ShantanuT01/DACTYL-Pretraining huggingface dataset:
Snake states are open trajectories for charged particles propagating in two dimensions under the influence of a spatially varying perpendicular magnetic field. In the quantum limit they are protected edge modes that separate topologically inequivalent ground states and can also occur when the particle density rather than the field is made nonuniform. We examine the correspondence of snake trajectories in single-layer graphene in the quantum limit for two families of domain walls: (a) a uniform doped carrier density in an antisymmetric field profile and (b) antisymmetric carrier distribution in a uniform field. These families support different internal symmetries but the same pattern of boundary and interface currents. We demonstrate that these physically different situations are gauge equivalent when rewritten in a Nambu doubled formulation of the two limiting problems. Using gauge transformations in particle-hole space to connect these problems, we map the protected interfacial modes to the Bogoliubov quasiparticles of an interfacial one-dimensional p-wave paired state. A variational model is introduced to interpret the interfacial solutions of both domain wall problems.
The random field Curie-Weiss model is derived from the classical Curie-Weiss model by replacing the deterministic global magnetic field by random local magnetic fields. This opens up a new and interestingly rich phase structure. In this setting, we derive moderate deviations principles for the random total magnetization $S_n$, which is the partial sum of (dependent) spins. A typical result is that under appropriate assumptions on the distribution of the local external fields there exist a real number $m$, a positive real number $\lambda$, and a positive integer $k$ such that $(S_n-nm)/n^{\alpha}$ satisfies a moderate deviations principle with speed $n^{1-2k(1-\alpha)}$ and rate function $\lambda x^{2k}/(2k)!$, where $1-1/(2(2k-1)) < \alpha < 1$.
We develop algebro-combinatorial tools for computing the Thom polynomials for the Morin singularities $A_i(-)$ ($i\ge 0$). The main tool is the function $F^{(i)}_r$ defined as a combination of Schur functions with certain numerical specializations of Schur polynomials as their coefficients. We show that the Thom polynomial ${\cal T}^{A_i}$ for the singularity $A_i$ (any $i$) associated with maps $({\bf C}^{\bullet},0) \to ({\bf C}^{\bullet+k},0)$, with any parameter $k\ge 0$, under the assumption that $\Sigma^j=\emptyset$ for all $j\ge 2$, is given by $F^{(i)}_{k+1}$. Equivalently, this says that "the 1-part" of ${\cal T}^{A_i}$ equals $F^{(i)}_{k+1}$. We investigate 2 examples when ${\cal T}^{A_i}$ apart from its 1-part consists also of the 2-part being a single Schur function with some multiplicity. Our computations combine the characterization of Thom polynomials via the "method of restriction equations" of Rim\'anyi et al. with the techniques of Schur functions.
We review the mechanism of electroweak baryogenesis. Our focus is on the derivation of quantum transport equations from first principles within the Schwinger-Keldysh formalism. We emphasize the importance of the semiclassical force approach, which provides reliable predictions in most models. In the light of recent electric dipole moment measurements and given the results on new physics searches from collider experiments, the status of electroweak baryogenesis is discussed in a variety of models.
Whereas dc measurements of magnetic susceptibility, $\chi$, fail to distinguish between local and weak itinerant ferromagnets, radio-frequency (rf) measurements of $\chi$ in the ferromagnetic state show dramatic differences between the two. We present sensitive tunnel-diode resonator measurements of $\chi$ in the weak itinerant ferromagnet ZrZn$_2$ at a frequency of 23 MHz. Below Curie temperature, $T_C \approx 26$ K, the susceptibility is seen to increase and pass through a broad maximum at approximately 15 K in zero applied dc magnetic field. Application of a magnetic field reduces the amplitude of the maximum and shifts it to lower temperatures. The existence and evolution this maximum with applied field is not predicted by either the Stoner or self-consistent renormalized (SCR) spin fluctuations theories. For temperatures below $T_C$ both theories derive a zero-field limit expression for $\chi$. We propose a semi-phenomenological model that considers the effect of the internal field from the polarized fraction of the conduction band on the remaining, unpolarized conduction band electrons. The developed model accurate describes the experimental data.
In the Standard Model, there is the single Higgs field, $\phi$, which gives rise to constituent quark and lepton masses. The Yukawa coupling is a highly complex set of $3 \times 3$ matrices, resulting in many textures of quark and lepton masses. In this talk, I present a model which transfers the complexity of the Yukawa coupling matrices to a family of Higgs fields, so that the Yukawa coupling itself becomes a simple interaction. In the context of this Enriched Standard Model, we introduce a new $r$-symmetry in the extended $SU(2)_L \times U(1)_Y \times U(1)_R$ model and show how the $125 \;GeV$ and $750 \;GeV$ resonances may be identified with $H$ and $H'$, the key members of the Higgs family, with $H$ being in every way identifed with the SM Higgs. There are interesting consequences of their $2 \gamma$ decay widths.
Self-testing a quantum device means verifying the existence of a certain quantum state as well as the effect of the associated measurements based only on the statistics of the measurement outcomes. Robust, i.e., error-tolerant, self-testing quantum devices are critical building blocks for quantum cryptographic protocols that rely on imperfect or untrusted quantum devices. We give a criterion which determines whether a given binary XOR game is robust self-testing with the asymptotically optimal error parameter. As an application, we prove that the celebrated CHSH game is an optimally robust self-test. We also prove the same for a family of tests recently proposed by Acin et al. (PRL 108:100402, 2012) for random number generation, thus extending the benefit of the latter tests to allow imperfect or untrusted quantum devices.
We experimentally study the properties of mean and most probable velocity fields in a turbulent von K\'arm\'an flow. These fields are found to be described by two families of functions, as predicted by a recent statistical mechanics study of 3D axisymmetric flows. We show that these functions depend on the viscosity and on the forcing. Furthermore, when the Reynolds number is increased, we exhibit a tendency for Beltramization of the flow, i.e. a velocity-vorticity alignment. This result provides a first experimental evidence of nonlinearity depletion in non-homogeneous non-isotropic turbulent flow.
The main objective of this work is to investigate the role played by Lower Centaurus Crux (LCC) and Upper Centaurus Lupus (UCL), both subcomponents of the Scorpio Centaurus OB association (Sco-Cen), in the formation of the groups beta Pictoris, TW Hydrae and the eta Chamaeleontis cluster. The dynamical evolution of all the stellar groups involved and of the bubbles and shells blown by LCC and UCL are calculated and followed from the past to the present. This leads to a formation scenario in which (1) the groups beta Pictoris, TW Hydrae were formed in the wake of the shells created by LCC and UCL, (2) the young cluster eta Chamaeleontis was born as a consequence of the collision of the shells of LCC and UCL, and (3) the formation of Upper Scorpius (US), the other main subcomponent of the Sco-Cen association, may have been started by the same process that created eta Chamaeleontis.
The effect of Ge substitution on the magnetic, magnetocaloric and transport properties of Ni45Co5Mn38Sb12-xGex (x=0-3) has been investigated. The decrease in the exchange interaction brought by Ge substitution can be seen from the reduction in the magnetization of austenite phase and the increase in the martensitic transition temperature. Large magnetocaloric effect and magnetoresistance have been observed at room temperature, making it a potential material system for various applications.
We present the details and early results from a deep near-infrared survey utilising the NICMOS instrument on the Hubble Space Telescope centred around massive M_* > 10^11 M_0 galaxies at 1.7 < z < 2.9 found within the Great Observatories Origins Deep Survey (GOODS) fields. The GOODS NICMOS Survey (GNS) was designed to obtain deep F160W (H-band) imaging of 80 of these massive galaxies, as well as other colour selected objects such as Lyman-break drop-outs, BzK objects, Distant Red Galaxies, EROs, Spitzer Selected EROs, BX/BM galaxies, as well as sub-mm galaxies. We present in this paper details of the observations, our sample selection, as well as a description of features of the massive galaxies found within our survey fields. This includes: photometric redshifts, rest-frame colours, and stellar masses. We furthermore provide an analysis of the selection methods for finding massive galaxies at high redshifts, including colour selection, and how galaxy populations selected through different methods overlap. We find that a single colour selection method cannot locate all of the massive galaxies, with no one method finding more than 70 percent. We however find that the combination of these colour methods finds nearly all the massive galaxies, as selected by photometric redshifts with the exception of apparently rare blue massive galaxies. By investigating the rest-frame (U-B) vs. M_B diagram for these galaxies we furthermore show that there exists a bimodality in colour-magnitude space at z < 2, driven by stellar mass, such that the most massive galaxies are systematically red up to z~2.5, while lower mass galaxies tend to be blue. We also discuss the number densities for galaxies with stellar masses M_* > 10^11 M_0, whereby we find an increase of a factor of eight between z = 3 and z = 1.5, demonstrating that this is an epoch when massive galaxies establish most of their mass.
Ultra-high energy cosmic ray experimental data are now of very good statistical significance even in the region of the expected GZK feature. The identification of their sources requires sophisticate analysis of their propagation in the extragalactic space. When looking at the details of this propagation some unforeseen features emerge. We will discuss some of these "surprises".
In this work, we have considered a gauged $U(1)_{\rm B-L}$ extension of the Standard Model (SM) with three right handed neutrinos for anomaly cancellation and two additional SM singlet complex scalars with non-trivial B-L charges. One of these is used to spontaneously break the $U(1)_{\rm B-L}$ gauge symmetry, leading to Majorana masses for the neutrinos through the standard Type I seesaw mechanism, while the other becomes the dark matter (DM) candidate in the model. We test the viability of the model to simultaneously explain the DM relic density observed in the CMB data as well as the Galactic Centre (GC) $\gamma$-ray excess seen by Fermi-LAT. We show that for DM masses in the range 40-55 GeV and for a wide range of $U(1)_{\rm B-L}$ gauge boson masses, one can satisfy both these constraints if the additional neutral Higgs scalar has a mass around the resonance region. In studying the dark matter phenomenology and GC excess, we have taken into account theoretical as well as experimental constraints coming from vacuum stability condition, PLANCK bound on DM relic density, LHC and LUX and present allowed areas in the model parameter space consistent with all relevant data, calculate the predicted gamma ray flux from the GC and discuss the related phenomenology.
We describe an implementation for computing holomorphic and skew-holomorphic Jacobi forms of integral weight and scalar index on the full modular group. This implementation is based on formulas derived by one of the authors which express Jacobi forms in terms of modular symbols of elliptic modular forms. Since this method allows to generate a Jacobi eigenform directly from a given modular eigensymbol without reference to the whole ambient space of Jacobi forms it makes it possible to compute Jacobi Hecke eigenforms of large index. We illustrate our method with several examples.
The Madala hypothesis was formulated to explain anomalies in LHC data from run-1. Subsequently, these anomalies have endured into run-2 and been strengthened. This makes the analysis of the proposal highly pertinent, and, since some of the properties of the model are beyond the reach of current collider data it is also important to determine alternative means of analysis. Here, we examine the consequences of WIMPs linked to the Madala hypothesis providing a dark matter candidate and annihilating in the galactic centre of the Milky-Way and the Andromeda galaxy. These targets have been observed to have similar gamma-ray spectra by Fermi-LAT and their emissions have been widely discussed in terms of dark matter annihilation in the literature.   We show that, when the decay branchings of the hidden-sector mediator in the Madala hypothesis are assumed Higgs-like, the emissions of Andromeda and the Milky-Way are not compatible with both being produced by dark matter annihilation, apart from when a steeply contracted NFW profile is assumed for the halos or the WIMP has a mass above 1 TeV. Additionally, similar results are displayed for a wide variety of model independent cases
We report a systematic study of the bias-dependent contact resistance in rubrene single-crystal field-effect transistors with Ni, Co, Cu, Au, and Pt electrodes. We show that the reproducibility in the values of contact resistance strongly depends on the metal, ranging from a factor of two for Ni to more than three orders of magnitude for Au. Surprisingly, FETs with Ni, Co, and Cu contacts exhibits an unexpected reproducibility of the bias-dependent differential conductance of the contacts, once this has been normalized to the value measured at zero bias. This reproducibility may enable the study of microscopic carrier injection processes into organic semiconductors.
Naturally small Majorana neutrino masses arise from nonstandard supersymmetry breaking terms. This mechanism works in the minimal supersymmetric framework and does not require extra particles or new mass scales. It could also be responsible for proton decay even in the absence of Grand Unification.
We present a robust technique for computationally studying surface polariton modes in hybrid materials. We use a semi-classical model that allows us to understand the physics behind the interactions between collective excitations of the hybrid system and develop a scattering and transfer matrix method that imposes the proper boundary conditions to solve Maxwell equations and derive a general equation describing the surface polariton in a heterostructure consisting of N constituent materials. We apply this method to a test structure composed of a topological insulator (TI) and an antiferromagnetic material (AFM) to study the resulting surface Dirac plasmon-phonon-magnon polariton (DPPMP). We find that interactions between the excitations of the two constituents result in the formation of hybridized modes and the emergence of avoided-crossing points in the dispersion relations for the DPPMP. For the specific case of a Bi2Se3 TI material, the polariton branch with low frequency below 2 THz redshifts upon increasing the thickness of TI thin film, which leads to an upper bound on the thickness of the TI layer that will allow an observable signature of strong coupling and the emergence of hybridized states. We also find that the strength of the coupling between the TI and the AFM, which is parameterized by the amplitude of the avoided-crossing splitting between the two polariton branches at the magnon resonance frequency, depends on the magnitude of the magnetic dipole and the line width of the magnon in the AFM material as well as on the Fermi energy of Dirac plasmon in the TI. Finally, we predict that materials with extremely high quality, i.e. low scattering loss rate, are essential to achieve an experimentally-observable strong coupling between a TI and AFM.
We consider a branching Brownian motion in $\mathbb{R}^d$. We prove that there exists a random subset $\Theta$ of $\mathbb{S}^{d-1}$ such that the limit of the derivative martingale exists simultaneously for all directions $\theta \in \Theta$ almost surely. This allows us to define a random measure on $\mathbb{S}^{d-1}$ whose density is given by the derivative martingale.   The proof is based on first moment arguments: we approximate the martingale of interest by a series of processes, which do not take into account the particles that travelled too far away. We show that these new processes are uniformly integrable martingales whose limits can be made to converge to the limit of the original martingale.
The energy spectrum and the emission rate of particles emitted from excited nucleus due to both the evaporation and the splashing (emission from a cold vibrating nucleus) are calculated. We show that the collective motion of the nuclear Fermi liquid is accompanied by direct non-statistical emission of nucleons via the dynamical distortion of the Fermi surface.
We address the problem of a lightly doped spin-liquid through a large-scale density-matrix renormalization group (DMRG) study of the $t$-$J$ model on a Kagome lattice with a small but non-zero concentration, $\delta$, of doped holes. It is now widely accepted that the undoped ($\delta=0$) spin 1/2 Heisenberg antiferromagnet has a spin-liquid groundstate. Theoretical arguments have been presented that light doping of such a spin-liquid could give rise to a high temperature superconductor or an exotic topological Fermi liquid metal (FL$^\ast$). Instead, we infer that the doped holes form an insulating charge-density wave state with one doped-hole per unit cell - i.e. a Wigner crystal (WC). Spin correlations remain short-ranged, as in the spin-liquid parent state, from which we infer that the state is a crystal of spinless holons (WC$^\ast$), rather than of holes. Our results may be relevant to Kagome lattice Herbertsmithite $\rm ZnCu_3(OH)_6Cl_2$ upon doping.
We investigate the level set method (LSM) in a specific quantum context; namely the dipole transition moment for a system with a nontrivial Morse potential. We draw equal moment sets in the two-dimensional space of two important parameters of the potential, namely the depth of the potential and its width. Another variable is introduced as a scale and we see "motions" of the level sets normal to the contours, as in classical contexts such as fluid dynamics or in epitaxial crystal growth. Presumably interpolating the level sets normally by smooth functions such as splines may give a fairly accurate method of combining the variables to keep the dipole moment invariant.
The purpose of this review paper is to summarise the pulsar timing method, to provide an overview of recent research into the spin-down of pulsars over decadal timescales and to highlight the science that can be achieved using high-precision timing of millisecond pulsars.
Temperature and angular momentum induced shape changes in the well deformed 100 Nb have been investigated within the theoretical framework of Statistical theory combined with triaxially deformed Nilson potential and Strutinsky prescription. Two shape coexistence, one in the ground state of 104 Nb between oblate and triaxial shapes and another one between oblate and rarely seen prolate non-collective shapes in excited hot rotating 100 Nb at the mid spin values around 14-16h are reported for the first time. The level density parameter indicates the influence of the shell effects and changes drastically at the shape transition. The band crossing is observed at the sharp shape transition.
In this paper, we prove the existence and uniqueness of nonnegative renormalized solutions for the fractional p(x)-Laplacian problem with L1 data. Our results are new even in the constant exponent fractional p-Laplacian equation case.
It is widely believed that the quark-gluon plasma (QGP) might be formed in the current heavy ion collisions. It is also widely recognized that the relativistic hydrodynamics is one of the best tools for describing the process of expansion and particlization of QGP. In this paper, by taking into account the effects of thermal motion, a hydrodynamic model including phase transition from QGP state to hadronic state is used to analyze the rapidity and transverse momentum distributions of identified charged particles produced in heavy ion collisions. A comparison is made between the theoretical results and experimental data. The theoretical model gives a good description to the corresponding measurements made in Au-Au collisions at RHIC energies.
Strong spin-orbit coupling (SOC) effects of heavy $d$-orbital elements have long been neglected in describing the ground states of their compounds thereby overlooking a variety of fascinating and yet unexplored magnetic and electronic states, until recently. The spin-orbit entangled electrons in such compounds can get stabilized into unusual spin-orbit multiplet $J$-states which warrants severe investigations. Here we show using detailed magnetic and thermodynamic studies and theoretical calculations the ground state of Ba$_3$ZnIr$_2$O$_9$, a 6$H$ hexagonal perovskite is a close realisation of the elusive $J$~=~0 state. However, we find that local Ir moments are spontaneously generated due to the comparable energy scales of the singlet-triplet splitting driven by SOC and the superexchange interaction mediated by strong intra-dimer hopping. While the Ir ions within the structural Ir$_2$O$_9$ dimer prefers to form a spin-orbit singlet state (SOS) with no resultant moment, substantial interdimer exchange interactions from a frustrated lattice ensure quantum fluctuations till the lowest measured temperatures and stabilize a spin-orbital liquid phase.
This paper studies Thick domain wall within the framework of Lyra geometry. Their exact solutions are obtained in the background of a five dimensional space-time. The space-time is nonsingular in its both spatial and temporal behavior. The gravitational field of the wall is shown to be attractive in nature.
We investigated the lifetime of spin wave eigenmodes in periodic and quasiperiodic sequences of Py and Co wires. Those materials differ significantly in damping coefficients, therefore, the spatial distribution of the mode amplitude within the structure is important for the lifetime of collective spin wave excitations. Modes of the lower frequencies prefer to concentrate in Py wires, because of the lower FMR frequency for this material. This inhomogeneous distribution of amplitude of modes (with lower amplitude in material of higher damping and with higher amplitude in material of lower damping) is preferable for extending the lifetime of the collective excitations beyond the volume average of lifetimes for solid materials. We established the relation between the profile of the mode and its lifetime for periodic and quasiperiodic structures. We performed also the comparative studies in order to find the differences resulting from complexity of the structure and enhancement of localization in quasiperiodic system on the lifetime of spin waves.