGING GALAXIES

In spherical galaxies, binary supermassive black holes (SMBHs) have difficulty reaching sub-parsec separations due to depletion of stars on orbits that intersect the massive binary—the “final parsec problem. ” Galaxies that form via major mergers are substantially non-spherical, and it has been argued that the centrophilic orbits in triaxial galaxies might provide stars to the massive binary at a high enough rate to avoid stalling. Here we test that idea by carrying out fully self-consistent merger simulations of galaxies containing central SMBHs. We find hardening rates of the massive binaries that are indeed much higher than in spherical models and essentially independent of the number of particles used in the simulations. Binary eccentricities remain high throughout the simulations. Our results constitute a fully stellar-dynamical solution to the final parsec problem and imply a potentially high rate of events for low-frequency gravitational wave detectors like LISA.
Lie 3-Algebra and Multiple M2-branes

Motivated by the recent proposal of an N = 8 supersymmetric action for multiple M2-branes, we study the Lie 3-algebra in detail. In particular, we focus on the fundamental identity and the relation with Nambu-Poisson bracket. Some new algebras not known in the literature are found. Next we consider cubic matrix representations of Lie 3-algebras. We show how to obtain higher dimensional representations by tensor products for a generic 3-algebra. A criterion of reducibility is presented. We also discuss the application of Lie 3-algebra to the membrane physics, including the Basu-Harvey equation and the Bagger-Lambert model.
Rapid crystallization of externally produced ions in a Penning trap

We have studied the cooling dynamics, formation process and geometric structure of mesoscopic crystals of externally produced magnesium ions in a Penning trap. We present a cooling model and measurements for a combination of buffer gas cooling and laser cooling which has been found to reduce the ion kinetic energy by eight orders of magnitude from several hundreds of eV to micro-eV and below within seconds. With ion numbers of the order of 1000 to 100000, such cooling leads to the formation of ion Coulomb crystals which display a characteristic shell structure in agreement with theory of non-neutral plasmas. We show the production and characterization of two-species ion crystals as a means of sympathetic cooling of ions lacking a suitable laser-cooling transition.
Ultra-luminous X-ray sources as neutron stars propelling and accreting at super-critical rates in high-mass X-ray binaries

Ultra-luminous X-ray sources (ULXs) are off-nuclear point sources in nearby galaxies with luminosities well exceeding the Eddington limit for stellar-mass objects. It has been recognized after the discovery of pulsating ULXs (PULXs) that a fraction of these sources could be accreting neutron stars in high-mass X-ray binaries (HMXBs) though the majority of ULXs are lacking in coherent pulsations. The earliest stage of some HMXBs may harbor rapidly rotating neutron stars propelling out the matter transferred by the massive companion. The spin-down power transferred by the neutron-star magnetosphere to the accretion disk at this stage can well exceed the Eddington luminosities and the system appears as a non-pulsating ULX. In this picture, PULXs appear as super-critical mass-accreting descendants of non-pulsating ULXs. We present this evolutionary scenario within a self-consistent model of magnetosphere-disk interaction and discuss the implications of our results on the spin and magnetic field of the neutron star.
SDSS/SEGUE SPECTRAL FEATURE ANALYSIS FOR STELLAR ATMOSPHERIC PARAMETER ESTIMATION

Large-scale and deep sky survey missions are rapidly collecting a large amount of stellar spectra, which necessitate the estimation of atmospheric parameters directly from spectra and make it feasible to statistically investigate latent principles in a large data set. We present a technique for estimating parameters Teff, log g, and [Fe/H] from stellar spectra. With this technique, we first extract features from stellar spectra using the LASSO algorithm; then, the parameters are estimated from the extracted features using the support vector regression. On a subsample of 20,000 stellar spectra from the Sloan Digital Sky Survey (SDSS) with reference parameters provided by the SDSS/SEGUE Spectroscopic Parameter Pipeline, estimation consistency are 0.007458 dex for log Teff (101.609921 K for Teff), 0.189557 dex for log g, and 0.182060 for [Fe/H], where the consistency is evaluated by mean absolute error. Prominent characteristics of the proposed scheme are sparseness, locality, and physical interpretability. In this work, each spectrum consists of 3821 fluxes, and 10, 19, and 14 typical wavelength positions are detected, respectively, for estimating Teff, log g, and [Fe/H]. It is shown that the positions are related to typical lines of stellar spectra. This characteristic is important in investigating physical indications from analysis results. Then, stellar spectra can be described by the individual fluxes on the detected positions (PD) or local integration of fluxes near them (LI). The aforementioned consistency is the result based on features described by LI. If features are described by PD, consistency is 0.009092 dex for log Teff (124.545075 K for Teff), 0.198928 dex for log g, and 0.206814 dex for [Fe/H].
Pairwise quantum and classical correlations in multi-qubits states via linear relative entropy

The pairwise correlations in a multi-qubit state are quantified through a linear variant of relative entropy. In particular, we derive the explicit expressions of total, quantum and classical bipartite correlations. Two different bi-partioning schemes are considered. We discuss the derivation of closest product, quantum-classical and quantum-classical product states. We also investigate the additivity relation between the various pairwise correlations existing in pure and mixed states. As illustration, some special cases are examined.
Galaxies as fluctuations in cosmic stellar liquid

Large self-gravitating stellar systems share with correlated liquids in condensed matter physics a pattern of hierarchical density variations. While it takes the microscopic time resolution to discern the correlated dynamics of the critical opalescence, characteristic astronomical times hide fluctuational dynamics of stellar liquids, where, governed by interstellar correlations, denser clusters of stars assemble and disperse. For a semi-isolated galaxy, these dynamical fluctuations are dense globular clusters. For a galaxy cluster, these dynamical fluctuations are the member galaxies, elliptical ones in the interior. Bright over-density fluctuations, galaxies, are exhibits of only a small fraction of stars found in a cosmic stellar liquid, the dark matter. Here I report a fluctuational gravitational collapse as a property of a self-gravitating system in the virial equilibrium.