ShantanuT01/DACTYL-Pretraining huggingface dataset:
In this paper we present the results of a high temperature (300 K<T<800 K) neutron powder diffraction study of the La1.4Sr1.6Mn2O7 bilayered manganite. An unusual trend of the <Mn-Oapical>/Mn-Oequatorial parameter was found: it first decreases up to 500 K and then increases up to the highest T measured. At the same time, a significant shortening of the apical Mn-O(2) bond is observed in the range where the J-T distortion is reduced. The overall data gained by this study may suggest a shift of electronic density from axial to planar eg orbitals with T. This trend is explained considering of the presence of short range magnetic interaction well above TC.
Deep neural networks (DNNs) are known to be vulnerable to adversarial examples. Existing works have mostly focused on either digital adversarial examples created via small and imperceptible perturbations, or physical-world adversarial examples created with large and less realistic distortions that are easily identified by human observers. In this paper, we propose a novel approach, called Adversarial Camouflage (\emph{AdvCam}), to craft and camouflage physical-world adversarial examples into natural styles that appear legitimate to human observers. Specifically, \emph{AdvCam} transfers large adversarial perturbations into customized styles, which are then "hidden" on-target object or off-target background. Experimental evaluation shows that, in both digital and physical-world scenarios, adversarial examples crafted by \emph{AdvCam} are well camouflaged and highly stealthy, while remaining effective in fooling state-of-the-art DNN image classifiers. Hence, \emph{AdvCam} is a flexible approach that can help craft stealthy attacks to evaluate the robustness of DNNs. \emph{AdvCam} can also be used to protect private information from being detected by deep learning systems.
Misner spacetime is among the simplest solutions of Einstein's equation that exhibits a Cauchy horizon with a smooth extension beyond it. Besides violating strong cosmic censorship, this extension contains closed timelike curves. We analyze the stability of the Cauchy horizon, and prove that neighboring spacetimes in one parameter families of solutions through Misner's in pure gravity, gravity coupled to a scalar field, or Einstein-Maxwell theory, end at the Cauchy horizon developing a curvature singularity.
We apply our Yennie-Frautschi-Suura exponentiated cross section formulas for the parton processes $q + {^(} \bar q {^)}{^\prime} \ra q{^\prime}{^\prime} + {^(} \bar q {^)}{^\prime}{^\prime}{^\prime} + n(G)$ to the process $q + \bar q \ra t + \bar t + n(G)$ at FNAL energies, where G is a QCD gluon. We use semi-analytical methods to compute the ratio $r_{exp}=\sigma_{exp}/\sigma_B$, where $\sigma_{exp}$ is our soft gluon YFS exponentiated cross section and $\sigma_B$ is the Born cross section. For $m_t= 0.176(0.199)$TeV, we get $r_{exp}=1.65(1.48)$, respectively, for $q=u$ for example. These results are not inconsistent with the recent observations by CDF and D0.
We construct the general four-dimensional N=2 supergravity theory coupled to vector and vector-tensor multiplets only. Consistency of the construction requires the introduction of the vector fields dual to those sitting in the same supermultiplets as the antisymmetric tensors, as well as the scalar fields dual to the tensors themselves. Gauge symmetries also involving these additional fields guarantee the correct counting of the physical degrees of freedom.
The paper suggests a way of stochastic integration of random integrands with respect to fractional Brownian motion with the Hurst parameter H> 1/2. The integral is defined initially on the processes that are "piecewise" predictable on a short horizon. Then the integral is extended on a wide class of square integrable adapted random processes. This class is described via a mild restriction on the growth rate of the conditional mean square error for the forecast on an arbitrarily short horizon given current observations; differentiability of H\"older property of any kind or degree is not required for the integrand. The suggested integration can be interpreted as foresighted integration for integrands featuring corresponding restrictions on the forecasting error. This integration is based on It\^o's integration and does not involve Malliavin calculus or Wick products. In addition, it is shown that these stochastic integrals depend continuously on H at H=1/2+0.
A theory is presented showing that, under appropriate conditions, a ferroelectric in a cavity resonator can emit superradiant pulses. Initially, the ferroelectric has to be prepared in a nonequilibrium state from which it relaxes emitting a coherent pulse in the infrared region. Polarization dipolar waves play the role of the triggering mechanism initiating the beginning of the process.
By performing a derivative expansion on a class of boosted Born-Infeld-AdS_5 black branes, we study the hydrodynamics of the dual field theory - in the spirit of AdS/CFT correspondence. We determine the fluid dynamical stress-energy tensor to first order, and find that the ratio of the shear viscosity to entropy density conforms to the universal value of $1/4\pi$ to all orders of the inverse of the Born-Infeld parameter.
We study the baby Skyrme model in a pure AdS background without a mass term. The tail decays and scalings of massless radial solutions are demonstrated to take a similar form to those of the massive flat space model, with the AdS curvature playing a similar role to the flat space pion mass. We also numerically find minimal energy solutions for a range of higher topological charges and find that they form concentric ring-like solutions. Popcorn transitions (named in analogy with studies of toy models of holographic QCD) from an n layer to an n+1-layer configuration are observed at topological charges 9 and 27 and further popcorn transitions for higher charges are predicted. Finally, a point-particle approximation for the model is derived and used to successfully predict the ring structures and popcorn transitions for higher charge solitons.
Let $X$ and $Y$ denote two independent squared Bessel processes of dimension $m$ and $n-m$, respectively, with $n\geq 2$ and $m \in [0, n)$, making $X+Y$ a squared Bessel process of dimension $n$. For appropriately chosen function $s$, the process $s (X+Y)$ is a local martingale. We study the representation and the dynamics of $s(X+Y)$, projected on the filtration generated by $X$. This projection is a strict supermartingale if, and only if, $m<2$. The finite-variation term in its Doob-Meyer decomposition only charges the support of the Markov local time of $X$ at zero.
Using binary evolution with Case-C mass transfer, the spins of several black holes (BHs) in X$-$ray binaries (XBs) have been predicted and confirmed (three cases) by observations. The rotational energy of these BHs is sufficient to power up long gamma$-$ray bursts and hypernovae (GRBs/HNe) and still leave a Kerr BH behind. However, strong magnetic fields and/or dynamo effects in the interior of such stars deplete their cores from angular momentum preventing the formation of collapsars. Thus, even though binaries can produce Kerr BHs, most of their rotation is acquired from the stellar mantle, with a long delay between BH formation and spin up. Such binaries would not form GRBs. We study whether the conditions required to produce GRBs can be met by the progenitors of such BHs. Tidal-synchronization and Alfv\'en timescales are compared for magnetic fields of different intensities threading He stars. A search is made for a magnetic field range which allows tidal spin up all the way in to the stellar core but prevents its slow down during differential rotation phases. The energetics for producing a strong magnetic field during core collapse, which may allow for a GRB central engine, are also estimated. An observationally-reasonable choice of parameters is found ($B \lesssim10^2$ G threading a slowly-rotating He star) which allows Fe cores to retain substantial angular momentum. Thus, the Case-C-mass-transfer binary channel is capable of explaining long GRBs. However, the progenitors must have low initial spin and low internal magnetic field throughout their H-burning and He-burning phases.
A key goal of many Cosmic Microwave Background experiments is the detection of gravitational waves, through their B-mode polarization signal at large scales. To extract such a signal requires modelling contamination from the Galaxy. Using the Planck experiment as an example, we investigate the impact of incorrectly modelling foregrounds on estimates of the polarized CMB, quantified by the bias in tensor-to-scalar ratio r, and optical depth tau. We use a Bayesian parameter estimation method to estimate the CMB, synchrotron, and thermal dust components from simulated observations spanning 30-353 GHz, starting from a model that fits the simulated data, returning r<0.03 at 95% confidence for an r=0 model, and r=0.09+-0.03 for an r=0.1 model. We then introduce a set of mismatches between the simulated data and assumed model. Including a curvature of the synchrotron spectral index with frequency, but assuming a power-law model, can bias r high by ~1-sigma (delta r ~ 0.03). A similar bias is seen for thermal dust with a modified black-body frequency dependence, incorrectly modelled as a power-law. If too much freedom is allowed in the model, for example fitting for spectral indices in 3 degree pixels over the sky with physically reasonable priors, we find r can be biased up to ~3-sigma high by effectively setting the indices to the wrong values. Increasing the signal-to-noise ratio by reducing parameters, or adding additional foreground data, reduces the bias. We also find that neglecting a 1% polarized free-free or spinning dust component has a negligible effect on r. These tests highlight the importance of modelling the foregrounds in a way that allows for sufficient complexity, while minimizing the number of free parameters.
We prove that there are no Wieferich's primes $q=2p+1$ where $p \equiv 3 \pmod{4}$ is a prime number
We study the multiple scattering Sunyaev-Zeldovich (SZ) signature, extending our previous analysis to high-temperature clusters. We consistently treat the anisotropy of the ambient radiation field caused by the first scattering and also consider lowest order kinematic terms. We show that due to temperature corrections monopole through octupole anisotropy of the singly scattered SZ signal attain different spectra in the second scattering. The difference becomes more pronounced at high temperature, and thus could be used to constrain individual line of sight moments of the electron density and temperature profiles. While very challenging from the observational point of view, this further extends the list of possible SZ observables that will be important for 3D cluster-profile reconstruction, possibly helping to break geometric degeneracies caused by projection effects. We also briefly discuss the scattering of primordial CMB anisotropies by SZ clusters.
Using the generalized normally ordered form of words in a locally-free group of $n$ generators, we show that in the limit $n\to\infty$, the partition function of weighted directed lattice animals on a semi-infinite strip coincides with the partition function of stationary configurations of the asymmetric simple exclusion process (ASEP) with arbitrary entry/escape rates through open boundaries. We relate the features of the ASEP in the different regimes of the phase diagram to the geometric features of the associated generalized directed animals by showing the results of numerical simulations. In particular, we show how the presence of shocks at the first order transition line translates into the directed animal picture. Using the evolution equation for generalized, weighted Lukasiewicz paths, we also provide a straightforward calculation of the known ASEP generating function.
This paper is a written version of a one hour lecture given on Peter Shor's quantum factoring algorithm.
While stars are widely discussed as the source of the high energy photons which reionized the universe, an additional source of ionizing photons that must also contribute to reionization in this scenario is the supernovae (SNe) which mark the end of the life of massive stars. Here we estimate the relative contributions of SNe and stars to reionization. While the rate at which ionizing photons are produced in SN shocks is well below that at which they are produced by stars, the harder spectra of radiation emitted from SNe leads to an enhanced escape fraction of SN generated photons relative to that of stellar photons. In particular, along a given line of sight out of a galaxy, we find that for neutral hydrogen column densities N_H >~10^18 cm^-2 the contribution to reionization from SNe is greater than that from stars. Drawing on the results of simulations presented in the literature, we find that the overall (line of sight-averaged) SNe shock-generated ionizing photon escape fraction is larger than the stellar photon escape fraction by a factor of \simeq 4 to \simeq 7, depending on the metallicity of the stellar population. Overall, our results suggest that the effect of SNe is an enhancement of up to ~ 10 percent in the fraction of hydrogen reionized by stellar sources. We briefly discuss the implications of our results for the population of galaxies responsible for reionization.
A recent paper from Raveau's group (arXiv:1106.6253) has shown the existence of a glass-like arrested state in two calcium-doped cobaltites, which consists of coexisting ferromagnetic and antiferromagnetic phase fractions, resulting from arrest of kinetics at low temperature,. They use the "cooling and heating in unequal magnetic field (CHUF)" measurement protocol to show devitrification of the arrested state. They use the same section title, protocol name, and acronym as in the paper (arXiv:0805.1514) where the protocol was presented, justified, and exploited. They nowhere refer to that paper, or to its journal counterpart. We put the development of this CHUF protocol in perspective, bringing out that it was conceived for broadened first order transitions where the kinetics of the transformation gets hindered. We also point out its applicability in view of our various subsequent works (arXiv:0911.4552, arXiv:1003.4400 and their journal counterparts) further exploiting this protocol. The paper being commented on is also silent about these latter papers (or their journal counterparts) even though the use of this protocol is highlighted in these in the abstract itself.
The model under consideration is a two-dimensional two-component plasma, stable against collapse for the dimensionless coupling constant $\beta<2$. The combination of a technique of renormalized Mayer expansion with the mapping onto the sine-Gordon theory provides the full thermodynamics of the plasma in the whole stability range of $\beta$. The explicit forms of the density-fugacity relationship and of the specific heat (at constant volume) per particle are presented.
We introduce an approach for pre-training egocentric video models using large-scale third-person video datasets. Learning from purely egocentric data is limited by low dataset scale and diversity, while using purely exocentric (third-person) data introduces a large domain mismatch. Our idea is to discover latent signals in third-person video that are predictive of key egocentric-specific properties. Incorporating these signals as knowledge distillation losses during pre-training results in models that benefit from both the scale and diversity of third-person video data, as well as representations that capture salient egocentric properties. Our experiments show that our Ego-Exo framework can be seamlessly integrated into standard video models; it outperforms all baselines when fine-tuned for egocentric activity recognition, achieving state-of-the-art results on Charades-Ego and EPIC-Kitchens-100.
The periodic Anderson lattice model for the crystalline electric field (CEF)split 4f quartet states is used to describe the Yb-based Kondo insulators/semiconductors. In the slave-boson mean-field approximation, we derive the hybridized quasiparticle bands, and find that decreasing the hybridization difference of the two CEF quartets may induce an insulator-to-metal phase transition. The resulting metallic phase has a hole and an electron Fermi pockets. Such a phase transition may be realized experimentally by applying pressure, reducing the difference in hybridization of the two CEF quartets.
A new method is presented for performing first-principles molecular-dynamics simulations of systems with variable occupancies. We adopt a matrix representation for the one-particle statistical operator Gamma, to introduce a ``projected'' free energy functional G that depends on the Kohn-Sham orbitals only and that is invariant under their unitary transformations. The Liouville equation [ Gamma , H ] = 0 is always satisfied, guaranteeing a very efficient and stable variational minimization algorithm that can be extended to non-conventional entropic formulations or fictitious thermal distributions.
The particle spectra and Hanbury-Brown Twiss (HBT) radius of Au+Au collisions at RHIC energy are investigated by a hydrodynamical expanding source with both shear and bulk viscosities ($\zeta$). With a large width of the ratio of $\zeta$ to entropy density $s$, both the particle transverse momentum spectra and the ratio $R_{out}/R_{side}$ of HBT radii in the direction of the total transverse momentum of detected two particles ($R_{out}$) and perpendicular to both this direction and the beam direction ($R_{side}$) become a little steeper.
During the last 15 years, a standard paradigm has emerged to explain both the progenitor nature and the observed radiations of gamma-ray bursts. In this work we show three GRBs for which the standard paradigm could be tested with high statistics due to their exceptional spectral and temporal coverage. While GRB 1110205 represents a very good example of the standard scenario, GRB 090102 and GRB 111209A do not fit into the standard paradigm.
In this article we present the post-Newtonian (pN) coefficients of the energy flux (and angular momentum flux) at infinity and event horizon for a particle in circular, equatorial orbits about a Kerr black hole (of mass $M$ and spin-parameter $a$) up to 20-pN order. When a pN term is not a polynomial in $a/M$ and includes irrational functions (like polygamma functions), it is written as a power series of $a/M$. This is achieved by calculating the fluxes numerically with an accuracy greater than 1 part in $10^{600}$. Such high accuracy allows us to extract analytical values of pN coefficients that are linear combinations of transcendentals like the Euler constant, logarithms of prime numbers and powers of $\pi$. We also present the 22-pN expansion (spin-independent pN expansion) of the ingoing energy flux at the event horizon for a particle in circular orbit about a Schwarzschild black hole.
We give again the proof of several classical results concerning the cyclotomic approach to Fermat's last theorem using exclusively class field theory (essentially the reflection theorems), without any calculations. The fact that this is possible suggests a part of the logical inefficiency of the historical investigations. We analyze the significance of the numerous computations of the literature, to show how they are probably too local to get any proof of the theorem. However we use the derivation method of Eichler as a prerequisite for our purpose, a method which is also local but more effective. Then we propose some modest ways of study in a more diophantine context using radicals; this point of view would require further nonalgebraic investigations.
An expression for the spin-orbit interaction coupling between different levels, which was shown to be aberrant more than thirty years ago persists in the literature without clear indication of what is used. It leads to expressions quite simpler than they should be. After an attempt to warn the community of the nuclear physicists on this strange situation (nucl-th/0312038), the authors of the publication in which the "aberrant" interaction is described and used, try to justify their work (nucl-th/0401055), by a very strange "symmetrization" of something already symmetric. They claim also that their method allows to solve some problem related to the Pauli principle and give some references, among which a book which reports the solution of such problem almost forty years ago, with a very small effect. An examination of their own results shows that their optimism is not completely justified. Nevertheless, any user of ECIS, sensitive to their arguments, is requested to ask their opinion to these five coauthors before publishing.
We present a method to correct for deflections of ultra-high energy cosmic rays in the galactic magnetic field. We perform these corrections by simulating the expected arrival directions of protons using a parameterization of the field derived from Faraday rotation and synchrotron emission measurements. To evaluate the method we introduce a simulated astrophysical scenario and two observables designed for testing cosmic ray deflections. We show that protons can be identified by taking advantage of the galactic magnetic field pattern. Consequently, cosmic ray deflection in the galactic field can be verified experimentally. The method also enables searches for directional correlations of cosmic rays with source candidates.
An explicit parameterization is given for the density matrices for $n$-state systems. The geometry of the space of pure and mixed states and the entropy of the $n$-state system is discussed. Geometric phases can arise in only specific subspaces of the space of all density matrices. The possibility of obtaining nontrivial abelian and nonabelian geometric phases in these subspaces is discussed.
We show the Jordan property for regional fundamental groups of klt singularities of fixed dimension. Furthermore, we prove the existence of effective simultaneous index one covers for $n$-dimensional klt singularities. We give an application to the study of local class groups of klt singularities.
Self-consistent solutions of Hedin's diagrammatic theory equations (HE) for the two-site Hubbard Model (HM) have been studied. They have been found for three-point vertices of increasing complexity ($\Gamma=1$ (GW approximation), $\Gamma_{1}$ from the first order perturbation theory, and exact vertex $\Gamma_{E}$). The comparison is being made when an additional quasiparticle (QP) approximation for the Green function is applied during the self-consistent iterative solving of HE and when QP approximation is not applied. The results obtained with the exact vertex are directly related to the presently open question - which approximation is more advantageous for future implementations - GW+DMFT or QPGW+DMFT. It is shown that in the regime of strong correlations only originally proposed GW+DMFT scheme is able to provide reliable results. Vertex corrections based on Perturbation Theory (PT) systematically improve the GW results when full self-consistency is applied. The application of the QP self-consistency combined with PT vertex corrections shows similar problems to the case when the exact vertex is applied combined with QP sc. The analysis of Ward Identity violation is performed for all studied in this work approximations and its relation to the general accuracy of the schemes used is provided.
A set of localized, non-Abelian anyons - such as vortices in a p_x + i p_y superconductor or quasiholes in certain quantum Hall states - gives rise to a macroscopic degeneracy. Such a degeneracy is split in the presence of interactions between the anyons. Here we show that in two spatial dimensions this splitting selects a unique collective state as ground state of the interacting many-body system. This collective state can be a novel gapped quantum liquid nucleated inside the original parent liquid (of which the anyons are excitations). This physics is of relevance for any quantum Hall plateau realizing a non-Abelian quantum Hall state when moving off the center of the plateau.