ShantanuT01/DACTYL-Pretraining huggingface dataset:
The effects of a long range electronic potential on a one dimensional commensurate Charge Density Wave (CDW) state are investigated. Using numerical techniques it is shown that a transition to a metallic ground state is reached as the range of the electron-electron repulsion increases. In this metallic state, the optical conductivity exhibits a large Drude weight. Possible interpretations of our results are discussed.
Let K be an algebraic number field and O_K be its ring of integers. Let S_K be the set of elements in O_K which are sums of squares in O_K and s(O_K) the minimal number of squares necessary to represent -1in O_K. Let g( S_K ) be the smallest positive integer t such that every element in S_K is a sum of t squares in O_K. Here K is generated over field of rational number by square root of m and -n , where m congruent 3 mod 4 and n congruent 1 mod 4 are two distinct positive square free integers, we prove that $ S_K= O_K. We also prove that g(O_ K) less or equals to s(O_K)+1 or s(O_K)+2. Applying this, we shows that if s(O_K)=2, then g(O_K)=3. This work is continuation of a recent study initiated by Zhang and Ji .
We report new wide-field (~ 4 x 4 square arcmin) MUSE observations of the Blue Infalling Group (BIG), a compact group of galaxies located at a projected distance of ~ 150 kpc from the X-Ray centre of the A1367 cluster at z = 0.021. Our MUSE observations map in detail the extended ionized gas, primarily traced by H$\alpha$ emission, in between the members of the group. The gas morphology and its kinematics appear consistent with a tidal origin due to galaxy encounters, as also supported by the disturbed kinematics visible in one of the group members and the presence of tidal dwarf systems. A diffuse tail extending in the direction opposite to the cluster centre is also detected, hinting at a global ram-pressure stripping of the intra-group material as BIG falls inside A1367. Based on the analysis of spatially-resolved emission line maps, we identify multiple ionization mechanisms for the diffuse gas filaments, including in situ photoionization from embedded HII regions and shocks. Combining spatially resolved kinematics and line ratios, we rule out the association of the most massive galaxy, CGCG097-120, with the group as this system appears to be decoupled from the intragroup medium and subject to strong ram pressure as it falls into A1367. Through our new analysis, we conclude that BIG is shaped by pre-processing produced by gravitational interactions in the local group environment combined with ram pressure stripping by the global cluster halo.
3D point cloud segmentation remains challenging for structureless and textureless regions. We present a new unified point-based framework for 3D point cloud segmentation that effectively optimizes pixel-level features, geometrical structures and global context priors of an entire scene. By back-projecting 2D image features into 3D coordinates, our network learns 2D textural appearance and 3D structural features in a unified framework. In addition, we investigate a global context prior to obtain a better prediction. We evaluate our framework on ScanNet online benchmark and show that our method outperforms several state-of-the-art approaches. We explore synthesizing camera poses in 3D reconstructed scenes for achieving higher performance. In-depth analysis on feature combinations and synthetic camera pose verify that features from different modalities benefit each other and dense camera pose sampling further improves the segmentation results.
We present data on the modulation of the dark port power at the free spectral range frequency of the LIGO 4 km interferometers. It is found that the power is modulated exactly at the tidal frequencies to a precision of 6e-9 Hz.
We investigate the evolution of matter density perturbations and some properties of the peculiar velocity field for a special class of exponential potentials in a scalar field model for quintessence, for which a general exact solution is known. The data from the 2-degree Field Galaxy Redshift Survey (2dFGRS) suggest a value of the today pressureless matter density Omega_M0 = 0.18 +- 0.05.
We consider the reduction of an elliptic curve defined over the rational numbers modulo primes in a given arithmetic progression and investigate how often the subgroup of rational points of this reduced curve is cyclic as a special case of Serre's Cyclicity Conjecture.
We used the Australia Telescope Compact Array to map a large field of approximately $2^{\circ} \times 2^{\circ}$ around the Sculptor group galaxy NGC~300 in the 21-cm line emission of neutral hydrogen. We achieved a $5 \sigma$ \ion{H}{i} column density sensitivity of $10^{19}~\mathrm{cm}^{-2}$ over a spectral channel width of $8~\mathrm{km \, s}^{-1}$ for emission filling the $180'' \times 88''$ synthesised beam. The corresponding \ion{H}{i} mass sensitivity is $1.2 \times 10^{5}~\mathrm{M}_{\odot}$, assuming a distance of $1.9~\mathrm{Mpc}$. For the first time, the vast \ion{H}{i} disc of NGC~300 has been mapped over its entire extent at a moderately high spatial resolution of about $1~\mathrm{kpc}$.   NGC~300 is characterised by a dense inner \ion{H}{i} disc, well aligned with the optical disc of $290^{\circ}$ orientation angle, and an extended outer \ion{H}{i} disc with a major axis of more than $1^{\circ}$ on the sky (equivalent to a diameter of about $35~\mathrm{kpc}$) and a different orientation angle of $332^{\circ}$. A significant fraction (about 43~per cent) of the total detected \ion{H}{i} mass of $1.5 \times 10^{9}~\mathrm{M}_{\odot}$ resides within the extended outer disc. We fitted a tilted ring model to the velocity field of NGC~300 to derive the rotation curve out to a radius of $18.4~\mathrm{kpc}$, almost twice the range of previous rotation curve studies. The rotation curve rises to a maximum velocity of almost $100~\mathrm{km \, s}^{-1}$ and then gently decreases again in the outer disc beyond a radius of about $10~\mathrm{kpc}$. Mass models fitted to the derived rotation curve yield good fits for Burkert and NFW dark matter halo models, whereas pseudo-isothermal halo models and MOND-based models both struggle to cope with the declining rotation curve.   We also observe significant asymmetries in the outer \ion{H}{i} disc of NGC~300, in particular near the edge of the disc, which are possibly due to ram pressure stripping of gas by the intergalactic medium (IGM) of the Sculptor group. Our estimates show that ram pressure stripping can occur under reasonable assumptions on the density of the IGM and the relative velocity of NGC~300. The asymmetries in the gas disc suggest a proper motion of NGC~300 toward the south-east. At the same time, our data exclude IGM densities of significantly higher than $10^{-5}~\mathrm{cm}^{-3}$ in the vicinity of NGC~300, as otherwise the outer gas disc would have been stripped.
In this paper, we study the superconvergence phenomenon in the free central limit theorem for identically distributed, unbounded summands. We prove not only the uniform convergence of the densities to the semicircular density but also their $L^p$-convergence to the same limit for $p>1/2$. Moreover, an entropic central limit theorem is obtained as a consequence of the above results.
We give a number of results on approximations of Markov kernels in total variation and Wasserstein norms weighted by a Lyapunov function. The results are applied to examples from Bayesian statistics where approximations to transition kernels are made to reduce computational costs.
We present a class of higher dimensional solutions to Einstein-Maxwell equations in d-dimensions. These solutions are asymptotically locally flat, de-Sitter, or anti-de Sitter space-times. The solutions we obtained depend on two extra parameters other than the mass and the nut charge. These two parameters are the electric charge, q and the electric potential at infinity, V, which has a non-trivial contribution. We Analyze the conditions one can impose to obtain Taub-Nut or Taub-Bolt space-times, including the four-dimensional case. We found that in the nut case these conditions coincide with that coming from the regularity of the one-form potential at the horizon. Furthermore, the mass parameter for the higher dimensional solutions depends on the nut charge and the electric charge or the potential at infinity.
In this paper, we establish a Schmidt's subspace theorem for moving hypersurfaces in weakly subgeneral position. Our result generalizes the previous results on Schmidt's theorem for the case of moving hypersurfaces.
Let $P$ be a Markov kernel on a measurable space $\X$ and let $V:\X\r[1,+\infty)$. This paper provides explicit connections between the $V$-geometric ergodicity of $P$ and that of finite-rank nonnegative sub-Markov kernels $\Pc_k$ approximating $P$. A special attention is paid to obtain an efficient way to specify the convergence rate for $P$ from that of $\Pc_k$ and conversely. Furthermore, explicit bounds are obtained for the total variation distance between the $P$-invariant probability measure and the $\Pc_k$-invariant positive measure. The proofs are based on the Keller-Liverani perturbation theorem which requires an accurate control of the essential spectral radius of $P$ on usual weighted supremum spaces. Such computable bounds are derived in terms of standard drift conditions. Our spectral procedure to estimate both the convergence rate and the invariant probability measure of $P$ is applied to truncation of discrete Markov kernels on $\X:=\N$.
We derive analytic expressions for high energy $2 \to 2$ off-shell scattering amplitudes of weak vector bosons. They are obtained from six fermion final states in processes of the type $e^+ e^- \to \bar\nu_e + (WW) + \nu_e \to \bar\nu_e + (l\nu)(l\nu) + \nu_e$. As an application we reconsider the unitarity bounds on the Higgs mass. Particular attention is given to the role of the photon exchange which has not been considered in earlier investigations; we find that the photon weakens the bound of the Higgs mass.
Simulations of core-collapse supernovae (CCSNe) result in successful explosions once the neutrino luminosity exceeds a critical curve, and recent simulations indicate that turbulence further enables explosion by reducing this critical neutrino luminosity. We propose a theoretical framework to derive this result and take the first steps by deriving the governing mean-field equations. Using Reynolds decomposition, we decompose flow variables into background and turbulent flows and derive self-consistent averaged equations for their evolution. As basic requirements for the CCSN problem, these equations naturally incorporate steady-state accretion, neutrino heating and cooling, non-zero entropy gradients, and turbulence terms associated with buoyant driving, redistribution, and dissipation. Furthermore, analysis of two-dimensional (2D) CCSN simulations validate these Reynolds-averaged equations, and we show that the physics of turbulence entirely accounts for the differences between 1D and 2D CCSN simulations. As a prelude to deriving the reduction in the critical luminosity, we identify the turbulent terms that most influence the conditions for explosion. Generically, turbulence equations require closure models, but these closure models depend upon the macroscopic properties of the flow. To derive a closure model that is appropriate for CCSNe, we cull the literature for relevant closure models and compare each with 2D simulations. These models employ local closure approximations and fail to reproduce the global properties of neutrino-driven turbulence. Motivated by the generic failure of these local models, we propose an original model for turbulence which incorporates global properties of the flow. This global model accurately reproduces the turbulence profiles and evolution of 2D CCSN simulations.
The Standard Model of particle physics is assumed to be a low-energy effective theory with new physics theoretically motivated to be around TeV scale. The dissertation presents theories with new physics beyond the Standard Model at the TeV scale testable in the current High Energy Colliders. The study on leptoquarks gauge bosons in reference to TopSU(5) model in chapter 2 showed that their discovery mass range extends upto 1.5 TeV at 14 TeV LHC with luminosity of 100 $fb^{-1}$. On the other hand, in chapter 3 we studied the collider phenomenology of TeV scale mirror fermions in Left-Right Mirror model finding that the reaches for the mirror quarks goes upto $750$ GeV at the $14$ TeV LHC with $~300 ~fb^{-1}$ luminosity. In chapter 4 we have enlarged the bosonic symmetry to fermi-bose symmetry e.g. supersymmetry and have shown that SUSY with non-universalities in gaugino or scalar masses within high scale SUGRA set up can still be accessible at LHC with 14 TeV. In chapter 5, we performed a study in respect to the $e^+e^-$ collider and find that precise measurements of the higgs boson mass splittings upto $\sim 100$ MeV may be possible with high luminosity in the International Linear Collider (ILC). In chapter 6 we have shown that the experimental data on neutrino masses and mixings are consistent with the proposed 4/5 parameter Dirac neutrino models yielding a solution for the neutrino masses with inverted mass hierarchy and large CP violating phase $\delta$ and thus can be tested experimentally. Chapter 7 incorporates a warm dark matter candidate in context of two Higgs doublet model. The model has several testable consequences at LHC. This dissertation presents an endeavor to study beyond standard model (BSM) physics at the TeV scale with testable signals in the Colliders.
We are interested in asymptotic models for the propagation of internal waves at the interface between two shallow layers of immiscible fluid, under the rigid-lid assumption. We review and complete existing works in the literature, in order to offer a unified and comprehensive exposition. Anterior models such as the shallow water and Boussinesq systems, as well as unidirectional models of Camassa-Holm type, are shown to descend from a broad Green-Naghdi model, that we introduce and justify in the sense of consistency. Contrarily to earlier works, our Green-Naghdi model allows a non-flat topography, and horizontal dimension d = 2. Its derivation follows directly from classical results concerning the one-layer case, and we believe such strategy may be used to construct interesting models in different regimes than the shallow-water/shallow-water studied in the present work.
The results on local existence and continuation criteria obtained by G. Rein in [4] are extended to the case with a non-zero cosmological constant. It is also shown that for the spherically symmetric case and a positive cosmological constant there is a large class of initial data with global existence and inflationary asymptotics in the future as in the case of plane or hyperbolic symmetry treated in [7]. Furthermore we analyze the behaviour of the energy-momentum tensor at late times.
RHIC experiments have established jet quenching as a fundamental tool in the study of hot matter in heavy-ion collisions. The energy reached is enough for high-pT inclusive particle studies and one- or two-particle correlations up to pT= 10-20 GeV. The corresponding data are successfully described by a formalism based on radiative energy losses. This formalism needs, however, to be improved for more exclusive observables, in particular for the reconstructed jet properties. Jet reconstruction is a new branch in heavy-ion collisions with very high expectations as a tool for the characterization of the medium properties. We present here an implementation of the jet quenching phenomena based on a modification at the level of the splitting functions in parton showers in standard, general purpose, Monte Carlos as PYTHIA or HERWIG.
We prove that general unions of singularity schemes of multiplicity two in the projective plane have maximal rank.
Tadpole galaxies, with a bright peripheral clump on a faint tail, are morphological types unusual in the nearby universe but very common early on. Low mass local tadpoles were identified and studied photometrically in a previous work, which we complete here analyzing their chemical and dynamical properties. We measure Halpha velocity curves of seven local tadpoles, representing 50% of the initial sample. Five of them show evidence for rotation (sim 70%), and a sixth target hints at it. Often the center of rotation is spatially offset with respect to the tadpole head (3 out of 5 cases). The size and velocity dispersion of the heads are typical of giant HII regions, and three of them yield dynamical masses in fair agreement with their stellar masses as inferred from photometry. In four cases the velocity dispersion at the head is reduced with respect to its immediate surroundings. The oxygen metallicity estimated from [NII]6583/Halpha often shows significant spatial variations across the galaxies (sim 0.5 dex), being smallest at the head and larger elsewhere. The resulting chemical abundance gradients are opposite to the ones observed in local spirals, but agrees with disk galaxies at high redshift. We interpret the metallicity variation as a sign of external gas accretion (cold-flows) onto the head of the tadpole. The galaxies are low metallicity outliers of the mass-metallicity relationship. In particular, two of the tadpole heads are extremely metal poor, with a metallicity smaller than a tenth of the solar value. These two targets are also very young (ages smaller than 5 Myr). All these results combined are consistent with the local tadpole galaxies being disks in early stages of assembling, with their star formation sustained by accretion of external metal poor gas.
We study the possibility of detecting noncommutative QED through neutral Higgs boson pair production at (gamma--gamma) collider. This is based on the assumption that H^0 interacts directly with photon as suggested by symmetry considerations. The sensitivity of the cross-section to the noncommutative scale (Lambda_{NC}) and Higgs mass is investigated.
We present the first application of a new foreground removal pipeline to the current leading HI intensity mapping dataset, obtained by the Green Bank Telescope (GBT). We study the 15hr and 1hr field data of the GBT observations previously presented in Masui et al (2013) and Switzer et al (2013), covering about 41 square degrees at 0.6<z<1.0, for which cross-correlations may be measured with the galaxy distribution of the WiggleZ Dark Energy Survey. In the presented pipeline, we subtract the Galactic foreground continuum and the point source contamination using an independent component analysis technique (fastica), and develop a Fourier-based optimal estimator to compute the temperature power spectrum of the intensity maps and cross-correlation with the galaxy survey data. We show that fastica is a reliable tool to subtract diffuse and point-source emission through the non-Gaussian nature of their probability distributions. The temperature power spectra of the intensity maps is dominated by instrumental noise on small scales which fastica, as a conservative subtraction technique of non-Gaussian signals, can not mitigate. However, we determine similar GBT-WiggleZ cross-correlation measurements to those obtained by the Singular Value Decomposition (SVD) method, and confirm that foreground subtraction with fastica is robust against 21cm signal loss, as seen by the converged amplitude of these cross-correlation measurements. We conclude that SVD and fastica are complementary methods to investigate the foregrounds and noise systematics present in intensity mapping datasets.
We here report a spectroscopic monitor for the supernova SN\,2017iuk associated with the long-duration low-luminosity gamma-ray burst GRB\,171205A at a redshift of 0.037, which is up to now the third GRB-SN event away from us. Our spectroscopic observations and spectral analysis allow us to identify SN\,2017iuk as a typical broad-line type Ic SN. A comparison study suggests that the type-IcBL SN\,2017iuk resembles to SN\,2006aj in following aspects: 1) similar spectra at the nearby epochs, 2) comparable evolution of the photospheric velocity obtained from the measurements based on both \ion{Si}{2}$\lambda$6355 line and spectral modeling, and 3) comparable explosion parameters. This analogy could imply a formation of a neutron star in the core-collapse of GRB\,171205A/SN\,2017iuk as previously suggested in GRB\,060218/SN\,2006aj. The properties of the host galaxy is discussed, which suggests that GRB\,171205A/SN\,2017iuk occurred in an early type (S0), high-mass, starforming galaxy with low specific SFR and solar metallicity.
An eclipsing binary with an orbital period of 62 days has been discovered in HD 328058 and studied by UBVIcHalpha photometry. Combining the results of light curve modelling with existing stellar models and known B3-shell spectral type of the primary star then allowed a reliable estimation of the mass, radius and effective temperature of both components: about 6.9 Msun, 5.2 Rsun and 17600 K for the primary star, and about 0.78 Msun, 1.20 Rsun and 56000 K for the hot subdwarf companion of type sdO. Obviously, this binary has been created by mass transfer of the envelope of the sdO progenitor to our primary star, now being a rapidly rotating shell star. Its spheroidal distortion and its decretion disk can be studied here unusually well.
Globular star clusters that formed at the same cosmic time may have evolved rather differently from a dynamical point of view (because that evolution depends on the internal environment) through a variety of processes that tend progressively to segregate stars more massive than the average towards the cluster centre. Therefore clusters with the same chronological age may have reached quite different stages of their dynamical history (that is, they may have different dynamical ages). Blue straggler stars have masses greater than those at the turn-off point on the main sequence and therefore must be the result of either a collision or a mass-transfer event. Because they are among the most massive and luminous objects in old clusters, they can be used as test particles with which to probe dynamical evolution. Here we report that globular clusters can be grouped into a few distinct families on the basis of the radial distribution of blue stragglers. This grouping corresponds well to an effective ranking of the dynamical stage reached by stellar systems, thereby permitting a direct measure of the cluster dynamical age purely from observed properties.
Motivated by recently developed interest to the distribution of $q$-ary digits of Mersenne numbers $M_p = 2^p-1$, where $p$ is prime, we estimate rational exponential sums with $M_p$, $p \leq X$, modulo a large power of a fixed odd prime $q$. In turn this immediately implies the normality of strings of $q$-ary digits amongst about $(\log X)^{3/2+o(1)}$ rightmost digits of $M_p$, $p \leq X$. Previous results imply this only for about $(\log X)^{1+o(1)}$ rightmost digits.
We reply to the Comment of Bhattacharya and Karimov on our paper Light deflection by Damour-Solodukhin wormholes and Gauss-Bonnet theorem [arXiv:1811.00768 [gr-qc]]. We address a number of incorrect claims made about our calculations and methodology. We show below that the claims of BK are incorrect, and that there are no problems with the results of \"{O}vg\"{u}n's paper or its implications.