ShantanuT01/DACTYL-Pretraining huggingface dataset:
One type of dynamical generation consists in the formation of multiple hadronic resonances from single seed states by incorporating hadronic loop contributions on the level of $s$-wave propagators. Along this line, we study the propagator poles within two models of scalar resonances and report on the status of our work: (i) Using a simple quantum field theory describing the decay of $f_{0}(500)$ into two pions, we may obtain a second, additional pole on the first Riemann sheet below the pion-pion threshold (i.e., a stable state can emerge). (ii) We perform a numerical study of the pole(s) of $a_{0}(1450)$ by using as an input the results obtained in the extended Linear Sigma Model (eLSM). Here, we do not find any additional pole besides the original one, thus we cannot obtain $a_{0}(980)$ as an emerging state. (iii) We finally demonstrate that, although the coupling constants in typical effective models might be large, the next-to-leading-order contribution to the decay amplitude is usually small and can be neglected.
Interactions between disc-surrounded stars might play a vital role in the formation of planetary systems. Here a first parameter study of the effects of encounters on low-mass discs is presented. The dependence of the mass and angular momentum transport on the periastron distance, the relative mass of the encountering stars and eccentricity of the encounter is investigated in detail. This is done for prograde and retrograde coplanar encounters as well as non-coplanar encounters. For distant coplanar encounters our simulation results agree with the analytical approximation of the angular momentum loss by Ostriker(1994). However, for close or high-mass encounters, significant differences to this approximation are found. This is especially so in the case of retrograde encounters, where the analytical result predict no angular momentum loss regardless of the periastron distance whereas the simulations find up to ~ 20% loss for close encounters. For the non-coplanar case a more complex dependency on the inclination between orbital path and disc plane is found than for distant encounters. For the coplanar prograde case new fitting formulae for the mass and angular momentum loss are obtained, which cover the whole range from grazing to distant encounters. In addition, the final disc size and the mass exchange between discs is examined, demonstrating that for equal mass stars in encounters as close as 1.5 the disc radius, the disc size only is reduced by approximately 10%.
Pulse arrival time measurements over fourteen years with the Nanshan 25-m and Parkes 64-m radio telescopes have been used to determine the average profile and timing properties for PSR J1757$-$2421 (B1754$-$24). Analysis of the radio profile data shows a large variation of spectral index across the profile and an unusual increase in component separation with increasing frequency. The timing observations show that PSR B1754$-$24 underwent a large glitch with a fractional increase in spin frequency of $\Delta\nu_{\rm g}/\nu\sim 7.8\times10^{-6}$ in May 2011. At the time of the glitch there was a large permanent jump in the rotational frequency accompanied by two exponential recovery terms with timescales of 15(6) and 97(15) days, respectively.
We investigate the radius distributions (RD) of surfaces obtained with large-scale simulations of radial clusters that belong to the KPZ universality class. For all investigated models, the RDs are given by the Tracy-Widom distribution of the Gaussian unitary ensemble, in agreement with the conjecture of the KPZ universality class for curved surfaces. The quantitative agreement was also confirmed by two-point correlation functions asymptotically given by the covariance of the Airy$_2$ process. Our simulation results fill the last lacking gap of the conjecture that had been recently verified analytically and experimentally.
Fast radio bursts (FRBs) are millisecond-duration, bright radio signals (fluence $\mathrm{0.1 - 100\,Jy\,ms}$) emitted from extragalactic sources of unknown physical origin. The recent CHIME/FRB and STARE2 detection of an extremely bright (fluence $\sim$MJy$\,$ms) radio burst from the Galactic magnetar SGR~1935$+$2154 supports the hypothesis that (at least some) FRBs are emitted by magnetars at cosmological distances. In follow-up observations totalling 522.7$\,$hrs on source, we detect two bright radio bursts with fluences of $112\pm22\mathrm{\,Jy\,ms}$ and $24\pm5\mathrm{\,Jy\,ms}$, respectively. Both bursts appear affected by interstellar scattering and we measure significant linear and circular polarisation for the fainter burst. The bursts are separated in time by $\sim$1.4$\,$s, suggesting a non-Poissonian, clustered emission process -- similar to what has been seen in some repeating FRBs. Together with the burst reported by CHIME/FRB and STARE2, as well as a much fainter burst seen by FAST (fluence 60$\mathrm{\,mJy\,ms}$), our observations demonstrate that SGR 1935+2154 can produce bursts with apparent energies spanning roughly seven orders of magnitude, and that the burst rate is comparable across this range. This raises the question of whether these four bursts arise from similar physical processes, and whether the FRB population distribution extends to very low energies ($\sim10^{30}\,$erg, isotropic equivalent).
Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive electroproduction processes require a generalization of the usual parton distributions for the case when long-distance information is accumulated in nondiagonal matrix elements of quark and gluon light-cone operators. I describe two types of nonperturbative functions parametrizing such matrix elements: double distributions and skewed parton distributions. I discuss their general properties, relation to the usual parton densities and form factors, evolution equations for both types of generalized parton distributions (GPD), models for GPDs and their applications in virtual and real Compton scattering.
A which-way measurement destroys the twin-slit interference pattern. Bohr argued that distinguishing between two slits a distance s apart gives the particle a random momentum transfer \wp of order h/s. This was accepted for more than 60 years, until Scully, Englert and Walther (SEW) proposed a which-way scheme that, they claimed, entailed no momentum transfer. Storey, Tan, Collett and Walls (STCW) in turn proved a theorem that, they claimed, showed that Bohr was right. This work reviews and extends a recent proposal [Wiseman, Phys. Lett. A 311, 285 (2003)] to resolve the issue using a weak-valued probability distribution for momentum transfer, P_wv(\wp). We show that P_wv(\wp) must be wider than h/6s. However, its moments can still be zero because P_wv(\wp) is not necessarily positive definite. Nevertheless, it is measurable in a way understandable to a classical physicist. We introduce a new measure of spread for P_wv(\wp): half of the unit-confidence interval, and conjecture that it is never less than h/4s. For an idealized example with infinitely narrow slits, the moments of P_wv(\wp) and of the momentum distributions are undefined unless a process of apodization is used. We show that by considering successively smoother initial wave functions, successively more moments of both P_wv(\wp) and the momentum distributions become defined. For this example the moments of P_wv(\wp) are zero, and these are equal to the changes in the moments of the momentum distribution. We prove that this relation holds for schemes in which the moments of P_wv(\wp) are non-zero, but only for the first two moments. We also compare these moments to those of two other momentum-transfer distributions and \hat{p}_f-\hat{p}_i. We find agreement between all of these, but again only for the first two moments.
We apply the Gauss-Codacci formalism to brane worlds scenario within the framework of Brans-Dicke gravity. The compactification is taken from six to five dimensions in order to formalize brane-world models with hybrid compactification in scalar-tensor theories.
We study a dynamic model of information provision. A state of nature evolves according to a Markov chain. An informed advisor decides how much information to provide to an uninformed decision maker, so as to influence his short-term decisions. We deal with a stylized class of situations, in which the decision maker has a risky action and a safe action, and the payoff to the advisor only depends on the action chosen by the decision maker. The greedy disclosure policy is the policy which, at each round, minimizes the amount of information being disclosed in that round, under the constraint that it maximizes the current payoff of the advisor. We prove that the greedy policy is optimal in many cases -- but not always.
For the first time, the tilted axis cranking covariant density functional theory with pairing correlations has been formulated and implemented in a fully self-consistent and microscopic way to investigate the evolution of the spin axis and the pairing effects in rotating triaxial nuclei. The measured energy spectrum and transition probabilities for the Nd-135 yrast band are reproduced well without any ad hoc renormalization factors when pairing effects are taken into account. A transition from collective to chiral rotation has been demonstrated. It is found that pairing correlations introduce additional admixtures in the single-particle orbitals, and, thus, influence the structure of tilted axis rotating nuclei by reducing the magnitude of the proton and neutron angular momenta while merging their direction.
Let $E$ be an abelian scheme over a geometrically connected variety $X$ defined over $k$, a finitely generated field over $\mathbb{Q}$. Let $\eta$ be the generic point of $X$ and $x\in X$ a closed point. If $\mathfrak{g}_l$ and $(\mathfrak{g}_l)_x$ are the Lie algebras of the $l$-adic Galois representations for abelian varieties $E_{\eta}$ and $E_x$, then $(\mathfrak{g}_l)_x$ is embedded in $\mathfrak{g}_l$ by specialization. We prove that the set $\{x\in X$ closed point $| (\mathfrak{g}_l)_x\subsetneq \mathfrak{g}_l\}$ is independent of $l$ and confirm Conjecture 5.5 in [2].
We present a novel learning framework for vehicle recognition from a single RGB image. Unlike existing methods which only use attention mechanisms to locate 2D discriminative information, our work learns a novel 3D perspective feature representation of a vehicle, which is then fused with 2D appearance feature to predict the category. The framework is composed of a global network (GN), a 3D perspective network (3DPN), and a fusion network. The GN is used to locate the region of interest (RoI) and generate the 2D global feature. With the assistance of the RoI, the 3DPN estimates the 3D bounding box under the guidance of the proposed vanishing point loss, which provides a perspective geometry constraint. Then the proposed 3D representation is generated by eliminating the viewpoint variance of the 3D bounding box using perspective transformation. Finally, the 3D and 2D feature are fused to predict the category of the vehicle. We present qualitative and quantitative results on the vehicle classification and verification tasks in the BoxCars dataset. The results demonstrate that, by learning such a concise 3D representation, we can achieve superior performance to methods that only use 2D information while retain 3D meaningful information without the challenge of requiring a 3D CAD model.
We construct extremal, spherically symmetric black hole solutions to 4D supergravity with charge assignments that preclude BPS-saturation. In particular, we determine the ground state energy as a function of charges and moduli. We find that the mass of the non-BPS black hole remains that of a marginal bound state of four basic constituents throughout the entire moduli space and that there is always a non-zero gap above the BPS bound.
We derive an effective spin Hamiltonian for the one-dimensional half-filled asymmetric ionic Hubbard model with alternating on-site interaction in the limit of strong repulsion. It is shown that the effective Hamiltonian is that of a spin $S=1/2$ anisotropic $XXZ$ Heisenberg chain with alternating next-nearest-neighbor and three-spin couplings in the presence of a uniform and a staggered magnetic field.
A fluctuation relation is derived to extract the order parameter function $q(x)$ in weakly ergodic systems. The relation is based on measuring and classifying entropy production fluctuations according to the value of the overlap $q$ between configurations. For a fixed value of $q$, entropy production fluctuations are Gaussian distributed allowing us to derive the quasi-FDT so characteristic of aging systems. The theory is validated by extracting the $q(x)$ in various types of glassy models. It might be generally applicable to other nonequilibrium systems and experimental small systems.
We report new results of a campaign to find Wolf-Rayet and O (WR/O) stars and high-mass X-ray binaries (HMXBs) in the Galactic center. We searched for candidates by cross-correlating the 2MASS catalog with a deep Chandra catalog of X-ray point sources in the Radio Arches region. Following up with K-band spectroscopy, we found two massive stellar counterparts to CXOGC J174555.3-285126 and CXOGC J174617.0-285131, which we classify as a broad-lined WR star of sub-type WN6b and an O Ia supergiant, respectively. Their X-ray properties are most consistent with those of known colliding-wind binaries in the Galaxy and the Large Magellanic Cloud, although a scenario involving low-rate accretion onto a compact object is also possible. The O Ia star lies 4.4 pc in projection from the Quintuplet cluster, and has a radial velocity consistent with that of the Quintuplet, suggesting that this star might have escaped from the cluster. We also present the discovery of a B2 Ia supergiant, which we identified as a candidate massive star using 8 micron Spitzer maps of the Galactic center in a region near the known massive X-ray-emitting star CXOGC J174516.1-290315. We discuss the origin of these stars in the context of evolving stellar clusters in the Galactic center.
In this paper we study certain degenerations of the mirror curves, associated with Calabi-Yau threefolds $X_{N,M}$, and the effect of these degenerations on the topological string partition function of $X_{N,M}$. We show that when the mirror curve degenerates and become the union of the lower genus curves the corresponding partition function factorizes into pieces corresponding to the components of the degenerate mirror curve. Moreoever we show that using degeneration of a generalised mirror curve it is possible to obtain the partition function corresponding to $X_{N,M-1}$ from $X_{N,M}$.
According to a classical result due to Hudson, the Wigner function of a pure, continuous variable quantum state is non-negative if and only if the state is Gaussian. We have proven an analogous statement for finite-dimensional quantum systems. In this context, the role of Gaussian states is taken on by stabilizer states. The general results have been published in [D. Gross, J. Math. Phys. 47, 122107 (2006)]. For the case of systems of odd prime dimension, a greatly simplified proof can be employed which still exhibits the main ideas. The present paper gives a self-contained account of these methods.
We show that populations of high redshift galaxies grow more luminous as they grow in linear size. This is because the brightness per unit area has a distinct upper limit due to the self-regulating nature of star-formation. As a corollary, we show that the observed increase in characteristic luminosity of Lyman Break Galaxies (L*) with time can be explained by their increase in size, which scales as 1/H(z). In contrast, Lyman-alpha selected galaxies have a characteristic, constant, small size between redshift z=2.25 and 6.5. Coupled with a characteristic surface brightness, this can explain their non-evolving ultraviolet continuum luminosity function. This compact physical size seems to be a critical determining factor in whether a galaxy will show Lyman-alpha emission. We base these conclusions on new size measurements for a sample of about 170 Lyman-alpha selected galaxies with Hubble Space Telescope broad-band imaging, over the redshift range 2.25 < z < 6. We combine these with a similar number of Lyman-alpha selected galaxies with half-light radii from the literature, and derive surface brightnesses for the entire combined sample.
We show that specializations of the 4d $\mathcal{N}=2$ superconformal index labeled by an integer $N$ is given by $\textrm{Tr}\,{\cal M}^N$ where ${\cal M}$ is the Kontsevich-Soibelman monodromy operator for BPS states on the Coulomb branch. We provide evidence that the states enumerated by these limits of the index lead to a family of 2d chiral algebras $\mathcal{A}_{N}$. This generalizes the recent results for the $N=-1$ case which corresponds to the Schur limit of the superconformal index. We show that this specialization of the index leads to the same integrand as that of the elliptic genus of compactification of the superconformal theory on $S^2\times T^2$ where we turn on $\frac{1}{2} N$ units of $U(1)_r$ flux on $S^2$.
We argue that the measurement of open charm gives a unique opportunity to test the validity of pQCD-based and statistical models of nucleus-nucleus collisions at high energies. We show that various approaches used to estimate D-meson multiplicity in central Pb+Pb collisions at 158 A GeV give predictions which differ by more than a factor of 100. Finally we demonstrate that decisive experimental results concerning the open charm yield in A+A collisions can be obtained using data of the NA49 experiment at the CERN SPS.
Fix $d\in\{1,2\}$, we consider a $d$-dimensional stochastic wave equation driven by a Gaussian noise, which is temporally white and colored in space such that the spatial correlation function is integrable and satisfies Dalang's condition. In this setting, we provide quantitative central limit theorems for the spatial average of the solution over a Euclidean ball, as the radius of the ball diverges to infinity. We also establish functional central limit theorems. A fundamental ingredient in our analysis is the pointwise $L^p$-estimate for the Malliavin derivative of the solution, which is of independent interest. This paper is another addendum to the recent research line of averaging stochastic partial differential equations.
Neutrino oscillations are studied employing sources of low energy monoenergetic neutrinos following electron capture by the nucleus and measuring electron recoils. Since the neutrino energy is very low the oscillation length appearing in this electronic neutrino disappearance experiment can be so small that the full oscillation can take place inside the detector. Thus one may determine very accurately all the neutrino oscillation parameters. In particular one can measure or set a better limit on the unknown parameter theta13. One, however, has to pay the price that the expected counting rates are very small. Thus one needs a very intensive neutrino source and a large detector with as low as possible energy threshold and high energy and position resolution. Both spherical gaseous and cylindrical liquid detectors are studied. Different source candidates are considered
This paper presents a hand-written character recognition comparison and performance evaluation for robust and precise classification of different hand-written characters. The system utilizes advanced multilayer deep neural network by collecting features from raw pixel values. The hidden layers stack deep hierarchies of non-linear features since learning complex features from conventional neural networks is very challenging. Two state of the art deep learning architectures were used which includes Caffe AlexNet and GoogleNet models in NVIDIA DIGITS.The frameworks were trained and tested on two different datasets for incorporating diversity and complexity. One of them is the publicly available dataset i.e. Chars74K comprising of 7705 characters and has upper and lowercase English alphabets, along with numerical digits. While the other dataset created locally consists of 4320 characters. The local dataset consists of 62 classes and was created by 40 subjects. It also consists upper and lowercase English alphabets, along with numerical digits. The overall dataset is divided in the ratio of 80% for training and 20% for testing phase. The time required for training phase is approximately 90 minutes. For validation part, the results obtained were compared with the groundtruth. The accuracy level achieved with AlexNet was 77.77% and 88.89% with Google Net. The higher accuracy level of GoogleNet is due to its unique combination of inception modules, each including pooling, convolutions at various scales and concatenation procedures.
Classical communication schemes that exploit wave modulation are the basis of the information era. The transfer of information based on the quantum properties of photons revolutionized these modern communication techniques. Here we demonstrate that also matterwaves can be applied for information transfer and that their quantum nature provides a high level of security. Our technique allows transmitting a message by a non-trivial modulation of an electron matterwave in a biprism interferometer. The data is encoded by a Wien filter introducing a longitudinal shift between separated matterwave packets. The transmission receiver is a delay line detector performing a dynamic contrast analysis of the fringe pattern. Our method relies on the Aharonov-Bohm effect and has no light optical analog since it does not shift the phase of the electron interference. A passive eavesdropping attack will cause decoherence and terminating the data transfer. This is demonstrated by introducing a semiconducting surface that disturbs the quantum state by Coulomb interaction and reduces the contrast. We also present a key distribution protocol based on the quantum nature of the matterwaves that can reveal active eavesdropping.
Let p be a prime, k be a field of characteristic different from p containing a primitive p-th root of unity and N be the normalizer of the maximal torus in the projective linear group PGLn. We compute the exact value of the essential dimension ed(N;p) of N at p for every n.
Given a graphical degree sequence ${\bf d}=(d_1,\ldots, d_n)$, let $G(n, {\bf d})$ denote a uniformly random graph on vertex set $[n]$ where vertex $ i$ has degree $d_i$ for every $1\le i\le n$. We give upper and lower bounds on the joint probability of an arbitrary set of edges in $G(n,{\bf d})$. These upper and lower bounds are approximately what one would get in the configuration model, and thus the analysis in the configuration model can be translated directly to $G(n,{\bf d})$, without conditioning on that the configuration model produces a simple graph. Many existing results of $G(n,{\bf d})$ in the literature can be significantly improved with simpler proofs, by applying this new probabilistic tool. One example we give is about the chromatic number of $G(n,{\bf d})$.   In another application, we use these joint probabilities to study the connectivity of $G(n,{\bf d})$. When $\Delta^2=o(M)$ where $\Delta$ is the maximum component of ${\bf d}$, we fully characterise the connectivity phase transition of $G(n,{\bf d})$. We also give sufficient conditions for $G(n,{\bf d})$ being connected when $\Delta$ is unrestricted.