ShantanuT01/DACTYL-Pretraining huggingface dataset:
New data from HERA experiment on deep inelastic scattering have been used to parametrize nucleon and Pomeron structure functions. Within the Gribov theory, the parameterizations were employed to calculate gluon shadowing for various heavy ions. The latter was compared with predictions from other models. Calculations of multiplicity reduction due to gluon shadowing for d+Au collisions at forward rapidities at $\sqrt{s}$=200 GeV are in good agreement with BRAHMS data on the nuclear modification factor.
After a summary of the basic three neutrino oscillation formalism we review briefly our present empirical knowledge of the oscillation parameters and conclude that the 2-neutrinos model is adequate to describe the survival probability of the electronic neutrino P(nue->nue). Then we proceed to the evaluation of P(nue->nue) relative to the antineutrinos emitted by the nuclear power stations presently in operation along the the Rhone valley. We assume that a detector has been installed in a existing cavity located under the Mont Ventoux at a depth equivalent to 1500 m of water. We show that such an experiment would provide the opportunity to observe neutrinos near the oscillation absolute minimum. We end by a rough estimate of the counting rate.
In this work we study the effect of the symmetry energy on several properties of neutron stars. First, we discuss its effect on the density, proton fraction and pressure of the neutron star crust-core transition. We show that whereas the first two quantities present a clear correlation with the slope parameter $L$ of the symmetry energy, no satisfactory correlation is seen between the transition pressure and $L$. However, a linear combination of the slope and curvature parameters at $\rho=0.1$ fm$^{-3}$ is well correlated with the transition pressure. In the second part we analyze the effect of the symmetry energy on the pasta phase. It is shown that the size of the pasta clusters, number of nucleons and the cluster proton fraction depend on the density dependence of the symmetry energy: a small $L$ gives rise to larger clusters. The influence of the equation of state at subsaturation densities on the extension of the inner crust of the neutron star is also discussed. Finally, the effect of the effect of the density dependence of the symmetry energy on the strangeness content of neutron stars is studied in the last part of the work. It is found that charged (neutral) hyperons appear at smaller (larger) densities for smaller values of the slope parameter $L$. A linear correlation between the radius and the strangeness content of a star with a fixed mass is also found.
We consider point process convergence for sequences of iid random walks. The objective is to derive asymptotic theory for the largest extremes of these random walks. We show convergence of the maximum random walk to the Gumbel or the Fr\'echet distributions. The proofs heavily depend on precise large deviation results for sums of independent random variables with a finite moment generating function or with a subexponential distribution.
In this work we show how to construct the one-loop vacuum polarization for light-front QED$_{4}$ in the framework of the perturbative causal theory. Usually, in the canonical approach, it is considered for the fermionic propagator the so-called instantaneous term, but it is known in literature that this term is controversial because it can be omitted by computational reasons; for instance, by compensation or vanishing by dimensional regularization. In this work we propose a solution to this paradox. First, in the perturbative causal theory, it is shown that the fermionic propagator does not have instantaneous terms, and with this propagator we calculate the one-loop vacuum polarization, from the calculation it follows the same result as obtained by the standard approach, but without reclaiming any extra assumptions. Moreover, since the perturbative causal theory is defined in the distributional framework, we can also show the reason behind we obtaining the same result whether we consider or not the instantaneous fermionic propagator term.
Stellar activity is ubiquitously encountered in M dwarfs and often characterised by the H$\alpha$ line. In the most active M dwarfs, H$\alpha$ is found in emission, sometimes with a complex line profile. Previous studies have reported extended wings and asymmetries in the H$\alpha$ line during flares. We used a total of 473 high-resolution spectra of 28 active M dwarfs obtained by the CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) spectrograph to study the occurrence of broadened and asymmetric H$\alpha$ line profiles and their association with flares, and examine possible physical explanations. We detected a total of 41 flares and 67 broad, potentially asymmetric, wings in H$\alpha$. The broadened H$\alpha$ lines display a variety of profiles with symmetric cases and both red and blue asymmetries. Although some of these line profiles are found during flares, the majority are at least not obviously associated with flaring. We propose a mechanism similar to coronal rain or chromospheric downward condensations as a cause for the observed red asymmetries; the symmetric cases may also be caused by Stark broadening. We suggest that blue asymmetries are associated with rising material, and our results are consistent with a prevalence of blue asymmetries during the flare onset. Besides the H$\alpha$ asymmetries, we find some cases of additional line asymmetries in \ion{He}{i} D$_{3}$, \ion{Na}{i}~D lines, and the \ion{He}{i} line at 10830\,\AA\, taken all simultaneously thanks to the large wavelength coverage of CARMENES. Our study shows that asymmetric H$\alpha$ lines are a rather common phenomenon in M~dwarfs and need to be studied in more detail to obtain a better understanding of the atmospheric dynamics in these objects.
We analyse the possible D-brane configurations in an AdS_3xS^3xS^3xS^1 background with a NS-NS B field, by using the boundary state formalism. We study their geometry and we determine the fraction of spacetime supersymmetry preserved by these solutions.
The gamma-ray binary system LS I +61 303 was studied in great detail in VHE gamma-rays in the last years by the MAGIC telescope. The VHE emission of the system exhibited a prominent periodic outburst in the orbital phases 0.6-0.7 between September 2005 to January 2008. In Fall 2008 the Fermi collaboration reported as well periodic emission in the MeV to GeV energy range, but with a shifted outburst in the phases 0.35-0.45. MAGIC observed again LS I+61 303 in 2009 with the twice more sensitive stereo mode to allow for detailed correlation studies between the VHE gamma-ray and Fermi/LAT energy band. Here we present our new results, which show a significant reduction in the VHE gamma-ray flux in the phase of the periodic outburst by almost one order of magnitude compared to our previous measurements. Furthermore, the 0.1-phase averaged light curve shows no significant outburst, but a rather constant flux. Here we will discuss the implications of our results for future gamma-ray studies of LS I +61 303.
The Poisson algebra of the Lax matrix associated with the Pohlmeyer reduction of the AdS_5 x S^5 superstring is computed from first principles. The resulting non-ultralocality is mild, which enables to write down a corresponding lattice Poisson algebra.
Compressible models extend the domain of simulable systems in quantum computers, but little is known about their precise limits of applicability. Using the theory of compressible matchgate circuits, we identify a class of quadratic fermionic Hamiltonians that can be simulated in compressed space. In particular, for systems of $n$ orbitals encoded to 2-local qubit models with nearest neighbour interactions, the ground state energy can be evaluated with $O\left(\log n\right)$ sets of measurements, independently of the number of dimensions in which the $n$ sites are arranged. We also provide an expressible circuit ansatz in a logarithmic number of qubits for finding the compressed ground state with a variational quantum eigensolver. From the complexity analysis of the compressed circuits, we find a regime of quantum supremacy for sampling compressed Gaussian fermionic models.
A nonrelativistic particle released from rest at the edge of a ball of uniform charge density or mass density oscillates with simple harmonic motion. We consider the relativistic generalizations of these situations where the particle can attain speeds arbitrarily close to the speed of light; generalizing the electrostatic and gravitational cases requires special and general relativity, respectively. We find exact closed-form relations between the position, proper time, and coordinate time in both cases, and find that they are no longer harmonic, with oscillation periods that depend on the amplitude. In the highly relativistic limit of both cases, the particle spends almost all of its proper time near the turning points, but almost all of the coordinate time moving through the bulk of the ball. Buchdahl's theorem imposes nontrivial constraints on the general-relativistic case, as a ball of given density can only attain a finite maximum radius before collapsing into a black hole. This article is intended to be pedagogical, and should be accessible to those who have taken an undergraduate course in general relativity.
A campaign is described, open to participation by interested AAVSO members, of follow-up observations for newly-discovered Cepheid variables in undersampled and obscured regions of the Galaxy. A primary objective being to use these supergiants to clarify the Galaxy's spiral nature. Preliminary multiband photometric observations are presented for three Cepheids discovered beyond the obscuring dust between the Cygnus & Aquila Rifts (40 \le l \le 50 degrees), a region reputedly tied to a segment of the Sagittarius-Carina arm which appears to cease unexpectedly. The data confirm the existence of exceptional extinction along the line of sight at upwards of A_V~6 magnitudes (d~2 kpc, l~47 degrees), however, the noted paucity of optical spiral tracers in the region does not arise solely from incompleteness owing to extinction. A hybrid spiral map of the Galaxy comprised of classical Cepheids, young open clusters & H II regions, and molecular clouds, presents a consistent picture of the Milky Way and confirms that the three Cepheids do not populate the main portion of the Sagittarius-Carina arm, which does not emanate locally from this region. The Sagitarrius-Carina arm, along with other distinct spiral features, are found to deviate from the canonical logarithmic spiral pattern. Revised parameters are also issued for the Cepheid BY Cas, and it is identified on the spiral map as lying mainly in the foreground to young associations in Cassiopeia. A Fourier analysis of BY Cas' light-curve implies overtone pulsation, and the Cepheid is probably unassociated with the open cluster NGC 663 since the distances, ages, and radial velocities do not match.
We consider the Poisson hail model introduced by Baccelli and Foss. We give a power law condition for the tails (spatial and temporal) of the distribution of jobs to ensure stability as the rate parameter $\lambda $ tends to zero. We then show that in a weak sense it is optimal.
In this paper we study a nonlinear reaction-diffusion system which models an infectious disease caused by bacteria such as those for cholera. One of the significant features in this model is that a certain portion of the recovered human hosts may lose a lifetime immunity and could be infected again. Another important feature in the model is that the mobility for each species is allowed to be dependent upon both the location and time. With the whole population assumed to be susceptible with the bacteria, the model is a strongly coupled nonlinear reaction-diffusion system. We prove that the nonlinear system has a unique solution globally in any space dimension under some natural conditions on the model parameters and the given data. Moreover, the long-time behavior and stability analysis for the solutions are carried out rigorously. In particular, we characterize the precise conditions on variable parameters about the stability or instability of all steady-state solutions. These new results provide the answers to several open questions raised in the literature.
We study random lozenge tilings of a certain shape in the plane called the Novak half-hexagon, and compute the correlation functions for this process. This model was introduced by Nordenstam and Young (2011) and has many intriguing similarities with a more well-studied model, domino tilings of the Aztec diamond. The most difficult step in the present paper is to compute the inverse of the matrix whose (i,j) entry is the binomial coefficient C(A, B_j - i) for indeterminate variables A and B_1, ..., B_n.
The well-known Gilbert-Shannon-Reeds model for riffle shuffles assumes that the cards are initially cut 'about in half' and then riffled together. We analyze a natural variant where the initial cut is biased. Extending results of Fulman (1998), we show a sharp cutoff in separation and L-infinity distances. This analysis is possible due to the close connection between shuffling and quasisymmetric functions along with some complex analysis of a generating function.
We propose a new framework for conditional image synthesis from semantic layouts of any precision levels, ranging from pure text to a 2D semantic canvas with precise shapes. More specifically, the input layout consists of one or more semantic regions with free-form text descriptions and adjustable precision levels, which can be set based on the desired controllability. The framework naturally reduces to text-to-image (T2I) at the lowest level with no shape information, and it becomes segmentation-to-image (S2I) at the highest level. By supporting the levels in-between, our framework is flexible in assisting users of different drawing expertise and at different stages of their creative workflow. We introduce several novel techniques to address the challenges coming with this new setup, including a pipeline for collecting training data; a precision-encoded mask pyramid and a text feature map representation to jointly encode precision level, semantics, and composition information; and a multi-scale guided diffusion model to synthesize images. To evaluate the proposed method, we collect a test dataset containing user-drawn layouts with diverse scenes and styles. Experimental results show that the proposed method can generate high-quality images following the layout at given precision, and compares favorably against existing methods. Project page \url{https://zengxianyu.github.io/scenec/}
We prove that for each $k\ge0$, the probability that a root vertex in a random planar graph has degree $k$ tends to a computable constant $d_k$, so that the expected number of vertices of degree $k$ is asymptotically $d_k n$, and moreover that $\sum_k d_k =1$.   The proof uses the tools developed by Gimenez and Noy in their solution to the problem of the asymptotic enumeration of planar graphs, and is based on a detailed analysis of the generating functions involved in counting planar graphs. However, in order to keep track of the degree of the root, new technical difficulties arise. We obtain explicit, although quite involved expressions, for the coefficients in the singular expansions of the generating functions of interest, which allow us to use transfer theorems in order to get an explicit expression for the probability generating function $p(w)=\sum_k d_k w^k$. From this we can compute the $d_k$ to any degree of accuracy, and derive the asymptotic estimate $d_k \sim c\cdot k^{-1/2} q^k$ for large values of $k$, where $q \approx 0.67$ is a constant defined analytically.
It was recently demonstrated in [Chaudhury et al.,Non-Local Euclidean Medians,2012] that the denoising performance of Non-Local Means (NLM) can be improved at large noise levels by replacing the mean by the robust Euclidean median. Numerical experiments on synthetic and natural images showed that the latter consistently performed better than NLM beyond a certain noise level, and significantly so for images with sharp edges. The Euclidean mean and median can be put into a common regression (on the patch space) framework, in which the l_2 norm of the residuals is considered in the former, while the l_1 norm is considered in the latter. The natural question then is what happens if we consider l_p (0<p<1) regression? We investigate this possibility in this paper.
There is accumulating evidence that at least a fraction of binary neutron star mergers result in rapidly spinning magnetars, with subrelativistic neutron-rich ejecta as massive as a small fraction of solar mass. The ejecta could be heated continuously by the Poynting flux emanated from the central magnetars. Such Poynting flux could become lepton-dominated so that a reverse shock develops. It was demonstrated that such a picture is capable of accounting for the optical transient PTF11agg (Wang & Dai 2013b). In this paper we investigate the X-ray and ultraviolet (UV) radiation as well as the optical and radio radiation studied by Wang & Dai (2013b). UV emission is particularly important because it has the right energy to ionize the hot ejecta at times $t\lesssim 600$ s. It is thought that the ejecta of binary neutron star mergers are a remarkably pure sample of r-process material, about which our understanding is still incomplete. In this paper we evaluate the possibility of observationally determining the bound-bound and bound-free opacities of the r-process material by timing the X-ray, UV, and optical radiation. It is found that these timings depend on the opacities weakly and therefore only loose constraints on the opacities can be obtained.
The linear programming (LP) bound of Delsarte can be applied to several problems in various branches of mathematics. We describe a general Fourier analytic method to get a slight improvement on this bound. We then apply our method to the problem of mutually unbiased bases (MUBs) to prove that the Fourier family $F(a,b)$ in dimension 6 cannot be extended to a full system of MUBs.
We establish several surjectivity theorems regarding the Galois groups of small iterates of $\phi_c(x)=x^2+c$ for $c\in\mathbb{Q}$. To do this, we use explicit techniques from the theory of rational points on curves, including the method of Chabauty-Coleman and the Mordell-Weil sieve. For example, we succeed in finding all rational points on a hyperelliptic curve of genus $7$, with rank $5$ Jacobian, whose points parametrize quadratic polynomials with a "newly small" Galois group at the fifth stage of iteration.
We study effective versions of unlikely intersections of images of torsion points of elliptic curves on the projective line.
The wave-particle duality of light has led to two different encodings for optical quantum information processing. Several approaches have emerged based either on particle-like discrete-variable states, e.g. finite-dimensional quantum systems, or on wave-like continuous-variable states, e.g. infinite-dimensional systems. Here, we demonstrate the first measurement-induced generation of entanglement between optical qubits of these different types, located at distant places and connected by a lossy channel. Such hybrid entanglement, which is a key resource for a variety of recently proposed schemes, including quantum cryptography and computing, enables to convert information from one Hilbert space to the other via teleportation and therefore connect remote quantum processors based upon different encodings. Beyond its fundamental significance for the exploration of entanglement and its possible instantiations, our optical circuit opens the promises for heterogeneous network implementations, where discrete and continuous-variable operations and techniques can be efficiently combined.
We present a study on the environments of the SDSS galaxies divided into fine classes based on their morphology, colour and spectral features. The SDSS galaxies are classified into early-type and late-type; red and blue; passive, HII, Seyfert and LINER, which returns a total of 16 fine classes of galaxies. We estimate the local number density, target-excluded local luminosity density, local colour, close pair fraction and the luminosity and colour of the brightest neighbour, which are compared between the fine classes comprehensively. The morphology-colour class of galaxies strongly depends on the local density, with the approximate order of high-density preference: red early-type galaxies (REGs) -- red late-type galaxies (RLGs) -- blue early-type galaxies (BEGs) -- blue late-type galaxies (BLGs). We find that high-density environments (like cluster environments) seem to suppress AGN activity. The pair fraction of HII REGs does not show statistically significant difference from that of passive REGs, while the pair fraction of HII BLGs is smaller than that of non-HII BLGs. HII BLGs show obvious double (red + blue) peaks in the distribution of the brightest neighbour colour, while red galaxies show a single red peak. The brightest neighbours of Seyfert BLGs tend to be blue, while those of LINER BLGs tend to be red, which implies that the difference between Seyfert and LINER may be related to the pair interaction. Other various environments of the fine classes are investigated, and their implication on galaxy evolution is discussed.
The $\mathscr{P}$-position sets of some combinatorial games have special combinatorial structures. For example, the $\mathscr{P}$-position set of the hexad game, first investigated by Conway and Ryba, is the block set of the Steiner system $S(5, 6, 12)$ in the shuffle numbering, $\mathcal{D}_{\text{sh}}$. There were, however, few known games related to Steiner systems like the hexad game. For a given Steiner system, we construct a game whose $\mathscr{P}$-position set is its block set.   By using constructed games, we obtain the following two results. First, we characterize $\mathcal{D}_{\text{sh}}$ among the 5040 isomorphic $S(5, 6, 12)$ with point set $\{0, 1, \ldots, 11\}$. For each $S(5, 6, 12)$, our construction produces a game whose $\mathscr{P}$-position set is its block set. From $\mathcal{D}_{\text{sh}}$, we obtain the hexad game, and this game is characterized as a unique game with the minimum number of positions among the obtained 5040 games. Second, we characterize projective Steiner triple systems by using game distributions. Here, the game distribution of a Steiner system $\mathcal{D}$ is the frequency distribution of the numbers of positions in games obtained from Steiner systems isomorphic to $\mathcal{D}$. We find that the game distribution of an $S(t, t + 1, v)$ can be decomposed into symmetric components and that a Steiner triple system is projective if and only if its game distribution has a unique symmetric component.
Extensive air showers (EAS) have been known for over 30 years to emit pulses of radio emission at frequencies from a few to a few hundred MHz, an effect that offers great opportunities for the study of EAS with the next generation of "software radio interferometers" such as LOFAR and LOPES. The details of the emission mechanism, however, remain rather uncertain to date. Following past suggestions that the bulk of the emission is of geomagnetic origin, we model the radio pulses as "coherent geosynchrotron radiation" arising from the deflection of electrons and positrons in the earth's magnetic field. We analytically develop our model in a step-by-step procedure to disentangle the coherence effects arising from different scales present in the shower structure and infer which shower characteristics govern the frequency spectrum and radial dependence of the emission. The effect is unavoidable and our predictions are in good agreement with the available experimental data within their large margins of error.