ShantanuT01/DACTYL-Pretraining huggingface dataset:
We report a first-principles study of the driven dissipative dynamics for Kerr oscillators in the mesoscopic regime. This regime is characterized by large Kerr nonlinearity, realized here using the nonlinear kinetic inductance of a large array of Josephson junctions. The experimentally measured nonlinear resonance lineshapes of the junction array modes show significant deviations from steady-state numerical predictions, and necessitate time-dependent numerical simulations indicative of strong measurement-induced dephasing in the system arising from the large cross-Kerr effect between array modes. Analytical and numerical calculations of switching rate corroborate this by showing the emergence of a slow time scale, which is much longer than the linear decay rate and is set by fluctuation-induced switching times in the bistable regime. Furthermore, our analysis shows that the usual quantum-activated escape treatment is inadequate for prediction of the switching rates at large frequency shifts caused by strong nonlinearities, necessitating a quantum treatment that utilizes the full system Liouvillian. Based on our analysis, we identify a universal crossover parameter that delineates the regimes of validity of semiclassical and quantum descriptions, respectively. Our work shows how dynamical switching effects in strongly nonlinear systems provide a platform to study quantum-to-classical transitions.
Covariant first and second quantization of the free d=4 massless superparticle are implemented with the introduction of purely gauge auxiliary spinor Lorentz harmonics. It is shown that the general solution of the condition of maslessness is a sum of two independent chiral superfields with each of them corresponding to finite superspin. A translationally covariant, in general bijective correspondence between harmonic and massless superfields is constructed. By calculation of the commutation function it is shown that in the considered approach only harmonic fields with correct connection between spin and statistics and with integer negative homogeneity index satisfy the microcausality condition. It is emphasized that harmonic fields that arise are reducible at integer points. The index spinor technique is used to describe infinite-component fields of finite spin; the equations of motion of such fields are obtained, and for them Weinberg's theorem on the connection between massless helicity particles and the type of nongauge field that describes them is generalized.
Electricity consumption forecasting has important implications for the mineral companies on guiding quarterly work, normal power system operation, and the management. However, electricity consumption prediction for the mineral company is different from traditional electricity load prediction since mineral company electricity consumption can be affected by various factors (e.g., ore grade, processing quantity of the crude ore, ball milling fill rate). The problem is non-trivial due to three major challenges for traditional methods: insufficient training data, high computational cost and low prediction accu-racy. To tackle these challenges, we firstly propose a Regressive Convolution Neural Network (RCNN) to predict the electricity consumption. While RCNN still suffers from high computation overhead, we utilize RCNN to extract features from the history data and Regressive Support Vector Machine (SVR) trained with the features to predict the electricity consumption. The experimental results show that the proposed RCNN-SVR model achieves higher accuracy than using the traditional RNN or SVM alone. The MSE, MAPE, and CV-RMSE of RCNN-SVR model are 0.8564, 1.975%, and 0.0687% respectively, which illustrates the low predicting error rate of the proposed model.
We briefly discuss five topics in Precision Electroweak Physics: i) the recently proposed Effective Scheme of Renormalization, ii) evidence for electroweak bosonic corrections derived from the radiative correction Delta_r_eff, iii) an approach to estimate the scale of new physics in a hypothetical Higgs-less scenario, iv) simple and accurate formulae for s^2_eff, M_W, Gamma_l, and their physical applications, v) a recent proposal concerning the field renormalization constant for unstable particles.
Our first goal in this work is to study general and model-independent properties of cyclic cosmologies. The large number of studies of bouncing cosmologies and different cyclic scenarios published recently calls for a proper understanding of the universal properties of cyclic models. We thus first review and further elaborate the common physical and geometrical properties of various classes of cyclic models and then discuss how cyclic Universe can be treated as a dynamic system. We then discuss how two theorems from dynamic systems analysis can be used to ensure the existence of cyclic cosmological solutions under certain conditions on the field equations. After this we proceed towards our second goal which is the application of the obtained results to different frameworks of modified gravity theories: $f(R)$ gravity, dynamic dark energy and $f(T)$ gravity. We discuss the general requirements for the existence of cyclic solutions in these theories and also obtain various examples of cyclic cosmologies, while discussing their basic properties.
We study the formation of singularity for the Euler-Poisson system equipped with the Boltzmann relation, which describes the dynamics of ions in an electrostatic plasma. In general, it is known that smooth solutions to nonlinear hyperbolic equations fail to exist globally in time. We establish criteria for $C^1$ blow-up of the Euler-Poisson system, both for the isothermal and pressureless cases. In particular, our blow-up condition for the presureless model does not require that the gradient of velocity is negatively large. In fact, our result particularly implies that the smooth solutions can break down even if the gradient of initial velocity is trivial. For the isothermal case, we prove that smooth solutions leave $C^1$ class in a finite time when the gradients of the Riemann functions are initially large.
We exactly calculate the quasinormal frequencies of the electromagnetic and Klein-Gordon perturbations propagating in a five-dimensional dilatonic black hole. Furthermore we exactly find the quasinormal frequencies of the massive Dirac field. Using these results we study the linear stability of this black hole. We compare our results for the quasinormal frequencies and for the linear stability of the five-dimensional black hole with those already published.
Weakly supervised instance segmentation reduces the cost of annotations required to train models. However, existing approaches which rely only on image-level class labels predominantly suffer from errors due to (a) partial segmentation of objects and (b) missing object predictions. We show that these issues can be better addressed by training with weakly labeled videos instead of images. In videos, motion and temporal consistency of predictions across frames provide complementary signals which can help segmentation. We are the first to explore the use of these video signals to tackle weakly supervised instance segmentation. We propose two ways to leverage this information in our model. First, we adapt inter-pixel relation network (IRN) to effectively incorporate motion information during training. Second, we introduce a new MaskConsist module, which addresses the problem of missing object instances by transferring stable predictions between neighboring frames during training. We demonstrate that both approaches together improve the instance segmentation metric $AP_{50}$ on video frames of two datasets: Youtube-VIS and Cityscapes by $5\%$ and $3\%$ respectively.
The present paper examines the influence of a nonlinear relationship between the local oxygen-vacancy concentration and the local resistivity on resistive switching effects in complex oxides. The continuity equation has been used as a model for the motion of oxygen vacancies when a periodic time-dependent electrical current is applied. The question of endurance of the switching cycles is discussed. It is found that nonlinearity of the resistivity-concentration dependence enhances the endurance.
We consider a ferromagnetic Ising chain evolving under Kawasaki dynamics at zero temperature. We investigate the statistics of the metastable configurations in which the system gets blocked (statistics of energy, spin correlations, distribution of domain sizes). A systematic comparison is made with analytical predictions for the ensemble of all blocked configurations taken with equal a priori weights (Edwards approach).
We develop a stochastic analysis for a Gaussian process $X$ with singular covariance by an intrinsic procedure focusing on several examples such as covariance measure structure processes, bifractional Brownian motion, processes with stationary increments. We introduce some new spaces associated with the self-reproducing kernel space and we define the Paley-Wiener integral of first and second order even when $X$ is only a square integrable process continuous in $L^2$. If $X$ has stationary increments, we provide necessary and sufficient conditions so that its paths belong to the self-reproducing kernel space. We develop Skorohod calculus and its relation with symmetric-Stratonovich type integrals and two types of It\^o's formula. One of Skorohod type, which works under very general (even very singular) conditions for the covariance; the second one of symmetric-Stratonovich type, which works, when the covariance is at least as regular as the one of a fractional Brownian motion of Hurst index equal to $H = \frac{1}{4}$.
The first part reviews the working mechanisms, capabilities and performance of axion helioscopes, including the achieved results so far. The 2nd part is observationally driven. New simulation results obtained with the Geant4 code reconstruct spectral shape of solar X-ray spectra, and their isotropic emission and lateral size. The derived rst mass of the axion(-like) particles is ~10meV. The axion interaction with magnetic field gradient is a generic theoretical suggestion that could reconcile present limits with relevant solar X-ray activity. A short outlook of the experimentally expanding solar axion field is given.
We develop a versatile and analytically solvable potential which fairly reproduces the combined potential of an $\alpha+$nucleus system resulting from both the attractive nuclear and repulsive electrostatic potentials. The potential is expressed in terms of the radial position, mass and proton number of the $\alpha$-particle and the daughter nucleus and certain parameters governing the depth, height and steepness of the barrier. The potential generated is typically a pocket near the origin and a barrier adjacent to it. The Schr\"odinger equation with the above mentioned potential is then solved for the wave function. This potential produces discrete positive energy quasibound state known as resonance state. By matching the wave function and its derivative with the regular Coulomb wave function $F_0$ and irregular Coulomb wave function $G_0$, we obtain the S-matrix analytically. The resonance is obtained from the pole in complex energy plane which gives the width of the corresponding time of decay through the imaginary part of the energy pole position. We make a comparative study of the measured half-lives of various nuclei with the calculated half-lives. The calculated values of half-lives closely match with the corresponding experimental results.
We propose and study a concept of renormalized solution to the problem $\Delta_p u=0$ in $\mathbb{R}^N_+$, $|\nabla u|^{p-2}u_{\nu} + g(u) = \mu$ on $\partial\mathbb{R}^N_+$, where $1<p\leq N$, $N\geq 2$, $\mathbb{R}^N_+=\left\lbrace(x',x_N):x'\in\mathbb{R}^{N-1}, x_N>0\right\rbrace $, $u_{\nu}$ is the normal derivative of $u$, $\mu$ is a bounded Radon measure, and $g:\mathbb{R}\rightarrow\mathbb{R}$ is a nonlinear term. We develop stability results and, using the symmetry of the domain, apriori estimates on hyperplanes, and potential methods, we obtain several existence results. In particular, we show existence of solutions for problems with nonlinear terms of the absorption type in both subcritical and supercritical cases. Regarding the problem with source, we study the power nonlinearity $g(u)=-u^q$, showing existence in the supercritical case, and nonexistence in the subcritical one. We also give a characterization of removable sets when $\mu\equiv 0$ and $g(u)=-u^q$ in the supercritical case. We remark that this work is motivated by similar results obtained for the problem $-\Delta_p u + g(x,u)=\mu$ in bounded domains.
The variety of gamma-ray burst phenomenology could be largely attributable to differences in the opening angle of an isotropic outflow or to a standard type of event viewed from different orientations. Motivated by this currently popular idea, we study the effects of varying the energy per unit solid angle in the unsteady expelled outflow by an increase either in the bulk Lorentz factor or in the baryon loading. We apply these models to interpret the observed correlations between variability, luminosity and spectral peak energy and find that while the latter scenario fails to provide a good description, bursts produced by collisions between similar mass shells but with increasingly large Lorentz factors are both more variable and have larger peak spectral energies. We present detailed internal shock calculations confirming this interpretation and discuss the roles various timescales, radii and the optical thickness of the wind play in determining this wide range of behaviors. Finally, we discuss the variety of scenarios in which large variations of the source expansion velocity are naturally expected.
We prove that the functional renormalization group flow equation admits a perturbative solution and show explicitly the scheme transformation that relates it to the standard schemes of perturbation theory. We then define a universal scheme within the functional renormalization group.
Studying the nature and origin of the intergalactic magnetic field (IGMF) is an outstanding problem of cosmology. Measuring Faraday rotation would be a promising method to explore the IGMF in the large-scale structure (LSS) of the universe. We investigated the Faraday rotation measure (RM) due to the IGMF in filaments of galaxies using simulations for cosmological structure formation. We employed a model IGMF based on turbulence dynamo in the LSS of the universe; it has an average strength of $< B > \sim 10$ nG and a coherence length of several $\times\ 100\ h^{-1}$ kpc in filaments. With the coherence length smaller than path length, the inducement of RM would be a random walk process, and we found that the resultant RM is dominantly contributed by the density peak along line of sight. The rms of RM through filaments at the present universe was predicted to be $\sim 1\ {\rm rad\ m^{-2}}$. In addition, we predicted that the probability distribution function of $|{\rm RM}|$ through filaments follows the log-normal distribution, and the power spectrum of RM in the local universe peaks at a scale of $\sim 1\ h^{-1}$ Mpc. Our prediction of RM could be tested with future instruments.
We find 132 face-on and low inclination galaxies with central star formation driven biconical gas outflows (FSFB) in the SDSS MaNGA (Mapping Nearby Galaxies at APO) survey. The FSFB galaxies show either double peaked or broadened emission line profiles at their centres. The peak and maximum outflow velocities are 58 and 212 km/s, respectively. The gas velocity dispersion reveals a mild dependence on the central star formation surface density compatible with models of gas dispersion powered by the Jeans instability in gas clumps or by gas turbulence dissipation. We estimate the gas outflow rate and conclude that the central gas depletion time does not depend on galactic mass. In turn, the ratio of the gas outflow rate to the gas consumption rate by the star formation is low in massive galaxies and high in low-mass objects, while the star formation is a more rapid process of the gas consumption. We compare properties of the FSFB galaxies with a control sample of 375 comparison galaxies and find that the FSFB objects have high central concentration of star formation, and also younger central stellar population with respect to their periphery. We analysed the environment of the galaxies and identified nearby satellites and elements of low surface brightness structure. We see that many tidal-enhanced features that can be assigned to early and intermediate stages of galactic interaction are much more frequent in the FSFB galaxies with respect to the comparison sample. We conclude that the gas should be replenished via the accretion from small satellites.
For a simple digraph $G$, let $\beta(G)$ be the size of the smallest subset $X\subseteq E(G)$ such that $G-X$ has no directed cycles, and let $\gamma(G)$ be the number of unordered pairs of nonadjacent vertices in $G$. A digraph $G$ is called $m$-free if $G$ has no directed cycles of length at most $m$. This paper proves that $\beta(G)\leq \frac{1}{m-2}\gamma(G)$ for any $m$-free digraph $G$, which generalized some known results.
We analyze archival Ly$\alpha$ spectra of 12 "Green Pea" galaxies observed with the Hubble Space Telescope, model their Ly$\alpha$ profiles with radiative transfer models, and explore the dependence of Ly$\alpha$ escape fraction on various properties. Green Pea galaxies are nearby compact starburst galaxies with [OIII]$\lambda$5007 equivalent widths of hundreds of \AA. All 12 Green Pea galaxies in our sample show Ly$\alpha$ lines in emission, with a Ly$\alpha$ equivalent width distribution similar to high redshift Ly$\alpha$ emitters. Combining the optical and UV spectra of Green Pea galaxies, we estimate their Ly$\alpha$ escape fractions and find correlations between Ly$\alpha$ escape fraction and kinematic features of Ly$\alpha$ profiles. The escape fraction of Ly$\alpha$ in these galaxies ranges from 1.4% to 67%. We also find that the Ly$\alpha$ escape fraction depends strongly on metallicity and moderately on dust extinction. We compare their high-quality Ly$\alpha$ profiles with single HI shell radiative transfer models and find that the Ly$\alpha$ escape fraction anti-correlates with the derived HI column densities. Single shell models fit most Ly$\alpha$ profiles well, but not the ones with highest escape fractions of Ly$\alpha$. Our results suggest that low HI column density and low metallicity are essential for Ly$\alpha$ escape, and make a galaxy a Ly$\alpha$ emitter.
We show that mass parameter and radial coordinate values can be indirectly measured in thought experiments performed in Schwarzschild spacetime, without using the Newtonian limit of general relativity or approximations based on Euclidean geometry. Our approach involves different proper time quantifcations as well as solutions to systems of algebraic equations, and aims to strengthen the conceptual independence of general relativity from Newtonian gravity.
Applying a first-principles computational approach, we have systematically analyzed the effects of [2+2] cycloaddition oligomerization of fullerene C60 chains on their junction electronic and charge transport properties. For hypothetical infinite C60 chains, we first establish that the polymerization can in principle increase conductance by several orders of magnitude due to the strong orbital hybridizations and band formation. On the other hand, our simulations of the constant-height scanning tunneling microscope (STM) configuration shows that, in agreement with the recent experimental conclusion, the junction electronic structure and device characteristics are virtually unaffected by the C60 chain oligomerization. We further predict that the switching characteristics including even the ON/OFF-state assignment will sensitively depend on the substrate metal species due to the Fermi-level pinning at the substrate-side contact and the subsequent energy level bending toward the STM tip-side contact. We finally demonstrate that a force-feedbacked nanoelectromechanical approach in which both of the C60-electrode distances are kept at short distances before and after switching operations can achieve a metal-independent and significantly improved switching performance due to the Fermi-level pinning in both contacts and the large intrinsic conductance switching capacity of the C60 chain oligomerization.
The scalar and vectorial self energies obtained through QCD sum rules are introduced in the Quantum Hadrodynamics (QHD) equations. This QHD and QCD mixing show us that the effect of the density on the coupling constants is very small.
The pion scalar form factor along with all existing S-wave iso-scalar $\pi\pi$-scattering phase shift data in the elastic region up to $1 {\rm GeV}^2$ are applied for a determination of the $f_0(500)$ and $f_0(980)$ meson parameters $m_{f_0(500)}=(360\pm33){\rm MeV}$, $\Gamma_{f_0(500)}=(587\pm 85){\rm MeV}$ and $m_{f_0(980)}=(957\pm77) {\rm MeV}$, $\Gamma_{f_0(980)}=(164\pm142){\rm MeV}$ in a model independent way.
The 2-colouring discrepancy of arithmetic progressions is a well-known problem in combinatorial discrepancy theory. In 1964, Roth proved that if each integer from 0 to N is coloured red or blue, there is some arithmetic progression in which the number of reds and the number of blues differ by at least (1/20) N^{1/4}. In 1996, Matousek and Spencer showed that this estimate is sharp up to a constant. The analogous question for homogeneous arithmetic progressions (i.e., the ones containing 0) was raised by Erdos in the 1930s, and it is still not known whether the discrepancy is unbounded. However, it is easy to construct partial colourings with density arbitrarily close to 1 such that all homogeneous arithmetic progressions have bounded discrepancy.   A related problem concerns the discrepancy of quasi-progressions. A quasi-progression consists of successive multiples of a real number, with each multiple rounded down to the nearest integer. In 1986, Beck showed that given any 2-colouring, the quasi-progressions corresponding to almost all real numbers in (1, \infty) have discrepancy at least log* N, the inverse of the tower function. We improve the lower bound to (log N)^{1/4 - o(1)}, and also show that there is some quasi-progression with discrepancy at least (1/50) N^{1/6}. Our results remain valid even if the 2-colouring is replaced by a partial colouring of positive density.
We present here maximum timings of RR Lyrae stars observed in 2016 and 2017 by VSOLJ member Kenji Hirosawa. The calculation of the time of maximum from the measurements provided by the observer have been made in the frame of the GEOS RR Lyr survey.
An effective-Lagrangian framework for K Sigma photoproduction from the proton is presented. The proposed model is applicable at forward kaon angles and photon lab energies from threshold up to 16 GeV. The high-energy part of the p(gamma,K^+)Sigma^0 and p(gamma,K^0)Sigma^+ amplitudes is expressed in terms of Regge-trajectory exchange in the t channel. By supplementing this Regge background with a number of s-channel resonances, the model is extended towards the resonance region. The resulting ``Regge-plus-resonance'' (RPR) approach has the advantage that the background contributions involve only a few parameters, which can be largely constrained by the high-energy data. This work compares various implementations of the RPR model, and explores which resonance contributions are required to fit the data presently at hand. It is demonstrated that, through the inclusion of one K and two K* trajectories, the RPR framework provides an efficient and unified description of the K^+ Sigma^0 and K^0 Sigma^+ photoproduction channels over an extensive energy range.