ShantanuT01/DACTYL-Pretraining huggingface dataset:
The dynamics of a flat Friedmann-Lema\^{i}tre-Robertson-Walker model minimally coupled to a massless scalar field has been intensively studied in the context of Loop Quantum Cosmology. This model admits an appropriate solvable representation, named sLQC. The form of the domain of the volume, the main observable to track the quantum evolution, is not straightforward in this solvable representation, and its explicit construction has been overlooked so far. In this work we find the explicit form of physical states belonging to the domain of the volume in sLQC. Specifically, given a physical state in the $v$-representation where the volume acts diagonally, we derive its form in the representation employed in sLQC, making explicit the connection between both representations at the physical level. To this end, we resort to the Wheeler-De Witt (WDW) approach, which shares the physical Hilbert space with sLQC when cast in an analog solvable representation, while being analytically solvable as well in the $v$-representation. Then the domain of the volume for the WDW approach provides that for sLQC. Furthermore, we address the question of semiclassicality in sLQC.
In this work, a hydrodynamic study of the di-hadron azimuthal correlations for the Au+Au collisions at 200 GeV is carried out. The correlations are evaluated using the ZYAM method for the centrality windows as well as the transverse momentum range in accordance with the existing data. Event-plane dependence of the correlation is obtained after the subtraction of contributions from the most dominant harmonic coefficients. In particular, the contribution from the triangular flow, $v_3$, is removed from the proper correlations following the procedure implemented by the STAR collaboration. The resultant structure observed in the correlations was sometimes attributed to the mini-jet dynamics, but the present calculations show that a pure hydrodynamic model gives a reasonable agreement with the main feature of the published data. A brief discussion on the physical content of the present findings is presented.
On February 17 2016, the IceCube real-time neutrino search identified, for the first time, three muon neutrino candidates arriving within 100 s of one another, consistent with coming from the same point in the sky. Such a triplet is expected once every 13.7 years as a random coincidence of background events. However, considering the lifetime of the follow-up program the probability of detecting at least one triplet from atmospheric background is 32%. Follow-up observatories were notified in order to search for an electromagnetic counterpart. Observations were obtained by Swift's X-ray telescope, by ASAS-SN, LCO and MASTER at optical wavelengths, and by VERITAS in the very-high-energy gamma-ray regime. Moreover, the Swift BAT serendipitously observed the location 100 s after the first neutrino was detected, and data from the Fermi LAT and HAWC observatory were analyzed. We present details of the neutrino triplet and the follow-up observations. No likely electromagnetic counterpart was detected, and we discuss the implications of these constraints on candidate neutrino sources such as gamma-ray bursts, core-collapse supernovae and active galactic nucleus flares. This study illustrates the potential of and challenges for future follow-up campaigns.
We combine the Shark semi-analytic model of galaxy formation with the ProSpect software tool for spectral energy distribution (SED) generation to study the multi-wavelength emission of galaxies from the far-ultraviolet (FUV) to the far-infrared (FIR) at $0\le z\le 10$. We produce a physical model for the attenuation of galaxies across cosmic time by combining a local Universe empirical relation to compute the dust mass of galaxies from their gas metallicity and mass, attenuation curves derived from radiative transfer calculations of galaxies in the EAGLE hydrodynamic simulation suite, and the properties of Shark galaxies. We are able to produce a wide range of galaxies, from the $z=8$ star-forming galaxies with almost no extinction, $z=2$ submillimeter galaxies, down to the normal star-forming and red sequence galaxies at $z=0$. Quantitatively, we find that Shark reproduces the observed (i) the $z=0$ FUV-to-FIR, (ii) $0\le z\le 3$ rest-frame $K$-band, and (iii) $0\le z\le 10$ rest-frame FUV luminosity functions, (iv) $z\le 8$ UV slopes, (v) the FUV-to-FIR number counts (including the widely disputed 850$\mu$m), (vi) redshift distribution of bright $850\mu$m galaxies and (vii) the integrated cosmic SED from $z=0$ to $z=1$ to an unprecedented level. This is achieved without the need to invoke changes in the stellar initial mass function, dust-to-metal mass ratio, or metal enrichment timescales. Our model predicts star formation in galaxy disks to dominate in the FUV-to-optical, while bulges dominate at the NIR at all redshifts. The FIR sees a strong evolution in which disks dominate at $z\le 1$ and starbursts (triggered by both galaxy mergers and disk instabilities, in an even mix) dominate at higher redshifts, even out to $z=10$.
We present simultaneous radio through sub-mm observations of the black hole X-ray binary (BHXB) V404 Cygni during the most active phase of its June 2015 outburst. Our $4$ hour long set of overlapping observations with the Very Large Array, the Sub-millimeter Array, and the James Clerk Maxwell Telescope (SCUBA-2), covers 8 different frequency bands (including the first detection of a BHXB jet at $666 \,{\rm GHz}/450\mu m$), providing an unprecedented multi-frequency view of the extraordinary flaring activity seen during this period of the outburst. In particular, we detect multiple rapidly evolving flares, which reach Jy-level fluxes across all of our frequency bands. With this rich data set we performed detailed MCMC modeling of the repeated flaring events. Our custom model adapts the van der Laan synchrotron bubble model to include twin bi-polar ejections, propagating away from the black hole at bulk relativistic velocities, along a jet axis that is inclined to the line of sight. The emission predicted by our model accounts for projection effects, relativistic beaming, and the geometric time delay between the approaching and receding ejecta in each ejection event. We find that a total of 8 bi-polar, discrete jet ejection events can reproduce the emission that we observe in all of our frequency bands remarkably well. With our best fit model, we provide detailed probes of jet speed, structure, energetics, and geometry. Our analysis demonstrates the paramount importance of the mm/sub-mm bands, which offer a unique, more detailed view of the jet than can be provided by radio frequencies alone.
We investigate the gravitational lensing properties of lines of sight containing multiple cluster-scale halos, motivated by their ability to lens very high-redshift (z ~ 10) sources into detectability. We control for the total mass along the line of sight, isolating the effects of distributing the mass among multiple halos and of varying the physical properties of the halos. Our results show that multiple-halo lines of sight can increase the magnified source-plane region compared to the single cluster lenses typically targeted for lensing studies, and thus are generally better fields for detecting very high-redshift sources. The configurations that result in optimal lensing cross sections benefit from interactions between the lens potentials of the halos when they overlap somewhat on the sky, creating regions of high magnification in the source plane not present when the halos are considered individually. The effect of these interactions on the lensing cross section can even be comparable to changing the total mass of the lens from 10^15 M_sun to 3x10^15 M_sun. The gain in lensing cross section increases as the mass is split into more halos, provided that the lens potentials are projected close enough to interact with each other. A nonzero projected halo angular separation, equal halo mass ratio, and high projected halo concentration are the best mass configurations, whereas projected halo ellipticity, halo triaxiality, and the relative orientations of the halos are less important. Such high mass, multiple-halo lines of sight exist in the SDSS.
We use a suite of simulated images based on Year 1 of the Dark Energy Survey to explore the impact of galaxy neighbours on shape measurement and shear cosmology. The hoopoe image simulations include realistic blending, galaxy positions, and spatial variations in depth and PSF properties. Using the im3shape maximum-likelihood shape measurement code, we identify four mechanisms by which neighbours can have a non-negligible influence on shear estimation. These effects, if ignored, would contribute a net multiplicative bias of $m \sim 0.03 - 0.09$ in the DES Y1 im3shape catalogue, though the precise impact will be dependent on both the measurement code and the selection cuts applied. This can be reduced to percentage level or less by removing objects with close neighbours, at a cost to the effective number density of galaxies $n_\mathrm{eff}$ of 30%. We use the cosmological inference pipeline of DES Y1 to explore the cosmological implications of neighbour bias and show that omitting blending from the calibration simulation for DES Y1 would bias the inferred clustering amplitude $S_8\equiv \sigma_8 (\Omega _\mathrm{m} /0.3)^{0.5}$ by $2 \sigma$ towards low values. Finally, we use the hoopoe simulations to test the effect of neighbour-induced spatial correlations in the multiplicative bias. We find the impact on the recovered $S_8$ of ignoring such correlations to be subdominant to statistical error at the current level of precision.
In this paper we address two problems in the BFKL Pomeron calculus in zero transverse dimensions: the summation of the Pomeron loops and the calculation of the processes of multiparticle generation. We introduce a new generating functional for these processes and obtain the evolution equation for it. We argue that in the kinematic range given by $ 1 \ll \ln(1/\as^2) \ll \as Y \ll \frac{1}{\as}$, we can reduce the Pomeron calculus to exchange of non-interacting Pomerons with the renormalized amplitude of their interaction with the target. Therefore, the summation of the Pomeron loops can be performed using Mueller, Patel, Salam and Iancu approximation.
The mixing properties (or sensitivity to initial conditions) and relaxation dynamics of the Henon map, together with the connection between these concepts, have been explored numerically at the edge of chaos. It is found that the results are consistent with those coming from one-dimensional dissipative maps. This constitutes the first verification of the scenario in two-dimensional cases and obviously reinforces the idea of weak mixing and weak chaos.   Keywords: Nonextensive thermostatistics, Henon map, dynamical systems
We build a simple, {\it top-down} model for the gas density and temperature profiles for galaxy clusters. The gas is assumed to be in hydrostatic equilibrium along with a component of non-thermal pressure taken from simulations and the gas fraction approaches the cosmic mean value only at the virial radius or beyond. The free parameters of the model are the slope and normalisation of the concentration-mass relation, the gas polytropic index, and slope and normalisation of the mass-temperature relation. These parameters can be fixed from X-Ray and lensing observations. We compare our gas pressure profiles to the recently proposed `Universal' pressure profile by \cite{Arnaud09} and find very good agreement. We find that the Sunyaev-Zel'dovich Effect (SZE) scaling relations between the integrated SZE flux, $Y$, the cluster gas temperature, $T_{\rm sl}$, the cluster mass, $M_{\rm tot}$, and the gas mass, $M_{\rm gas}$ are in excellent agreement with the recently observed $r_{2500}$ SZE scaling relations by \cite{Bonamente08} and $r_{500}$ relation by \cite{Arnaud09}. The gas mass fraction increases with cluster mass and is given by $f_{\rm gas}(r_{500}) = 0.1324 + 0.0284 \,\rm{log}\, (\frac{M_{500}}{10^{15}h^{-1}M_\odot})$. This is within $10%$ of observed $f_{\rm gas}(r_{500})$. The consistency between the global properties of clusters detected in X-Rays and in SZE shows that we are looking at a common population of clusters as a whole, and there is no deficit of SZE flux relative to expectations from \xr scaling properties. Thus, it makes it easier to compare and cross-calibrate clusters from upcoming \xr and SZE surveys.
Gravitational perturbations in a Kerr black hole background can not be decomposed into simple tensor harmonics in the time domain. Here, we make the mode decomposition only in the azimuthal direction and discuss the resulting (2+1)-dimensional Klein-Gordon differential equation for scalar perturbations with a two dimensional Dirac's $\delta$-function as a source representing a point particle orbiting a much larger black hole. To make this equation amenable for numerical integrations we explicitly remove analytically the singular behavior of the source and compute a global effective source for the corresponding waveform.
We analyze the excess noise in the framework of the conventional quantum theory of laser-like systems. Our calculation is conceptually simple and our result also shows a correction to the semi-classical result derived earlier.
We give asymptotic spectral results for Gram matrices of the form $ n^{-1}\mathcal{X}_n \mathcal{X}_n^T$ where the entries of $\mathcal{X}_n$ are dependent across both rows and columns. More precisely, they consist of short or long range dependent random variables having moments of second order and that are functionals of an absolutely regular sequence. We also give a concentration inequality of the Stieltjes transform and we prove that, under an arithmetical decay condition on the $\beta$-mixing coefficients, it is almost surely concentrated around its expectation. Applications to examples of positive recurrent Markov chains and dynamical systems are also given.
We present first results from the KMOS Redshift One Spectroscopic Survey (KROSS), an ongoing large kinematical survey of a thousand, z~1 star forming galaxies, with VLT KMOS. Out of the targeted galaxies (~500 so far), we detect and spatially resolve Ha emission in ~90% and 77% of the sample respectively. Based on the integrated Ha flux measurements and the spatially resolved maps we derive a median star formation rate (SFR) of ~7.0 Msun/yr and a median physical size of <r$_{\rm e}$> = 5.1kpc. We combine the inferred SFRs and effective radii measurements to derive the star formation surface densities ({\Sigma}SFR) and present a "resolved" version of the star formation main sequence (MS) that appears to hold at sub-galactic scales, with similar slope and scatter as the one inferred from galaxy integrated properties. Our data also yield a trend between {\Sigma}SFR and {\Delta}(sSFR) (distance from the MS) suggesting that galaxies with higher sSFR are characterised by denser star formation activity. Similarly, we find evidence for an anti-correlation between the gas phase metallicity (Z) and the {\Delta}(sSFR), suggesting a 0.2dex variation in the metal content of galaxies within the MS and significantly lower metallicities for galaxies above it. The origin of the observed trends between {\Sigma}SFR - {\Sigma}(sSFR) and Z - {\Delta}(sSFR) could be driven by an interplay between variations of the gas fraction or the star formation efficiency of the galaxies along and off the MS. To address this, follow-up observations of the our sample that will allow gas mass estimates are necessary.
With the recent substantial growth of media such as YouTube, a considerable number of instructional videos covering a wide variety of tasks are available online. Therefore, online instructional videos have become a rich resource for humans to learn everyday skills. In order to improve the effectiveness of the learning with instructional video, observation and evaluation of the activity are required. However, it is difficult to observe and evaluate every activity steps by expert. In this study, a novel deep learning framework which targets human activity evaluation for learning from instructional video has been proposed. In order to deal with the inherent variability of activities, we propose to model activity as a structured process. First, action units are encoded from dense trajectories with LSTM network. The variable-length action unit features are then evaluated by a Siamese LSTM network. By the comparative experiments on public dataset, the effectiveness of the proposed method has been demonstrated.
Whereas single- and two-photon wave packets are usually treated as pure states, in practice they will be mixed. We study how entanglement created with mixed photon wave packets is degraded. We find in particular that the entanglement of a delocalized single-photon state of the electro-magnetic field is determined simply by its purity. We also discuss entanglement for two-photon mixed states, as well as the influence of a vacuum component.
The regime of exponentially fast expansion in 5D cosmological models was investigated. Many limit cases was also studied. It was shown that there is a possibility to particle creation in a static 4D spacetime if it embedded in an bulk with an expanding extra-dimension y. It was also shown that many physical quantities like the particle number density, vacuum pressure and energy density has its behavior governed by the expansion rate parameters ({\alpha},{\beta}) that control the inflation process. These parameters also limit the field modes that can be created in a given model. The case with modes with ky = 0 was investigated and was shown that only massive modes are allowed. These modes are taken to be confined in the 4D spacetime. From the 5D Einstein's field equation, where the only sources considered comes from the vacuum fluctuation, was determined the presence of a given cosmological time ({\eta}) that makes the 5D cosmological constant vanish in some models and behave like a limit time that governs a transition from an expanding cosmological model to a completely static model.
We calculate the temperature and polarization patterns generated in anisotropic cosmological models drawn from the Bianchi classification. We show that localized features in the temperature pattern, perhaps similar to the cold spot observed in the Wilkinson Microwave Anisotropy Probe (WMAP) data, can be generated in models with negative spatial curvature, i.e. Bianchi types V and VII$_{h}$. Both these models also generate coherent polarization patterns. In Bianchi VII$_h$, however, rotation of the polarization angle as light propagates along geodesics can convert E modes into B modes but in Bianchi V this is not necessarily the case. It is in principle possible, therefore, to generate localized temperature features without violating existing observational constraints on the odd-parity component of the polarization of the cosmic microwave background.
We demonstrate theoretically that the spin polarization of current can be electrically amplified within nonmagnetic semiconductors by exploiting the fact the spin current, compared to the charge current, is weakly perturbed by electric driving forces. As a specific example, we consider a T-shaped current branching geometry made entirely of a nonmagnetic semiconductor, where the current is injected into one of the branches (input branch) and splits into the other two branches (output branches). We show that when the input current has a moderate spin polarization, the spin polarization in one of the output branches can be higher than the spin polarization in the input branch and may reach 100% when the relative magnitudes of current-driving electric fields in the two output branches are properly tuned. The proposed amplification scheme does not use ferromagnets or magnetic fields, and does not require low temperature operation, providing an efficient way to generate a highly spin polarized current in nonmagnetic semiconductors at room temperature.
By using the transfer matrix approach, we investigate the asymptotic behavior of the entropy of flexible chains with $M$ monomers each placed on stripes. In the limit of high density of monomers, we study the behavior of the entropy as a function of the density of monomers and the width of the stripe, inspired by recent analytical studies of this problem for the particular case of dimers (M=2). We obtain the entropy in the asymptotic regime of high densities for chains with $M=2,..,9$ monomers, as well as for the special case of polymers, where $M\to\infty$, and find that the results show a regular behavior similar to the one found analytically for dimers. We also verify that in the low-density limit the mean-field expression for the entropy is followed by the results from our transfer matrix calculations.
This note presents basic restrictions on the topology "general" Lagrangian surfaces of hyper-K\"ahler $4$-folds and a remark on the interaction of a Lagrangian subvariety with a Lagrangian fibration of the associated hyper-K\"ahler variety.
In this paper we present near-infrared K-band imaging of a sample of ultra-steep spectrum (USS) radio sources selected at 74 MHz. The dual selection criteria of low frequency and USS means that we should be sensitive to the highest redshift (z > 5) radio galaxies. We have obtained $K-$band magnitudes for all of the objects in our sample of 26 and discuss the properties of each.   There is a pronounced bias in this sample towards fainter magnitudes and thus higher redshifts when compared to complete unfiltered samples such as 7CRS (Willott et al. 2002), implying that the steep-spectrum technique is still viable at 74 MHz. However, there are more bright (K < 17) sources in the 74 MHz sample than in a similar sample selected at 151 MHz, namely 6C*. This is principally due to the additional selection criterion of a small angular size for the radio sources in 6C*, four of the six sources in the 74 MHz USS sample with K < 17 have angular sizes > 15 arcsec (the angular size cutoff of 6C*).   We find that the distribution of K-band magnitudes from a sample selected at 74 MHz is statistically indistinguishable from the 6C* sample, when similar angular size filtering is applied to the 74 MHz sample.
Here we review and extend central limit theorems for highly chaotic but deterministic semi-dynamical discrete time systems. We then apply these results show how Brownian motion-like results are recovered, and how an Ornstein-Uhlenbeck process results within a totally deterministic framework. These results illustrate that the contamination of experimental data by "noise" may, under certain circumstances, be alternately interpreted as the signature of an underlying chaotic process.
All possible interactions of a point particle with background electromagnetic, gravitational and higher-spin fields is considered in the two-time physics worldline formalism in (d,2) dimensions. This system has a counterpart in a recent formulation of two-time physics in non-commutative field theory with local Sp(2) symmetry. In either the worldline or field theory formulation, a general Sp(2) algebraic constraint governs the interactions, and determines equations that the background fields of any spin must obey. The constraints are solved in the classical worldline formalism (h-bar=0 limit) as well as in the field theory formalism (all powers of h-bar). The solution in both cases coincide for a certain 2T to 1T holographic image which describes a relativistic particle interacting with background fields of any spin in (d-1,1) dimensions. Two disconnected branches of solutions exist, which seem to have a correspondence as massless states in string theory, one containing low spins in the zero Regge slope limit, and the other containing high spins in the infinite Regge slope limit.