ShantanuT01/DACTYL-Pretraining huggingface dataset:
We describe the zero-temperature phase diagram of a model of bosons, occupying sites of a linear chain, which obey a hard-exclusion constraint: any two nearest-neighbor sites may have at most one boson. A special case of our model was recently proposed as a description of a ``tilted'' Mott insulator of atoms trapped in an optical lattice. Our quantum Hamiltonian is shown to generate the transfer matrix of Baxter's hard-square model. Aided by exact solutions of a number of special cases, and by numerical studies, we obtain a phase diagram containing states with long-range density-wave order with period 2 and period 3, and also a floating incommensurate phase. Critical theories for the various quantum phase transitions are presented. As a byproduct, we show how to compute the Luttinger parameter in integrable theories with hard-exclusion constraints.
In this paper, we extend our previous study \cite{DelPopolo2021} on the Lemaitre-Tolman (LT) model showing how the prediction of the model changes when the equation of state parameter ($w$) of dark energy is modified. In the previous study, it was considered that dark energy was merely constituted by the cosmological constant. In this paper, as in the previous study, we also took into account the effect of angular momentum and dynamical friction ($J\eta$ LT model) that modifies the evolution of a perturbation, initially moving with the Hubble flow. As a first step, solving the equation of motion, we calculated the relationship between mass, $M$, and the turn-around radius, $R_0$. If one knows the value of the turn-around radius $R_0$, it is possible to obtain the mass of the studied objects. As a second step, we build up, as in the previous paper, a relationship between the velocity, $v$, and radius, $R$. The relation was fitted to data of groups and clusters. Since the relationship $v-R$ depends on the Hubble constant and the mass of the object, we obtained optimized values of the two parameters of the objects studied. The mass decreases of a factor of maximum 25\% comparing the $J\eta$ LT results (for which $w=-1$) and the case $w=-1/3$, while the Hubble constant increases going from $w=-1$ to $w=-1/3$. Finally, the obtained values of the mass, $M$, and $R_0$ of the studied objects can put constraints to the dark energy equation of state parameter, $w$.
Metallicity is one of four free parameters typically considered when fitting isochrones to the cluster sequence. Unfortunately, this parameter is often ignored or assumed to be solar in most papers. Hence an unknown bias is introduced in the estimation of the other three cluster parameters (age, reddening and distance). Furthermore, studying the metallicity of open clusters allows us not only to derive the Galactic abundance gradient on a global scale, but also to trace the local solar environment in more detail. In a series of three papers, we investigate the current status of published metallicities for open clusters from widely different photometric and spectroscopic methods. A detailed comparison of the results allows us to establish more reliable photometric calibrations and corrections for isochrone fitting techniques. Well established databases such as WEBDA help us to perform a homogeneous analysis of available measurements for a significant number of open clusters. The literature was searched for [Fe/H] estimates on the basis of photometric calibrations in any available filter system. On the basis of results published by Tadross, we demonstrate the caveats of the calibration choice and its possible impact. In total, we find 406 individual metallicity values for 188 open clusters within 64 publications. The values were, finally, unweightedly averaged. Our final sample includes [Fe/H] values for 188 open clusters. Tracing the solar environment within 4000x4000 pc**2 we identify a patchy metallicity distribution as an extension to the Local Bubble that significantly influences the estimation of the Galactic metallicity gradient, even on a global scale. In addition, further investigations of more distant open clusters are clearly needed to obtain a more profound picture at Galactocentric distances beyond 10 000 pc.
The room temperature ``metallic'' properties of the quasi-one-dimensional charge density wave system (TaSe4)2I differ markedly from those expected of either a Fermi or a Luttinger Liquid. We discuss evidence for the simplest possible explanation of the observed behavior of (TaSe4)2I in its conducting phase - namely the existence of large quasi-static fluctuations of structural order, which however remain of finite extent above the charge density wave transition temperature. These fluctuations produce a pseudogap in the density of states. We compute the temperature dependence of the optical and DC conductivities of (TaSe4)2I in its conducting phase, the nature of its core hole spectra, and the NMR relaxation rate. Predictions for these quantities are made on the basis of a Lee, Rice and Anderson model. This model represents the simplest theory of a pseudogap, and gives satisfactory agreement with experiment in the cases where comparisons can be made. In contrast, the predictions of a strongly correlated (Luttinger Liquid) model appear to to contradict the data. The chief remaining discrepancy is that the gap appearing in transport quantities is less than that observed in photoemission. We discuss some possibilities for resolving this issue.
New plasma mechanism for the generation of toroidal magnetic field in the magnetosphere of Crab pulsar is presented. It is based on the development of two-stream instability in the relativistic electron-positron plasma of the pulsar magnetosphere. In particular, pulsar magnetosphere relativistic plasma is penetrated by ultrarelativistic electron beam and two-stream instability develops, as a result of which toroidal magnetic field is generated.
In order to obtain robust cosmological constraints from Type Ia supernova (SN Ia) data, we have applied Markov Chain Monte Carlo (MCMC) to SN Ia lightcurve fitting. We develop a method for sampling the resultant probability density distributions (pdf) of the SN Ia lightcuve parameters in the MCMC likelihood analysis to constrain cosmological parameters, and validate it using simulated data sets. Applying this method to the Joint Lightcurve Analysis (JLA) data set of SNe Ia, we find that sampling the SN Ia lightcurve parameter pdf's leads to cosmological parameters closer to that of a flat Universe with a cosmological constant, compared to the usual practice of using only the best fit values of the SN Ia lightcurve parameters. Our method will be useful in the use of SN Ia data for precision cosmology.
We study the conductance of an interconnect between two graphene leads formed by a single-atom carbon chain. Its dependence on the chemical potential and the number of atoms in the chain is qualitatively different from that in the case of normal metal leads. Electron transport proceeds via narrow resonant states in the wire. The latter arise due to strong reflection at the junctions between the chain and the leads, which is caused by the small density of states in the leads at low energy. The energy dependence of the transmission coefficient near resonance is asymmetric and acquires a universal form at small energies. We find that in the case of leads with the zigzag edges the dispersion of the edge states has a significant effect on the device conductance.
New and existing photometry for the G0 Ia supergiant HD 18391 is analyzed in order to confirm the nature of the variablity previously detected in the star, which lies off the hot edge of the Cepheid instability strip. Small-amplitude variability at a level of \Delta V = 0.016+-0.002 is indicated, with a period of P=123.04+-0.06 d. A weaker second signal may be present at P=177.84+-0.18 with \Delta V = 0.007+-0.002, likely corresponding to fundamental mode pulsation if the primary signal represents overtone pulsation (123.04/177.84 = 0.69). The star, with a spectroscopic reddening of E(B-V) = 1.02, is associated with heavily-reddened B-type stars in its immediate vicinity that appear to be outlying members of an anonymous young cluster centered ~10 arcmin to the west and 1661+-73 pc distant. The cluster has nuclear and coronal radii of r_n=3.5 arcmin and R_c=14 arcmin, respectively, while the parameters for HD 18391 derived from membership in the cluster with its outlying B stars are consistent with those implied by its Cepheid-like pulsation, provided that it follows the semi-period-luminosity relation expected of such objects. Its inferred luminosity as a cluster member is M_V=-7.76+-0.10, its age (9+-1)x10^6 years, and its evolutionary mass ~19 M_{\sun}. HD 18391 is not a classical Cepheid, yet it follows the Cepheid period-luminosity relation closely, much like another Cepheid impostor, V810 Cen.
We use mock images of $z=0.1$ galaxies in the 100 Mpc EAGLE simulation to establish the differences between the sizes and morphologies inferred from the stellar mass distributions and the optical light distributions. The optical, $r$-band images used were constructed with a radiative transfer method to account for the effects of dust, and we measure galaxy structural parameters by fitting S\'ersic models to the images with Galfit. We find that the derived $r$-band half-light radii differ systematically from the stellar half-mass radii, as the $r$-band sizes are typically 0.1 dex larger, and can deviate by as much as $\approx0.5$ dex. The magnitude of this size discrepancy depends strongly on the dust attenuation and star formation activity within the galaxy, as well as the measurement method used. Consequently, we demonstrate that the $r$-band sizes significantly improve the agreement between the simulated and observed stellar mass-size relation: star-forming and quiescent galaxies in EAGLE are typically only slightly larger than observed in the GAMA survey (by 0.1 dex), and the slope and scatter of the local mass-size relation are reproduced well for both populations. Finally, we also compare the obtained morphologies with measurements from GAMA, finding that too few EAGLE galaxies have light profiles that are similar to local early-type galaxies (S\'ersic indices of $n\sim 4$). Despite the presence of a significant population of triaxial systems among the simulated galaxies, the surface brightness and stellar mass density profiles tend to be closer to exponential discs ($n\sim1-2$). Our results highlight the need to measure the sizes and morphologies of simulated galaxies using common observational methods in order to perform a meaningful comparison with observations.
We apply an efficient selection method to identify potential weak Very Long Baseline Interferometry (VLBI) target quasars simply using optical (SDSS) and low-resolution radio (FIRST) catalogue data. Our search is restricted to within 12" from known compact radio sources that are detectable as phase-reference calibrators for ASTRO-G at 8.4 GHz frequency. These calibrators have estimated correlated flux density >20 mJy on the longest ground-space VLBI baselines. The search radius corresponds to the primary beam size of the ASTRO-G antenna. We show that ~20 quasars with at least mJy-level expected flux density can be pre-selected as potential in-beam phase-reference targets for ASTRO-G at 8.4 GHz frequency. Most of them have never been imaged with VLBI. The sample of these dominantly weak sources offers a good opportunity to study their radio structures with unprecedented angular resolution provided by Space VLBI. The method of in-beam phase-referencing is independent from the ability of the orbiting radio telescope to do rapid position-switching manoeuvres between the calibrators and the nearby reference sources, and less sensitive to the satellite orbit determination uncertainties.
We perform a comprehensive determination of the systemic proper motions of 74 dwarf galaxies and dwarf galaxy candidates in the Local Group based on Gaia early data release 3. The outputs of the analysis for each galaxy, including probabilities of membership, will be made publicly available. The analysis is augmented by a determination of the orbital properties of galaxies within 500 kpc. We adopt the flexible Bayesian methodology presented by McConnachie \& Venn (2020), which takes into account the location of the stars on the sky, on the colour-magnitude diagram and on the proper motion plane. We apply some modifications, in particular to the way the colour-magnitude diagram and spectroscopic information are factored in, e.g. by including stars in several evolution phases. The bulk motions are integrated in three gravitational potentials: two where the Milky Way is treated in isolation and has a mass 0.9 \& 1.6 $\times 10^{12}$M$_{\odot}$ and the time-varying potential by Vasiliev et al. (2021), which includes the infall of a massive Large Magellanic Cloud (LMC). We are able to determine bulk proper motions for 73 systems, and we consider reliable 66 of these measurements. For the first time, systemic motions are presented for galaxies out to a distance of 1.4 Mpc, in the NGC~3109 association. The inclusion of the infall of a massive LMC significantly modifies the orbital trajectories of the objects, with respect to orbit integration in static Milky Way-only potentials, and leads to 6 galaxies being likely associated to the LMC, 3 possibly associated and 1 recently captured object. We discuss the results of the orbit integration in the context of the relation of the galaxies to the system of Milky Way satellites, implications for the too-big-to-fail problem, impact on star formation histories, and tidal disruption.
A K-theoretic analogue of RSK insertion and Knuth equivalence relations was first introduced in 2006 by Buch, Kresch, Shimozono, Tamvakis, and Yong. The resulting K-Knuth equivalence relations on words and increasing tableaux on [n] has prompted investigation into the equivalence classes of tableaux arising from these relations. Of particular interest are the tableaux that are unique in their class, which we refer to as unique rectification targets (URTs). In this paper we give several new families of URTs and a bound on the length of intermediate words connecting two K-Knuth equivalent words. In addition, we describe an algorithm to determine if two words are K-Knuth equivalent and to compute all K-Knuth equivalence classes of tableaux on [n].
Different models of the role of creation of superheavy particles in the early Friedmann Universe with their subsequent decay on light particles are investigated. The observable numbers of baryon and entropy are predicted. The possible role of superheavy particles in creation of cold dark matter is discussed.
We report on some extensive computations and experiments concerning the moments of quadratic Dirichlet $L$-functions at the critical point. We computed the values of $L(1/2,\chi_d)$ for $- 5\times 10^{10} < d < 1.3 \times 10^{10}$ in order to numerically test conjectures concerning the moments $\sum_{|d|<X} L(1/2,\chi_d)^k$. Specifically, we tested the full asymptotics for the moments conjectured by Conrey, Farmer, Keating, Rubinstein, and Snaith, as well as the conjectures of Diaconu, Goldfeld, Hoffstein, and Zhang concerning additional lower terms in the moments. We also describe the algorithms used for this large scale computation.
We translate O'Meara's classification Theorem 93:28 in terms of BONGs. BONGs, short for "basis of norm generators", are a new way of describing quadratic lattices, an alternative to the traditional Jordan decompositions. They were introduced in [B].   Our result has its own merits as it is somewhat simpler than O'Meara's 93:28. However, it's main importance is that it is a prerequisite for a future work where we solve the more complicated problem of representation.   [B] C. N. Beli, Integral spinor norms over dyadic local fields, J. Number Theory 102 (2003) 125-182.
Video action anticipation aims to predict future action categories from observed frames. Current state-of-the-art approaches mainly resort to recurrent neural networks to encode history information into hidden states, and predict future actions from the hidden representations. It is well known that the recurrent pipeline is inefficient in capturing long-term information which may limit its performance in predication task. To address this problem, this paper proposes a simple yet efficient Temporal Transformer with Progressive Prediction (TTPP) framework, which repurposes a Transformer-style architecture to aggregate observed features, and then leverages a light-weight network to progressively predict future features and actions. Specifically, predicted features along with predicted probabilities are accumulated into the inputs of subsequent prediction. We evaluate our approach on three action datasets, namely TVSeries, THUMOS-14, and TV-Human-Interaction. Additionally we also conduct a comprehensive study for several popular aggregation and prediction strategies. Extensive results show that TTPP not only outperforms the state-of-the-art methods but also more efficient.
We evaluate the gauge invariant effective potential for the composite field $\sigma=2\Phi^{\dagger}\Phi$ in the SU(2)-Higgs model at finite temperature. Symmetric and broken phases correspond to the domains $\sigma\leq T^2/3$ and $\sigma > T^2/3$, respectively. The effective potential increases very steeply at small values of $\sigma$. Predictions for several observables, derived from the ordinary and the gauge invariant effective potential, are compared. Good agreement is found for the critical temperature and the jump in the order parameter. The results for the latent heat differ significantly for large Higgs masses.
The Magellanic Clouds host a large population of massive (> 10^4 Msun) star clusters with ages ranging from a few Myr to 12 Gyr. In nearly all cases, close inspection of their CMDs reveals features that deviate from expectations of a classic isochrone. Young (< 2 Gyr) clusters show extended main sequence turnoffs and in some cases split/dual main sequences. Clusters older than ~ 2 Gyr show splitting in the red giant branches when viewed in UV filters that are sensitive to abundance variations (in particular nitrogen). A distribution of stellar rotation rates appears to be the cause of the complex features observed in the young and intermediate age clusters, while above ~ 2 Gyr the features seem to be the same light-element abundance variations as observed in the ancient Galactic globular clusters, a.k.a. "multiple populations". Here, we provide an overview of current observations and their interpretations and summarise possible links between all the classes of complexities, regardless of age.
Molecular oxygen, O$_2$, was recently detected in comet 67P by the ROSINA instrument on board the Rosetta spacecraft with a surprisingly high abundance of 4 % relative to H$_2$O, making O$_2$ the fourth most abundant in comet 67P. Other volatile species with similar volatility, such as molecular nitrogen N$_2$, were also detected by Rosetta, but with much lower abundances and much weaker correlations with water. Here, we investigate the chemical and physical origin of O$_2$ and other volatile species using the new constraints provided by Rosetta. We follow the chemical evolution during star formation with state-of-the-art astrochemical models applied to dynamical physical models by considering three origins: i) in dark clouds, ii) during forming protostellar disks, and iii) during luminosity outbursts in disks. The models presented here favour a dark cloud (or "primordial") grain surface chemistry origin for volatile species in comets, albeit for dark clouds which are slightly warmer and denser than those usually considered as solar system progenitors.
We call attention to the surprising similarity between the newly discovered planetary system around PSR B1257+12 and the inner solar system. The similarity is in the ratios of the orbital radii and the masses of the three planets.
We study the effects of $N^{*}(1440)$ resonance on the production of kaons, antikaons and antiprotons in heavy-ion collisions at subthreshold energies. Using free-space widths for the $\Delta(1232)$ and the $N^{*}(1440)$ resonance and free-space thresholds for particle production, it is found that the $N^{*}$-baryon interactions contribute about 10\%, 25\% and 80\% to the yield of kaon, antikaon and antiproton, respectively. Doubling the widths of resonances due to possible medium effects, both the total and the $N^{*}$ induced antiproton yield decrease by about a factor of 3. Using a reduced antiproton production threshold in a nuclear medium as a result of dropping in-medium nucleon and antiproton masses, the total and the $N^{*}$ induced antiproton yield increase by a factor of 35 and 27, respectively, and the contribution of the $N^{*}$ induced collisions is reduced to about 50\% of the total.
The reaction $\gamma + p\to \eta^\prime + p$ is investigated in the quark model approach. The quark model predicts that the off-shell contributions from the resonance $S_{11}(1535)$ dominate the $\etap$ production in the threshold region. We find that the coulping constant $\alpha_{\etap NN}$ from the fit to a few total cross section data is small. The results of the total and differential cross sections are presented at different energies, which can be tested in the future experiments. If the future total cross data indeed show a resonance structure around 2 GeV suggested in a recent study, it would be an evidence of a non $qqq$ structure in its wavefunction.
Observations of Markarian 231 at 1.1 microns taken with NICMOS on the Hubble Space Telescope are described. The brightness of the object in the near infrared and the inherent short-term stability of the NICMOS optical and instrumental system enables application of special observational and analysis techniques that effectively increase high spatial resolution. By these means, we set an upper limit on the size of the core of the AGN nucleus at 8 mas corresponding to a radial projected distance from the center of MArkarian 231 of ~ 3pc.
Extended emission is a mystery in short gamma-ray bursts (SGRBs). By making time resolved spectral analyses of brightest nine events observed by ${\it Swift}$ XRT, we obviously classify the early X-ray emission of SGRBs into two types. One is the extended emission with exponentially rapid decay, which shows significant spectral softening during hundreds seconds since the SGRB trigger and is also detected by ${\it Swift}$-BAT. The other is a dim afterglow only showing power-law decay over $10^4$ s. The correlations between the temporal decay and spectral indices of the extended emissions are inconsistent with the $\alpha$-$\beta$ correlation expected for the high-latitude curvature emission from a uniform jet. The observed too-rapid decay suggests the emission from a photosphere or a patchy surface, and manifests the stopping central engine via such as magnetic reconnection at the black hole.
We study tunneling of the magnetic moment in a particle that has full rotational freedom. Exact energy levels are obtained and the ground-state magnetic moment is computed for a symmetric rotor. The effect of the mechanical freedom on spin tunneling manifests itself in a strong dependence of the magnetic moment on the moments of inertia of the rotor. Energy of the particle exhibits quantum phase transitions between states with different values of the magnetic moment. Particles of various shapes are investigated and quantum phase diagram is obtained.