ShantanuT01/DACTYL-Pretraining huggingface dataset:
This paper presents a novel approach in a rarely studied area of computer vision: Human interaction recognition in still images. We explore whether the facial regions and their spatial configurations contribute to the recognition of interactions. In this respect, our method involves extraction of several visual features from the facial regions, as well as incorporation of scene characteristics and deep features to the recognition. Extracted multiple features are utilized within a discriminative learning framework for recognizing interactions between people. Our designed facial descriptors are based on the observation that relative positions, size and locations of the faces are likely to be important for characterizing human interactions. Since there is no available dataset in this relatively new domain, a comprehensive new dataset which includes several images of human interactions is collected. Our experimental results show that faces and scene characteristics contain important information to recognize interactions between people.
We study a gravity solution corresponding to fivebranes wrapped on the $S^2$ of the resolved conifold. By changing a parameter the solution continuously interpolates between the deformed conifold with flux and the resolved conifold with branes. Therefore, it displays a geometric transition, purely in the supergravity context. The solution is a simple example of torsional geometry and may be thought of as a non-K\"ahler analog of the conifold. By U-duality transformations we can add D3 brane charge and recover the solution in the form originally derived by Butti et al. This describes the baryonic branch of the Klebanov-Strassler theory. Far along the baryonic branch the field theory gives rise to a fuzzy two-sphere. This corresponds to the D5 branes wrapping the two-sphere of the resolved conifold in the gravity solution.
The Large Area Proportional Counter (LAXPC) instruments onboard the AstroSat Observatory has observed the X-ray binary system Her X-1 during AstroSat observing sessions AO2, AO3 and TO2. These include observations while Her X-1 is in different stages of its 35 day cycle: Low State, Turn-on to Main High State, peak of Main High State and early decline of Main High State. These observations also include a number of dips and one egress of neutron star eclipse. Here we present light curves and softness ratio analysis for these observations and discuss new features of the spectral changes with 35-day phase and orbital phase. We find a new phenomenon for dips during Main High state: About half of the dips show constant softness ratio as count rate decreases, which has not been seen before, and could be caused by highly ionized matter or very dense cold matter. The other half of the dips show the normal decrease of softness ratio as count rate decreases. These are caused by cold matter absorption and were previously known.
We present correlations involving central intensity ratio (CIR) of 52 early type galaxies, including 24 ellipticals and 28 lenticulars, selected from low density environment in the nearby (< 30 Mpc) universe. CIR is found to be negatively and significantly correlated with the mass of the central super massive black hole, central velocity dispersion, absolute B band magnitude, stellar bulge mass and central Mg2 index of the host galaxy. The study proposes the use of CIR as a simple, fast and efficient photometric tool for exploring the co-evolution scenario existing in galaxies.
An argument against tolerating finetuning in the Higgs sector is presented, by emphasizing the difference between (well understood) quantum corrections to scalar masses and the (unsolved) problem of the cosmological constant. I also point out that ``split'' supersymmetry, where all scalars except one Higgs boson have masses many orders of magnitude above the weak scale, is not compatible with simple mechanisms of transmitting supersymmetry breaking (gravity, gauge or anomaly mediation), unless a second, independent finetuning of parameters is introduced. This finetuning is required to obtain an acceptable ratio of vacuum expectation values tan(beta).
When testing multiple hypothesis in a survey --e.g. many different source locations, template waveforms, and so on-- the final result consists in a set of confidence intervals, each one at a desired confidence level. But the probability that at least one of these intervals does not cover the true value increases with the number of trials. With a sufficiently large array of confidence intervals, one can be sure that at least one is missing the true value. In particular, the probability of false claim of detection becomes not negligible. In order to compensate for this, one should increase the confidence level, at the price of a reduced detection power. False discovery rate control is a relatively new statistical procedure that bounds the number of mistakes made when performing multiple hypothesis tests. We shall review this method, discussing exercise applications to the field of gravitational wave surveys.
We construct loop soups for general Markov processes without transition densities and show that the associated permanental process is equal in distribution to the loop soup local time. This is used to establish isomorphism theorems connecting the local time of the original process with the associated permanental process. Further properties of the loop measure are studied.
We present the results of a multi-component synthetic spectral analysis of the archival far ultraviolet spectra of the hot components of several AM CVn double degenerate interacting binaries with known distances from trigonometric parallaxes. Our analysis was carried out using the code BINSYN (Linnell & Hubeny 1996) which takes into account the donor companion star, the shock front which forms at the disk edge and the FUV and NUV energy distribution. We fixed the distance of each system at its parallax-derived value and adopted appropriate values of orbital inclination and white dwarf mass. We find that the accretion-heated "DO/DB" WDs are contributing significantly to the FUV flux in four of the systems (ES Ceti, CR Boo, V803 Cen, HP Lib, GP Com). In two of the systems, GP Com and ES Ceti, the WD dominates the FUV/NUV flux. We present model-derived accretion rates which agree with the low end of the range of accretion rates derived earlier from black body fits over the entire spectral energy distribution. We find that the WD in ES Ceti is very likely not a direct impact accretor but has a small disk. The WD in ES Ceti has $T_{eff} \sim 40,000 \pm 10,000$K. This is far cooler than the previous estimate of Espaillat et al.(2005). We find that the WD in GP Com has $T_{eff} = 14,800 \pm500$K, which is hotter than the previously estimated temperature of 11,000K. We present a comparison between our empirical results and current theoretical predictions for these systems.
The low-frequency peaked BL Lac object (LBL) AP Librae exhibits very-high-energy (VHE, $E>100$GeV) $\gamma$-ray emission and hosts an extended jet, which has been detected in radio and X-rays. The jet X-ray spectral index implies an inverse Compton origin. These observations are unusual for LBLs calling for a consistent explanation of this extraordinary source. The observationally constrained parameters necessary to describe the core emission within the standard one-zone model are unable to explain the broad-band spectrum, even if observationally unconstrained external photon fields are taken into account. We demonstrate that the addition of the extended jet emission successfully reproduces the total spectral energy distribution. In particular, the VHE radiation is produced in the $>100\,$kpc long extended jet via inverse Compton scattering of cosmic microwave background photons by highly relativistic electrons. We present several ways to test this theory. The extended jet is weakly magnetized ($B_0 = 2.5\,\mu$G), while its minimum and maximum electron Lorentz factors are $\gamma_{min}=60$ and $\gamma_{max}=5\times 10^6$, respectively. The electron spectral index is $s=2.6$. These parameters are comparable to parameters of other blazars with extended X-ray jets dominated by inverse Compton scattering.
Given a food image, can a fine-grained object recognition engine tell "which restaurant which dish" the food belongs to? Such ultra-fine grained image recognition is the key for many applications like search by images, but it is very challenging because it needs to discern subtle difference between classes while dealing with the scarcity of training data. Fortunately, the ultra-fine granularity naturally brings rich relationships among object classes. This paper proposes a novel approach to exploit the rich relationships through bipartite-graph labels (BGL). We show how to model BGL in an overall convolutional neural networks and the resulting system can be optimized through back-propagation. We also show that it is computationally efficient in inference thanks to the bipartite structure. To facilitate the study, we construct a new food benchmark dataset, which consists of 37,885 food images collected from 6 restaurants and totally 975 menus. Experimental results on this new food and three other datasets demonstrates BGL advances previous works in fine-grained object recognition. An online demo is available at http://www.f-zhou.com/fg_demo/.
This Report summarizes the proceedings of the 2017 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) theoretical uncertainties and dataset dependence of parton distribution functions, (III) new developments in jet substructure techniques, (IV) issues in the theoretical description of the production of Standard Model Higgs bosons and how to relate experimental measurements, (V) phenomenological studies essential for comparing LHC data from Run II with theoretical predictions and projections for future measurements, and (VI) new developments in Monte Carlo event generators.
Let $G = (V_G,E_G)$ be a simple connected graph. The eccentric distance sum of $G$ is defined as $\xi^d(G)=\sum_{v \in V_G}\,\varepsilon_G(v)D_G(v),$ where $\varepsilon_G(v)$ is the eccentricity of the vertex $v$ and $D_G(v)=\sum_{u \in V_G}\,d(u,v)$ is the sum of all distances from the vertex $v$. In this paper, we characterize $n$-vertex unicyclic graphs with given matching number having the minimal and second minimal eccentric distance sums, respectively.
Distinctive power of the alliance polynomial has been studied in previous works, for instance, it has been proved that the empty, path, cycle, complete, complete without one edge and star graphs are characterized by its alliance polynomial. Moreover, it has been proved that the family of alliance polynomial of regular graphs with small degree is a very special one, since it does not contain alliance polynomial of graphs other than regular graph with the same degree. In this work we prove that the alliance polynomial also determines the wheel graphs.
.We expound an alternative to the Copenhagen interpretation of the formalism of nonrelativistic quantum mechanics. The basic difference is that the new interpretation is formulated in the language of epistemological realism. The {\psi} function is no longer interpreted as a probability amplitude of the observed behaviour of elementary particles but as an objective physical field representing the particles themselves. The particles are thus extended objects whose extension varies in time according to the variation of {\psi}. They are considered as fundamental regions of space with some kind of nonlocality. There is no wave-particle duality. The point-particle-like behaviour is explained by spatial contraction in a deterministic reduction process.
On an interval compactification in supersymmetric theory, boundary conditions for bulk fields must be treated carefully. If they are taken arbitrarily following the requirement that a theory is supersymmetric, the conditions could give redundant constraints on the theory. We construct a supersymmetric action integral on an interval by introducing brane interactions with which total derivative terms under the supersymmetry transformation become zero due to a cancellation. The variational principle leads equations of motion and also boundary conditions for bulk fields, which determine boundary values of bulk fields. By estimating mass spectrum, {\it spontaneous} supersymmetry breaking in this simple setup can be realized in a new framework. This supersymmetry breaking does not induce massless R-axion, which is favorable for phenomenology. It is worth noting that fermions in hyper-multiplet, gauge bosons, and the fifth-dimensional component of gauge bosons can have zero-modes (while the other components are all massive as Kaluza-Klein modes), which fits the gauge-Higgs unification scenarios.
According to the theory of functional inequalities, a non-symmetric Markov semigroup has better properties than the corresponding symmetric one. For instance, there exist non-symmetric Markov semigroups which are hypercontractive (and thus converge exponentially in both $L^2$ and entropy), but the symmetric ones are even not ergodic. In this paper, we aim to search for reasonable conditions to ensure that a non-symmetric Markov semigroup and its symmetrization share the properties of exponential convergence, uniform integrability, hypercontractivity, and supercontractivity. Since in the symmetric case these properties are precisely characterized by functional inequalities of the Dirichlet form, the key point of the study is to prove these inequalities for non-symmetric Markov processes. SDEs driven by Brownian motion or L\'evy jump process are investigated.
We have recently discovered five Lyman continuum leaking galaxies at z~0.3, selected for their compactness, intense star-formation, and high [OIII]/[OII] ratio (Izotov et al. 2016ab). Here we derive their ionizing photon production efficiency, a fundamental quantity for inferring the number of photons available to reionize the Universe, for the first time for galaxies with confirmed strong Lyman continuum escape (fesc~6-13%). We find an ionizing photon production per unit UV luminosity, which is a factor 2-6 times higher than the canonical value when reported to their observed UV luminosity. After correction for extinction this value is close to the canonical value. The properties of our five Lyman continuum leakers are found to be very similar to those of the confirmed z=3.218 leaker Ion2 from de Barros et al. (2016) and very similar to those of typical star-forming galaxies at z>~6. Our results suggest that UV bright galaxies at high-z such as Lyman break galaxies can be Lyman continuum leakers and that their contribution to cosmic reionization may be underestimated.
We prove that if a directed multigraph $D$ has at most $t$ pairwise arc-disjoint directed triangles, then there exists a set of less than $2t$ arcs in $D$ which meets all directed triangles in $D$, except in the trivial case $t=0$. This answers affirmatively a question of Tuza from 1990.
Let S be a sphere in R^n such that S\capQ^n\neq\emptyset and let Cl denote the closure operator in the Euclidean topology of R^n. If the center of S is in Q^n, then Cl(S\capQ^n) is S, as is easily proved. If the center of S is not in Q^n, then what is Cl(S\capQ^n)? This question, which was answered partially in the author's paper [Proc. Japan Acad. Ser. A Math. Sci. 80 (2004), no. 7, 146--149], is answered completely in this paper by representing Cl(S\capQ^n) in terms of the group of Q-automorphisms of the algebraic closure of Q(\gamma_1,...,\gamma_n) in C, where \gamma_1,...,\gamma_n denote the coordinates of the center of S.
Polyakov has suggested that two dimensional turbulence might be described by a minimal model of conformal field theory. However, there are many minimal models satisfying the same physical inputs as Polyakov's solution (p,q)=(2,21). Dynamical magnetic fields and passive scalars pose different physical requirements. For large magnetic Reynolds number other minimal models arise. The simplest one, (p,q)=(2,13) makes reasonable predictions that may be tested in the astrophysical context. In particular, the equipartition theorem between magnetic and kinetic energies does not hold: the magnetic one dominates at larger distances.
Synthesized by the wet chemical precipitation technique hydroxyapatite powders (HAp) with the sizes of the crystallites of (20-50) nm and 1000 nm were analyzed by different analytical methods. By means of electron paramagnetic resonance (EPR) it is shown that during the synthesis process nitrate anions from the reagents (by-products) could incorporate into the HAp structure. The concentration of the stable NO32- radicals detected after X-ray irradiation of the product at room temperature does not decrease even after annealing up to 400 oC. The relaxation times and EPR parameters of the axially symmetric NO32- paramagnetic centers are measured with high accuracy. Increased sensitivity and resolution of high-frequency EPR (95 GHz) allows to reveal additional paramagnetic centre(s) which origin is discussed. Analyses of electron-nuclear double resonance (ENDOR) spectra from 1H and 31P nuclei and ab-initio density functional theory (DFT) calculations allow suggesting that the paramagnetic centers and nitrate anions as the precursors of NO32- radicals preferably occupy PO43- site in the HAp structure.
We present the task of differential face morph attack detection using a conditional generative network (cGAN). To determine whether a face image in an identification document, such as a passport, is morphed or not, we propose an algorithm that learns to implicitly disentangle identities from the morphed image conditioned on the trusted reference image using the cGAN. Furthermore, the proposed method can also recover some underlying information about the second subject used in generating the morph. We performed experiments on AMSL face morph, MorGAN, and EMorGAN datasets to demonstrate the effectiveness of the proposed method. We also conducted cross-dataset and cross-attack detection experiments. We obtained promising results of 3% BPCER @ 10% APCER on intra-dataset evaluation, which is comparable to existing methods; and 4.6% BPCER @ 10% APCER on cross-dataset evaluation, which outperforms state-of-the-art methods by at least 13.9%.
We introduce a new class of permutations, called web permutations. Using these permutations, we provide a combinatorial interpretation for entries of the transition matrix between the Specht and web bases, which answers Rhoades's question. Furthermore, we study enumerative properties of these permutations.
We present the afterglow light curves produced by the deceleration of the non-relativistic ejecta mass in a stratified circumstellar medium with a density profile $n(r)\propto r^{-k}$ with $k=0$, $1$, $1.5$, $2$ and $2.5$. Once the ejecta mass is launched with equivalent kinetic energy parametrized by $E(>\beta)\propto \beta^{-\alpha}$ (where beta is the ejecta velocity) and propagates into the surrounding circumstellar medium, it first moves with constant velocity (the free-coasting phase), and later it decelerates (the Sedov-Taylor expansion). We present the predicted synchrotron and synchrotron-self Compton light curves during the free-coasting phase, and the subsequent Sedov-Taylor expansion. In particular cases, we show the corresponding light curves generated by the deceleration of several ejecta masses with different velocities launched during the coalescence of binary compact objects and the core-collapse of dying massive stars which will contribute at distinct timescales, frequencies, and intensities. Finally, using the multi-wavelength observations and upper limits collected by a large campaign of orbiting satellites and ground telescopes, we constrain the parameter space of both the KN afterglow in GW170817 and the possibly generated KN afterglow in S190814bv. Further observations on timescales of years post-merger are needed to derive tighter constraints.
The isostructural series of $S=1$ quantum magnets Cs$_{1-x}$Rb$_{x}$FeCl$_{3}$ is investigated, using both thermodynamic measurements and inelastic neutron scattering experiments. It is found that increasing Rb content the system evolves from the gapped state at $x=0$, through a quantum phase transition at $x\sim 0.35$, and to the magnetically ordered state at larger $x$. Inelastic neutron experiments for $x=0$, $x=0.3$, and $x=1$ demonstrate that the magnetic anisotropy and spin interactions are continuously tuned by the chemical composition. For the intermediate concentration all magnetic excitations are substantial broadened suggesting that disorder plays a key role in this species. For the two end-compounds, excitations remain sharp.
Simulating the dynamics of many-body quantum systems is believed to be one of the first fields that quantum computers can show a quantum advantage over classical computers. Noisy intermediate-scale quantum (NISQ) algorithms aim at effectively using the currently available quantum hardware. For quantum simulation, various types of NISQ algorithms have been proposed with individual advantages as well as challenges. In this work, we propose a new algorithm, truncated Taylor quantum simulator (TTQS), that shares the advantages of existing algorithms and alleviates some of the shortcomings. Our algorithm does not have any classical-quantum feedback loop and bypasses the barren plateau problem by construction. The classical part in our hybrid quantum-classical algorithm corresponds to a quadratically constrained quadratic program (QCQP) with a single quadratic equality constraint, which admits a semidefinite relaxation. The QCQP based classical optimization was recently introduced as the classical step in quantum assisted eigensolver (QAE), a NISQ algorithm for the Hamiltonian ground state problem. Thus, our work provides a conceptual unification between the NISQ algorithms for the Hamiltonian ground state problem and the Hamiltonian simulation. We recover differential equation-based NISQ algorithms for Hamiltonian simulation such as quantum assisted simulator (QAS) and variational quantum simulator (VQS) as particular cases of our algorithm. We test our algorithm on some toy examples on current cloud quantum computers. We also provide a systematic approach to improve the accuracy of our algorithm.
Recent spectropolarimetric surveys of bright, hot stars have found that ~10% of OB-type stars contain strong (mostly dipolar) surface magnetic fields (~kG). The prominent paradigm describing the interaction between the stellar winds and the surface magnetic field is the magnetically confined wind shock (MCWS) model. In this model, the stellar wind plasma is forced to move along the closed field loops of the magnetic field, colliding at the magnetic equator, and creating a shock. As the shocked material cools radiatively it will emit X-rays. Therefore, X-ray spectroscopy is a key tool in detecting and characterizing the hot wind material confined by the magnetic fields of these stars. Some B-type stars are found to have very short rotational periods. The effects of the rapid rotation on the X-ray production within the magnetosphere have yet to be explored in detail. The added centrifugal force due to rapid rotation is predicted to cause faster wind outflows along the field lines, leading to higher shock temperatures and harder X-rays. However, this is not observed in all rapidly rotating magnetic B-type stars. In order to address this from a theoretical point of view, we use the X-ray Analytical Dynamical Magnetosphere (XADM) model, originally developed for slow rotators, with an implementation of new rapid rotational physics. Using X-ray spectroscopy from ESA's XMM-Newton space telescope, we observed 5 rapidly rotating B-type stars to add to the previous list of observations. Comparing the observed X-ray luminosity and hardness ratio to that predicted by the XADM allows us to determine the role the added centrifugal force plays in the magnetospheric X-ray emission of these stars.