ShantanuT01/DACTYL-Pretraining huggingface dataset:
X-ray diffraction studies showed that the structure of (Sr$_{1-x}$Pr$_x$)TiO$_3$ solid solutions at 300 K changes from the cubic $Pm3m$ to the tetragonal $I4/mcm$ with increasing $x$. The analysis of XANES and EXAFS spectra of the solid solutions revealed that Pr ions are predominantly in the 3+ oxidation state, they substitute for Sr atoms and are on-center regardless of the preparation conditions. The weak dependence of the lattice parameter in (Sr$_{1-x}$Pr$_x$)TiO$_3$ on the Pr concentration was explained by the competition between the relaxation of the Sr--O bond length, which results from the difference in ionic radii of Sr and Pr ions, and the repulsion of positively charged Pr$^{3+}$ and Ti$^{4+}$ ions. It was shown that the most important defects in the crystals are charged Sr vacancies and SrO planar faults; praseodymium does not enter the Sr sites in the planar faults.
NGC 1514 is a complex planetary nebula with a peculiar binary central star (BD+30$^{\circ}$623) consisting of a cool star and a hot companion. To date, the parameters of the two stars have not been firmly stablished. We present a detailed spectral analysis of BD+30$^{\circ}$623 based on intermediate-resolution CAFOS optical spectra and IUE ultraviolet spectra with the goal of deriving the parameters of the two stars. For this purpose, we used an extensive composite grid of Kurucz and T\"ubingen NLTE Model-Atmosphere spectra. From the fitting procedure, in terms of the minimum $\chi^{2}$ method, the best models obtained correspond to an Horizontal-Branch A0 star with $T_{\rm eff}$ = 9850$\pm$150 K, log g = 3.50$\pm$0.25, and a hot companion with $T_{\rm eff}$ between 80000 K and 95000K and a log g $\simeq$ 5.5. To our knowledge, this is the first time that the parameters of both stars have been determined accurately through a detailed spectroscopic analysis.
We investigate the one-dimensional Hubbard model with a confining potential, which may describe cold fermionic atoms trapped in an optical lattice. Combining the variational Monte Carlo simulations with the new stochastic reconfiguration scheme proposed by Sorella, we present an efficient method to systematically treat the ground state properties of the confined system with a site-dependent potential. By taking into account intersite correlations as well as site-dependent on-site correlations, we are able to describe the coexistence of the metallic and Mott insulating regions, which is consistent with other numerical results. Several possible improvements of the trial states are also addressed.
PSR J1811-1736 (P=104 ms) is an old (~1.89 Gyrs) binary pulsar (P_orb=18.8 d) in a highly eccentric orbit (e=0.828) with an unidentified companion. Interestingly enough, the pulsar timing solution yields an estimated companion mass 0.93 M_{\odot}<M_C<1.5 M_{\odot}, compatible with that of a neutron star. As such, it is possible that PSR J1811-1736 is a double neutron star (DNS) system, one of the very few discovered so far. This scenario can be investigated through deep optical/infrared (IR) observations. We used J, H, K-band images, obtained as part of the UK Infrared Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS), and available in the recent Data Release 9 Plus, to search for its undetected companion of the PSR J1811-1736 binary pulsar. We detected a possible companion star to PSR J1811-1736 within the 3 sigma radio position uncertainty (1.32 arcsec), with magnitudes J=18.61+/-0.07, H=16.65+/-0.03, and K=15.46+/-0.02. The star colours are consistent with either a main sequence (MS) star close to the turn-off or a lower red giant branch (RGB) star, at a pulsar distance of ~5.5 kpc and with a reddening of E(B-V)~4.9. The star mass and radius would be compatible with the constraints on the masses and orbital inclination of the binary system inferred from the mass function and the lack of radio eclipses near superior conjunction. Thus, it is possible that it is the companion to PSR J1811-1736. However, based on the star density in the field, we estimated a quite large chance coincidence probability of ~0.27 between the pulsar and the star, which makes the association unlikely. No other star is detected within the 3 sigma pulsar radio position down to J~20.5, H~19.4$ and K~18.6, which would allow us to rule out a MS companion star earlier than a mid-to-late M spectral type.
We present deep infrared (Ks band) imaging polarimetry and radio (1.4 and 4.8 GHz) polarimetry of the enigmatic transient Swift J164449.3+573451. This source appears to be a short lived jet phenomenon in a galaxy at redshift z = 0.354, activated by a sudden mass accretion onto the central massive black hole, possibly caused by the tidal disruption of a star. We aim to find evidence for this scenario through linear polarimetry, as linear polarisation is a sensitive probe of jet physics, source geometry and the various mechanisms giving rise to the observed radiation. We find a formal Ks band polarisation measurement of P_lin = 7.4 +/- 3.5 % (including systematic errors). Our radio observations show continuing brightening of the source, which allows sensitive searches for linear polarisation as a function of time. We find no evidence of linear polarisation at radio wavelengths of 1.4 GHz and 4.8 GHz at any epoch, with the most sensitive 3 sigma limits as deep as 2.1%. These upper limits are in agreement with expectations from scenarios in which the radio emission is produced by the interaction of a relativistic jet with a dense circumsource medium. We further demonstrate how the polarisation properties can be used to derive properties of the jet in Swift J164449.3+573451, exploiting the similarities between this source and the afterglows of gamma-ray bursts.
The concept of monochromatic connectivity was introduced by Caro and Yuster. A path in an edge-colored graph is called a \emph{monochromatic path} if all the edges on the path are colored the same. An edge-coloring of $G$ is a \emph{monochromatic connection coloring} ($MC$-coloring, for short) if there is a monochromatic path joining any two vertices in $G$. The \emph{monochromatic connection number}, denoted by $mc(G)$, is defined to be the maximum number of colors used in an $MC$-coloring of a graph $G$. In this paper, we study the monochromatic connection number on the lexicographical, strong, Cartesian and direct product and present several upper and lower bounds for these products of graphs.
We present evidence of all optical trion generation and emission in undoped single walled carbon nanotubes (SWCNTs). Luminescence spectra, recorded on individual SWCNTs over a large CW excitation intensity range, show trion emission peaks red-shifted with respect to the bright exciton peak. Clear chirality dependence is observed for 22 separate SWCNT species, allowing for determination of electron-hole exchange interaction and trion binding energy contributions. Luminescence data together with ultrafast pump probe experiments on chirality sorted bulk samples suggest that exciton-exciton annihilation processes generate dissociated carriers that allow for trion creation upon a subsequent photon absorption event.
We present the line observations in our ALMA imaging spectral scan toward three deeply buried nuclei in NGC 4418 and Arp 220. We cover 67 GHz in $f_{\rm rest}$=215-697 GHz at about 0.2$"$ (30, 80 pc) resolution. All the nuclei show dense line forests; we report our initial line identification using 55 species. The line velocities generally indicate gas rotation around each nucleus, tracing nuclear disks of $\sim$100 pc sizes. We confirmed the counter-rotation of the nuclear disks in Arp 220 and that of the nuclear disk and the galactic disk in NGC 4418. While the brightest lines exceed 100 K, most of the major lines and many $^{13}$C isotopologues show absorption against even brighter continuum cores of the nuclei. The lines with higher upper-level energies, including those from vibrationally-excited molecules, tend to arise from smaller areas, indicating radially varying conditions in these nuclei. The outflows from the two Arp 220 nuclei cause blueshifted line absorption below the continuum level. The absorption mostly has small spatial offsets from the continuum peaks to indicate the outflow orientations. The bipolar outflow from the western nucleus is also imaged in multiple emission lines, showing the extent of $\sim$1$"$ (400 pc). Redshifted line absorption against the nucleus of NGC 4418 indicates either an inward gas motion or a small collimated outflow slanted to the nuclear disk. We also resolved some previous confusions due to line blending and misidentification.
Relativistic effects in clustering observations have been shown to introduce scale-dependent corrections to the galaxy over-density field on large scales, which may hamper the detection of primordial non-Gaussianity $f_\textrm{NL}$ through the scale-dependent halo bias. The amplitude of relativistic corrections depends not only on the cosmological background expansion, but also on the redshift evolution and sensitivity to the luminosity threshold of the tracer population being examined, as parametrised by the evolution bias $b_\textrm{e}$ and magnification bias $s$. In this work, we propagate luminosity function measurements from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) to $b_\textrm{e}$ and $s$ for the quasar (QSO) sample, and thereby derive constraints on relativistic corrections to its power spectrum multipoles. Although one could mitigate the impact on the $f_\textrm{NL}$ signature by adjusting the redshift range or the luminosity threshold of the tracer sample being considered, we suggest that, for future surveys probing large cosmic volumes, relativistic corrections should be forward modelled from the tracer luminosity function including its uncertainties. This will be important to quasar clustering measurements on scales $k \sim 10^{-3} h \, \textrm{Mpc}^{-1}$ in upcoming surveys such as the Dark Energy Spectroscopic Instrument (DESI), where relativistic corrections can overwhelm the expected $f_\textrm{NL}$ signature at low redshifts $z \lesssim 1$ and become comparable to $f_\textrm{NL} \simeq 1$ in the power spectrum quadrupole at redshifts $z \gtrsim 2.5$.
The modified versions of the bag model equation of state (EoS) are considered. They are constructed to satisfy the main qualitative features observed for the quark-gluon plasma EoS in the lattice QCD calculations. A quantitative comparison with the lattice results at high temperatures T are done in the SU(3) gluodynamics and in the full QCD with dynamical quarks. Our analysis advocates a negative value of the bag constant B.
In this paper, a transformation formula under modular substitutions is derived for a large class of generalized Eisenstein series. Appearing in the transformation formulae are generalizations of Dedekind sums involving the periodic Bernoulli function. Reciprocity theorems are proved for these Dedekind sums. Furthermore, as an application of the transformation formulae, relations between various infinite series and evaluations of several infinite series are deduced. Finally, we consider these sums for some special cases.
We compute the 1-loop correction to the effective action for the string solution in AdS_5 x S^5 dual to the circular Wilson loop. More generically, the method we use can be applied whenever the two dimensional spectral problem factorizes, to regularize and define the fluctuation determinants in terms of solutions of one-dimensional differential equations. A such it can be applied to non-homogeneous solutions both for open and closed strings and to various boundary conditions. In the case of the circular Wilson loop, we obtain, for the 1-loop partition function a result which up to a factor of two matches the expectation from the exact gauge theory computation. The discrepancy can be attributed to an overall constant in the string partition function coming from the normalization of zero modes, which we have not fixed.
We report on VLBI, as well as VLA radio observations of the Type Ib/c supernova 2009bb. The high radio luminosity of this supernova seems to require relativistic outflow, implying that the early radio emission was "engine-driven", that is driven by collimated outflow from a compact object, even though no gamma-ray emission was seen. The radio light curve shows a general decline, with a "bump" near t = 52 d, seen most prominently at 5 GHz. The lightcurve bump could be either engine-driven, or it might represent the turn-on of the normal radio emission from a supernova, driven by interaction with the CSM rather than by the engine. We undertook VLBI observations to resolve SN 2009bb's relativistic outflow. Our observations constrain the angular outer radius at an age of 85 d to be <0.64 mas, corresponding to <4 x 10^17 cm and an average apparent expansion speed of <1.74c. This result is consistent with the moderately relativistic ejecta speeds implied by the radio luminosity and spectrum.
The first-exit time process of an inverse Gaussian L\'evy process is considered. The one-dimensional distribution functions of the process are obtained. They are not infinitely divisible and the tail probabilities decay exponentially. These distribution functions can also be viewed as distribution functions of supremum of the Brownian motion with drift. The density function is shown to solve a fractional PDE and the result is also generalized to tempered stable subordinators. The subordination of this process to the Brownian motion is considered and the underlying PDE of the subordinated process is obtained. The infinite divisibility of the first-exit time of a $\beta$-stable subordinator is also discussed.
We propose a method for determining $\gamma$ using $B^\pm\to D K^\pm$ decays followed by a multibody $D$ decay, such as $D \to K_S \pi^-\pi^+$, $D \to K_S K^-K^+$ and $D \to K_S \pi^-\pi^+\pi^0$. The main advantages of the method is that it uses only Cabibbo allowed $D$ decays, and that large strong phases are expected due to the presence of resonances. Since no knowledge about the resonance structure is needed, $\gamma$ can be extracted without any hadronic uncertainty.
We describe algorithms to compute fixed fields, splitting fields and towers of radical extensions without using polynomial factorisation in towers or constructing any field containing the splitting field, instead extending Galois group computations for this task. We also describe the computation of geometric Galois groups (monodromy groups) and their use in computing absolute factorizations.
For $M$ being a closed manifold or the Euclidean space we present a detailed proof of regularity properties of the composition of $H^s$-regular diffeomorphisms of $M$ for $s > 1/2\dim M + 1$.
We undertake a spectral study of a sample of bright X-ray sources taken from six XMM-Newton fields at high galactic latitudes, where AGN are the most populous class. These six fields were chosen such that the observation had an exposure time more than 60 ksec, had data from the EPIC-pn detector in the full-Frame mode and lying at high galactic latitude $|b| > 25^o$ . The analysis started by fitting the spectra of all sources with an absorbed power-law model, and then we fitted all the spectra with an absorbed power-law with a low energy black-body component model.The sources for which we added a black body gave an F-test probability of 0.01 or less (i.e. at 99% confidence level), were recognized as sources that display soft excess. We perform a comparative analysis of soft excess spectral parameters with respect to the underlying power-law one for sources that satisfy this criterion. Those sources, that do not show evidence for a soft excess, based on the F-test probability at a 99% confidence level, were also fitted with the absorbed power-law with a low energy black-body component model with the black-body temperature fixed at 0.1 and 0.2 keV. We establish upper limits on the soft excess flux for those sources at these two temperatures. Finally we have made use of Aladdin interactive sky atlas and matching with NASA/IPAC Extragalactic Database (NED) to identify the X-ray sources in our sample. For those sources which are identified in the NED catalogue, we make a comparative study of the soft excess phenomenon for different types of systems.
In this paper we introduce the notion of distributional $k$-Hessian associated with Besov type functions in Euclidean $n$-space, $k=2,\ldots,n$. Particularly, inspired by recent work of Baer and Jerison on distributional Hessian determinant, we show that the distributional $k$-Hessian is weak continuous on the Besov space $B(2-\frac{2}{k},k)$, and the result is optimal in the framework of the space $B(s,p)$, i.e., the distributional $k$-Hessian is well defined in $B(s,p)$ if and only if $B(s,p)\subset B_{loc}(2-\frac{2}{k},k)$.
Photo disintegration of the deuteron and photo pionproduction on the deuteron are described in the region of the $\Delta$-resonance. The two reactions are unitarily coupled. A novel definition of electromagnetic exchange currents in the presence of pionproduction is given. Numerical predictions are done for spin-independent and spin-dependent observables of both reactions. The sensitivity of the results with respect to the nucleon-$\Delta$ transition current and with respect to the irreducible nucleon-$\Delta$ potential is studied.
Electron-hole pairs can be excited coherently in a quantum conductor by applying voltage pulses on its contact. We find that these electron-hole pairs can be classified into two kinds, whose excitation probabilities have different dependence on the Faraday flux of the pulse. Most of the pairs are of the first kind, which can be referred to as "normal" pairs. Their excitation probabilities increase nearly monotonically with the flux and saturate to the maximum value 1 when the flux is large enough. In contrast, there exist "abnormal" pairs, whose excitation probabilities can exhibit oscillations with the flux. These pairs can only be excited by pulses with small width. Due to the oscillation of the probabilities, the abnormal pairs can lead to different features in the full counting statistics of the electron-hole pairs for pulses with integer and noninteger fluxes.
We establish the universality theorem for the first four symmetric power L-functions of automorphic forms and their associated Rankin-Selberg L-functions. This generalizes some results of Laurincikas & Matsumoto and Matsumoto respectively.
We focus on Voisin's conjecture on 0-cycles on the self-product of surfaces of geometric genus one, which arises in the context of the Bloch-Beilinson filtration conjecture. We verify this conjecture for the family of Todorov surfaces of type $(2,12)$, giving an explicit description of this family as quotient surfaces of the complete intersection of four quadrics in $\mathbb{P}^{6}$. We give some motivic applications.
In this contribution we show that the theory of neutron transfer to the continuum reactions is an useful tool to study different characteristics of the single particle structure of nuclei. In one example we discuss properties of the single particle resonances in $^{208}Pb$. Another interesting application deals with the neutron breakup from weakly bound nuclei. Here one can use the theoretical calculations to help establishing the angular momentum of the decaying state which is experimentally not known.
We compare the performance of a quantum radar based on two-mode squeezed states with a classical radar system based on correlated thermal noise. With a constraint of equal number of photons $N_S$ transmitted to probe the environment, we find that the quantum setup exhibits an advantage with respect to its classical counterpart of $\sqrt{2}$ in the cross-mode correlations. Amplification of the signal and the idler is considered at different stages of the protocol, showing that no quantum advantage is achievable when a large-enough gain is applied, even when quantum-limited amplifiers are available. We also characterize the minimal type-II error probability decay, given a constraint on the type-I error probability, and find that the optimal decay rate of the type-II error probability in the quantum setup is $\ln(1+1/N_S)$ larger than the optimal classical setup, in the $N_S\ll1$ regime. In addition, we consider the Receiver Operating Characteristic (ROC) curves for the scenario when the idler and the received signal are measured separately, showing that no quantum advantage is present in this case. Our work characterizes the trade-off between quantum correlations and noise in quantum radar systems.
We study the wall-crossing of the moduli spaces $\mathbf{M}^\alpha (d,1)$ of $\alpha$-stable pairs with linear Hilbert polynomial $dm+1$ on the projective plane $\mathbb{P}^2$ as we alter the parameter $\alpha$. When $d$ is 4 and 5, at each wall, the moduli spaces are related by a smooth blow-up morphism followed by a smooth blow-down morphism, where one can describe the blow-up centers geometrically. As a byproduct, we obtain the Poincar\'e polynomials of the moduli space $\mathbf{M}(d,1)$ of stable sheaves. We also discuss the wall-crossing when the number of stable components in Jordan-H\"{o}lder filtrations is three.
In this note, we study the semilinear wave equation with power nonlinearity $|u|^p$ on compact Lie groups. First, we prove a local in time existence result in the energy space via Fourier analysis on compact Lie groups. Then, we prove a blow-up result for the semilinear Cauchy problem for any $p>1$, under suitable sign assumptions for the initial data. Furthermore, sharp lifespan estimates for local (in time) solutions are derived.
The dust disk around Beta Pictoris must be produced by collision or by evaporation of orbiting Kuiper belt-like objects. Here we extend the already proposed Orbiting-Evaporating-Bodies (OEB) scenario in which the disk is a gigantic multi-cometary tail supplied by slowly evaporating bodies like Chiron. We show that the number of these OEBs must be several tens of millions, and that this is consistent with the number of bodies needed to explain the presence of CO and CI in the gaseous disk.   We explore some possible origin of the required perturbation on the OEBs. If dust is produced by evaporation, a planet with an eccentric orbit can explain the observed asymmetry of the disk, because the periastron distribution of the parent bodies are then expected to be non-axisymmetric. Following Malhotra (1995), we investigate the consequence for the Kuiper belt-like objects of the formation and the migration of an outer planet like Neptune in Fernandez's scheme (Fernandez 1982). We find that bodies trapped in resonance with a migrating planet can significantly evaporate, producing a Beta Pictoris-like disk with similar characteristics like opening angle and asymmetry.   We thus show that the Beta Pictoris disk can be a transient phenomenon. The circumstellar disks around main sequence stars can be the signature of the present formation and migration of outer planets.