ShantanuT01/DACTYL-Pretraining huggingface dataset:
The determination of absolute and relative distances of molecular clouds along the line-of-sight towards the central molecular zone (CMZ) is crucial to infer its orbital structure, dynamics, and to understand star formation in the clouds. Recent results by Zoccali et al. 2021 suggest that the G0.253 + 0.016 cloud (the Brick) does not belong to the CMZ. This motivated us to cross check their results computing the absolute and relative distance to the Brick and also to other two molecular clouds (the 50 km/s, and the 20 km/s clouds), and discuss their CMZ membership. We used the colour magnitude diagrams $K_s$ vs. $H-K_s$ to compare stars detected towards the target clouds with stars detected towards three reference regions in the nuclear stellar disc (NSD) and the Galactic bulge. We used red clump (RC) stars to estimate the distance to each region. We obtained that all the clouds present a double RC feature. Such a double RC has been reported in previous work for the NSD, but not for the bulge adjacent to it. We exclude the possibility that the different RC features are located at significantly different distances. The obtained absolute and relative distances are compatible with the Galactic centre distance ($\sim8$ kpc).
We prove a quantitative partial result in support of the Dynamical Mordell-Lang Conjecture (also known as the DML conjecture) in positive characteristic. More precisely, we show the following: given a field $K$ of characteristic $p$, given a semiabelian variety $X$ defined over a finite subfield of $K$ and endowed with a regular self-map $\Phi:X \longrightarrow X$ defined over $K$, given a point $\alpha\in X(K)$ and a subvariety $V\subseteq X$, then the set of all non-negative integers $n$ such that $\Phi^n(\alpha)\in V(K)$ is a union of finitely many arithmetic progressions along with a subset $S$ with the property that there exists a positive real number $A$ (depending only on $N$, $\Phi$, $\alpha$, $V$) such that for each positive integer $M$, we have $$\#\left\{n\in S\colon~ n\le M\right\}\le A\cdot \left(1+\log M\right)^{\dim V}.$$
The quark delocalization and color screening model, a quark potential model, is used for a systematic search of dibaryon candidates in the $u,d$ and $s$ three flavor world. Color screening which appears in unquenched lattice gauge calculations and quark delocalization (which is similar to electron delocalization in molecular physics) are both included. Flavor symmetry breaking and channel coupling effects are studied. The model is constrained not only by baryon ground state properties but also by the $N$-$N$ scattering phase shifts. The deuteron and zero energy di-nucleon resonance are both reproduced qualitatively. The model predicts two extreme types of dibaryonic systems: ``molecular'' like the deuteron, and highly delocalized six-quark systems among which only a few narrow dibaryon resonances occur in the $u,d$ and $s$ three flavor world. Possible high spin dibaryon resonances are emphasized.
The bright X-ray selected BL Lac object 1ES1101--232 shows a flat X-ray spectrum, making it detectable with high statistics over the wide BeppoSAX energy range. We have observed it in two different epochs with BeppoSAX, and found a variation of the flux of about 30% that can be explained by a change in the spectral index above the synchrotron peak. We present here the data and infer limits on the strength of the magnetic field based on models of emission for High-frequency peaked BL Lacs.
Two major apparently unrelated problems, that of the origin of time in the universe associated with quantum gravity and to the entropy in de Sitter cosmological models, are found to have their origin in a single physical phenomenon: the semi-classical tunneling through a classically forbidden region of the cosmological scale function. In this region there is a mixing of the states of quantum matter and those of the semi-classical gravity which produces a thermal mixture of the matter states and hence an "entropy"; this same mixing effect brings about the conversion of a parametric time variable into a physical intrinsic time.
We provide the first numerical evidence for the existence of a tubular phase, predicted by Radzihovsky and Toner (RT), for anisotropic tethered membranes without self-avoidance. Incorporating anisotropy into the bending rigidity of a simple model of a tethered membrane with free boundary conditions, we show that the model indeed has two phase transitions corresponding to the flat-to-tubular and tubular-to-crumpled transitions. For the tubular phase we measure the Flory exponent $\nu_F$ and the roughness exponent $\zeta$. We find $\nu_F=0.305(14)$ and $\zeta=0.895(60)$, which are in reasonable agreement with the theoretical predictions of RT --- $\nu_F=1/4$ and $\zeta=1$.
Photo-to-caricature translation aims to synthesize the caricature as a rendered image exaggerating the features through sketching, pencil strokes, or other artistic drawings. Style rendering and geometry deformation are the most important aspects in photo-to-caricature translation task. To take both into consideration, we propose an unsupervised contrastive photo-to-caricature translation architecture. Considering the intuitive artifacts in the existing methods, we propose a contrastive style loss for style rendering to enforce the similarity between the style of rendered photo and the caricature, and simultaneously enhance its discrepancy to the photos. To obtain an exaggerating deformation in an unpaired/unsupervised fashion, we propose a Distortion Prediction Module (DPM) to predict a set of displacements vectors for each input image while fixing some controlling points, followed by the thin plate spline interpolation for warping. The model is trained on unpaired photo and caricature while can offer bidirectional synthesizing via inputting either a photo or a caricature. Extensive experiments demonstrate that the proposed model is effective to generate hand-drawn like caricatures compared with existing competitors.
Hadron collider cross sections for tt~ production and di-lepton, single-lepton and all-jet decays with up to 2 additional jets are calculated using complete LO matrix elements with 6-, 7- and 8-particle final states. The fixed-width, complex-mass and overall-factor schemes (FWS, CMS & OFS) are employed and the quality of narrow-width and double-pole approximations (NWA & DPA) is investigated for inclusive production and suppressed backgrounds to new particle searches. NWA and DPA cross sections differ by 1% or less. The inclusion of sub- and non-resonant amplitudes effects a cross section increase of 5-8% at pp supercolliders, but only minor changes at the Tevatron. On-shell tt~/Wtb backgrounds for the H --> WW decay in weak boson fusion, the hadronic \tau decay of a heavy H^\pm and the \phi --> hh --> \tau\tau bb~ radion decay at the LHC are updated, with corrections ranging from 3% to 30%. FWS and CMS cross sections are uniformly consistent, but OFS cross sections are up to 6% smaller for some backgrounds.
We recently introduced proportional choosability, a new list analogue of equitable coloring. Like equitable coloring, and unlike list equitable coloring (a.k.a. equitable choosability), proportional choosability bounds sizes of color classes both from above and from below. In this note, we show that a graph is proportionally 2-choosable if and only if it is a linear forest such that its largest component has at most 5 vertices and all of its other components have two or fewer vertices. We also construct examples that show that characterizing equitably 2-choosable graphs is still open.
In this paper we consider the following biharmonic equation with critical exponent $P_\epsilon$ : $\Delta^2 u= Ku^{(n+4)/(n-4)-\epsilon}, u>0$ in $\Omega$ and $u=\Delta u=0$ on $\partial\Omega$, where $\Omega$ is a domain in $R^n$, $n\geq 5$, $\epsilon$ is a small positive parameter and $K$ is smooth positive function. We construct solutions of $P_\epsilon$ which blow up and concentrate at strict local maximum of $K$ either at the boundary or in the interior of $\Omega$. We also construct solutions of $P_\epsilon$ concentrating at an interior strict local minimum of $K$. Finally, we prove a nonexistense result for the corresponding supercritical problem which is in sharp contrast with what happened for $P_\epsilon$.
ew-electron systems confined in quasi one-dimensional quantum dots are studied by the configuration interaction approach. We consider the parity symmetry of states forming Wigner molecules in large quantum dots and find that for the spin-polarized Wigner molecules it strictly depends on the number of electrons. We investigate the spatial spin-ordering in the inner coordinates of the quantum system and conclude that for small dots it has a short-range character and results mainly from the Pauli exclusion principle while the Wigner crystallization in large dots is accompanied by spin ordering over the entire length of the dot.
We prove that in dimension $n \ge 2$ the main singularities of a complex potential $q$ having a certain a priori regularity are contained in the Born approximation $q_\theta$ constructed from fixed angle scattering data. Moreover, ${q-q_\theta}$ can be up to one derivative more regular than $q$ in the Sobolev scale. In fact, this result is optimal, we construct a family of compactly supported and radial potentials for which it is not possible to have more than one derivative gain. Also, these functions show that for $n>3$, the maximum derivative gain can be very small for potentials in the Sobolev scale not having a certain a priori level of regularity which grows with the dimension.
Electrons can be reflected at an interface between two metals because of a dielectric barrier or different properties of the Fermi surface. Andreev reflection allows to directly measure normal reflection when one of the metals is a superconductor. We have investigated normal reflection at interfaces between non-magnetic normal metals and superconducting Nb (Tc = 9.2 K) and Al (Tc = 1.2 K). The distribution of the values of the relative strength of the interface barrier, Z, for a number of contacts of a specific metal combination shows a well-defined peak which can be attributed to Fermi surface mismatch. Our reflection coefficients are generally smaller than those predicted theoretically or those derived from proximity-effect studies of normal-superconductor bi-layers.
Recently, the GeV radiation during the X-ray flare activity in GRB 100728A was detected by Feimi/LAT. Here we study the dynamics and emission properties of collision between two homogeneous shells based on the late internal shock model. The GeV photons can be produced from X-ray flare photons up-scattered by relativistic electrons accelerated by forward-reverse shocks, where involved radiative processes include synchrotron self-Compton and crossing inverse-Compton scattering. By analytical and numerical calculations, the observed spectral properties in GRB 100728A can be well explained.
A recent conjecture of the author and Teng Fang states that there are only finitely many finite simple groups with no cubic graphical regular representation. In this paper, we make a crucial progress towards this conjecture by giving an affirmative answer for groups of Lie type of large rank.
We investigate the dynamics of spontaneous fission in a configuration-interaction (CI) approach. In that formalism the decay rate is governed by an effective interaction coupling the ground-state configuration and a fission doorway configuration, with the interaction strength determined by inverting a high-dimensioned CI Hamiltonian matrix that may have a block-tridiagonal structure. It is shown that the decay rate decreases exponentially with the number of blocks at a rate determined by the largest eigenvalue of a matrix in the block space for Hamiltonians with identical off-diagonal blocks. The theory is greatly simplified by approximations similar in spirit to the adiabatic and the least-action approximations in continuum representations. Here each block is replaced by a single matrix element. While the adiabatic reduction underestimates the coupling, a reduction based on a maximum-coupling approximation works well in a schematic CI model.
We extend the application of the techniques developed within the framework of the pseudo-Hermitian quantum mechanics to study a unitary quantum system described by an imaginary PT-symmetric potential v(x) having a continuous real spectrum. For this potential that has recently been used, in the context of optical potentials, for modelling the propagation of electromagnetic waves travelling in a wave guide half and half filed with gain and absorbing media, we give a perturbative construction of the physical Hilbert space, observables, localized states, and the equivalent Hermitian Hamiltonian. Ignoring terms of order three or higher in the non-Hermiticity parameter zeta, we show that the equivalent Hermitian Hamiltonian has the form $\frac{p^2}{2m}+\frac{\zeta^2}{2}\sum_{n=0}^\infty\{\alpha_n(x),p^{2n}\}$ with $\alpha_n(x)$ vanishing outside an interval that is three times larger than the support of $v(x)$, i.e., in 2/3 of the physical interaction region the potential $v(x)$ vanishes identically. We provide a physical interpretation for this unusual behavior and comment on the classical limit of the system.
We present the results of a multi-wavelength (FUV to I-band) survey of the stellar populations of the globular cluster NGC 6752, using STIS, ACS and WFC3 on board the Hubble Space Telescope. We have confirmed that two previously identified CV candidates are, in fact, dwarf novae which underwent outbursts during our observations. We have also identified previously unknown optical counterparts to two X-ray sources. We estimate the position of the centre of the cluster, and show that the stellar density profile is not well described by a single King model, indicating that this cluster is in a core-collapsed or post-core collapse phase. The colour-magnitude diagram shows a well-populated horizontal branch, numerous blue stragglers and white dwarfs (WDs), as well as 87 sources in the gap region where we expect to find WD - main sequence binaries, including cataclysmic variables (CVs). The X-ray sources and WD binary systems are the most centrally concentrated populations, with dynamically estimated characteristic masses >1.1Msun and >0.8Msun, respectively.
Al-Mg-Si alloys with total solute contents ranging from 0.8 to 1.4 wt.% were solutionised, quenched and then artificially aged (AA) at 180 {\deg}C, after which positron annihilation lifetime spectroscopy was applied to obtain information about precipitation and vacancy evolution during preceding ageing. Hardness and electrical resistivity measurements were carried out to complement these measurements. AA was carried out in four different heating media, which allowed for varying the heating rate from 2.4 K/s to 170 K/s. The main result of the study is that there is a competition between vacancy losses and precipitation. Any precipitation taking place during quenching or during heating to the AA temperature helps to prevent vacancies from going to sinks and allows them to assist in solute clustering. Higher solute content, slower heating to 180 {\deg}C and natural pre-ageing before AA were found to have a comparable effect.
In the present work, the spin-coefficient formalism of Newman and Penrose is used to formulate geometric constraints for the existence of Kerr-Schild groups, i.e. continuous groups of generalized Kerr-Schild transformations. In addition, by characterizing the geometric structure of the deformed Einstein tensor of the generalized Kerr-Schild class, restrictions are imposed on the existence of apparent conservation laws in generic spacetimes, which are defined via considering special Kerr-Schild currents whose associated Kerr-Schild vector fields coincide with timelike Killing vector fields of pairs of stationary background geometries. The feasibility of the derived conditions is demonstrated by considering concrete, suitably simple models of generalized Kerr-Schild spacetimes.
We study Higgs boson production from gluon-gluon fusion at mid-rapidity in high energy proton-nucleus collisions. For this process the presently still little known gluon distribution function $h_1^{\perp g}$ gives a numerically relevant contribution. We show by explicite calculation that using CGC (color glass condensate) model input the result obtained in the naive k_t factorization approach matches the result obtained in the TMD factorization framework for a dilute medium. We also verify the earlier finding that the k_t factorization formalism for Higgs production breaks down in a dense medium. In doing so we formulate a hybrid model which allows one to treat such reactions theoretically.
We present a detailed study of an earth-directed coronal mass ejection (Full halo CME) event happened on 2011 February 15 making use of white light observations by three coronagraphs and radio observations by Wind/WAVES. We applied three different methods to reconstruct the propagation direction and traveling distance of the CME and its driven shock. We measured the kinematics of the CME leading edge from white light images observed by STEREO A and B, tracked the CME-driven shock using the frequency drift observed by Wind/WAVES together with an interplanetary density model, and obtained the equivalent scattering centers of the CME by Polarization Ratio(PR) method. For the first time, we applied PR method to different features distinguished from LASCO/C2 polarimetric observations and calculated their projections onto white light images observed by STEREO A and B. By combining the graduated cylindrical shell (GCS) forward modeling with the PR method, we proposed a new GCS-PR method to derive 3D parameters of a CME observed from a single perspective at Earth. Comparisons between different methods show a good degree of consistence in the derived 3D results.
The Event Horizon Telescope collaboration has revealed the first direct image of a black hole, as per the shadow of a Kerr black hole of general relativity. However, other Kerr-like rotating black holes of modified gravity theories cannot be ignored, and they are essential as they offer an arena in which these theories can be tested through astrophysical observation. This motivates us to investigate asymptotically de Sitter rotating black holes wherein interpreting the cosmological constant $\Lambda$ as the vacuum energy leads to a deformation in the vicinity of a black hole -- new Kerr--de Sitter solution, which has a richer geometric structure than the original one. We derive an analytical formula necessary for the shadow of the new Kerr--de Sitter black holes and then visualize the shadow of black holes for various parameters for an observer at given coordinates $(r_0, \theta_0)$ in the domain $(r_0,\; r_c)$ and estimate the cosmological constant $\Lambda$ from its shadow observables. The shadow observables of the new Kerr--de Sitter black holes significantly deviate from the corresponding observables of the Kerr--de Sitter black hole over an appreciable range of the parameter space. Interestingly, we find a finite parameter space for ($\Lambda$, $a$) where the observables of the two black holes are indistinguishable.
We consider the simple extension of the Standard Model in which an additional right handed neutrino propagates along a flat extra dimension, while the Standard Model fields are confined on a 3-brane. The fifth dimension is $S^1/Z_2$ orbifold compactified. In this scenario, the neutrino mass can be naturally suppressed. By studying systematically the fundamental parameter space, we show that the strong phenomenological constraints on mixing angles between active and sterile neutrinos (especially those derived from the SNO experiment data) do not conflict with the possibility of generating a realistic neutrino mass spectrum. As a second step, we explore the possibility of a successful leptogenesis through the decays of the Kaluza-Klein excitations of the right handed neutrino.
In two-derivative theories of gravity coupled to matter, charged black holes are self-attractive at large distances, with the force vanishing at zero temperature. However, in the presence of massless scalar fields and four-derivative corrections, zero-temperature black holes no longer need to obey the no-force condition. In this paper, we show how to calculate the long-range force between such black holes. We develop an efficient method for computing the higher-derivative corrections to the scalar charges when the two-derivative theory has a shift symmetry, and compute the resulting force in a variety of examples. We find that higher-derivative corrected black holes may be self-attractive or self-repulsive, depending on the value of the Wilson coefficients and the VEVs of scalar moduli. Indeed, we find black hole solutions which are both superextremal and self-attractive. Furthermore, we present examples where no choice of higher-derivative coefficients allows for self-repulsive black hole states in all directions in charge space. This suggests that, unlike the Weak Gravity Conjecture, which may be satisfied by the black hole spectrum alone, the Repulsive Force Conjecture requires additional constraints on the spectrum of charged particles.
The kinematic end-point technique for measuring the masses of supersymmetric particles in R-Parity conserving models at hadron colliders is re-examined with a focus on exploiting additional constraints arising from correlations in invariant mass observables. The use of such correlations is shown to potentially resolve the ambiguity in the interpretation of quark+lepton end-points and enable discrimination between sequential two-body and three-body lepton-producing decays. The use of these techniques is shown to improve the SUSY particle mass measurement precision for the SPS1a benchmark model by at least 20-30% compared to the conventional end-point technique.
We apply the theory of height zeta functions to study the asymptotic distribution of rational points of bounded height on projective equivariant compactifications of semi-direct products.
We investigate the thermal properties of the inner crust of a neutron star using the Hartree-Fock-Bogoliubov (HFB) formalism at finite temperature. We compare our results with the ones obtained solving the same equations, but within the BCS approximation. We observe that for the outermost regions of the inner crust, the two methods can show important differences, in particular when we use them to calculate the neutron specific heat of the system.
We consider full scaling limits of planar nearcritical percolation in the Quad-Crossing-Topology introduced by Schramm and Smirnov. We show that two nearcritical scaling limits with different parameters are singular with respect to each other. The results hold for percolation models on rather general lattices, including bond percolation on the square lattice and site percolation on the triangular lattice.
The mechanical properties of $\beta$-Sn single crystals have been systematically investigated using a combined methodology of micropillar tests and rate-dependent crystal plasticity modelling. The slip strength and rate sensitivity of several key slip systems within $\beta$-Sn single crystals have been determined. Consistency between the numerically predicted and experimentally observed slip traces has been shown for pillars oriented to activate single and double slip. Subsequently, the temperature-dependent, intermetallic-size-governing behaviour of a polycrystal $\beta$-Sn-rich alloy SAC305 (96.5Sn-3Ag-0.5Cu wt%) is predicted through a multi-scale homogenization approach, and the predicted temperature- and rate-sensitivity reproduce independent experimental results. The integrated experimental and numerical approaches provide mechanistic understanding and fundamental material properties of microstructure-sensitive behaviour of electronic solders subject to thermomechanical loading, including thermal fatigue.