ShantanuT01/DACTYL-Pretraining huggingface dataset:
A critical review of frequency-shift phenomena a la Doppler effect is presented. The importance of Fermi's theory of 1932 is pointed out, and it is argued that there exists a gap in our understanding of this phenomena at a fundamental level. Alternative mechanism in terms of photon number oscillations is suggested for polarization changing experiments. The physical reality of single photon is revisited, and a possible experimental scheme to test the alternative mechanism is suggested.
We present the results of a 6.1 square degree survey for clusters of galaxies via their Sunyaev- Zel'dovich (SZ) effect at 31 GHz. From late 2005 to mid 2007 the Sunyaev-Zel'dovich Array (SZA) observed four fields of roughly 1.5 square degrees each. One of the fields shows evidence for significant diffuse Galactic emission, and we therefore restrict our analysis to the remaining 4.4 square degrees. We estimate the cluster detectability for the survey using mock observations of simulations of clusters of galaxies; and determine that, at intermediate redshifts (z ~ 0.8), the survey is 50% complete to a limiting mass (M200 rho mean) of ~ 6.0 x 10^14M_{solar}, with the mass limit decreasing at higher redshifts. We detect no clusters at a significance greater than 5 times the RMS noise level in the maps, and place an upper limit on \sigma_8, the amplitude of mass density fluctuations on a scale of 8h^-1 Mpc, of 0.84 + 0.07 at 95% confidence, where the uncertainty reflects calibration and systematic effects. This result is consistent with estimates from other cluster surveys and CMB anisotropy experiments.
In this work, we introduce a method and present an improved neural work to perform product re-identification, which is an essential core function of a fully automated product defect detection system. Our method is based on feature distance. It is the combination of feature extraction neural networks, such as VGG16, AlexNet, with an image search engine - Vearch. The dataset that we used to develop product re-identification systems is a water-bottle dataset that consists of 400 images of 18 types of water bottles. This is a small dataset, which was the biggest challenge of our work. However, the combination of neural networks with Vearch shows potential to tackle the product re-identification problems. Especially, our new neural network - AlphaAlexNet that a neural network was improved based on AlexNet could improve the production identification accuracy by four percent. This indicates that an ideal production identification accuracy could be achieved when efficient feature extraction methods could be introduced and redesigned for image feature extractions of nearly identical products. In order to solve the biggest challenges caused by the small size of the dataset and the difficult nature of identifying productions that have little differences from each other. In our future work, we propose a new roadmap to tackle nearly-identical production identifications: to introduce or develop new algorithms that need very few images to train themselves.
The cosmic microwave background (CMB) serves as a backlight to large-scale structure during the epoch of reionization, where Thomson scattering gives rise to temperature anisotropies on small angular scales from the kinetic Sunyaev Zel'dovich (kSZ) effect. In this paper, we demonstrate that the technique of kSZ tomography (velocity reconstruction), based on cross correlations between CMB temperature and 21cm surveys, can significantly improve constraints on models of inhomogeneous reionization and provide information about large-scale modes that are poorly characterized by 21cm measurements themselves due to foreground contamination.
Many astronomical sources produce transient phenomena at radio frequencies, but the transient sky at low frequencies (<300 MHz) remains relatively unexplored. Blind surveys with new widefield radio instruments are setting increasingly stringent limits on the transient surface density on various timescales. Although many of these instruments are limited by classical confusion noise from an ensemble of faint, unresolved sources, one can in principle detect transients below the classical confusion limit to the extent that the classical confusion noise is independent of time. We develop a technique for detecting radio transients that is based on temporal matched filters applied directly to time series of images rather than relying on source-finding algorithms applied to individual images. This technique has well-defined statistical properties and is applicable to variable and transient searches for both confusion-limited and non-confusion-limited instruments. Using the Murchison Widefield Array as an example, we demonstrate that the technique works well on real data despite the presence of classical confusion noise, sidelobe confusion noise, and other systematic errors. We searched for transients lasting between 2 minutes and 3 months. We found no transients and set improved upper limits on the transient surface density at 182 MHz for flux densities between ~20--200 mJy, providing the best limits to date for hour- and month-long transients.
We report the results of a multi-year spectroscopic and photometric monitoring campaign of two luminous quasars, PG~0923+201 and PG~1001+291, both located at the high-luminosity end of the broad-line region (BLR) size-luminosity relation with optical luminosities above $10^{45}~{\rm erg~s^{-1}}$. PG~0923+201 is for the first time monitored, and PG~1001+291 was previously monitored but our campaign has a much longer temporal baseline. We detect time lags of variations of the broad H$\beta$, H$\gamma$, Fe {\sc ii} lines with respect to those of the 5100~{\AA} continuum. The velocity-resolved delay map of H$\beta$ in PG~0923+201 indicates a complicated structure with a mix of Keplerian disk-like motion and outflow, and the map of H$\beta$ in PG~1001+291 shows a signature of Keplerian disk-like motion. Assuming a virial factor of $f_{\rm BLR}=1$ and FWHM line widths, we measure the black hole mass to be $118_{-16}^{+11}\times 10^7 M_{\odot}$ for PG~0923+201 and $3.33_{-0.54}^{+0.62}\times 10^7 M_{\odot}$ for PG~1001+291. Their respective accretion rates are estimated to be $0.21_{-0.07}^{+0.06} \times L_{\rm Edd}\,c^{-2}$ and $679_{-227}^{+259}\times L_{\rm Edd}\,c^{-2}$, indicating that PG~0923+201 is a sub-Eddington accretor and PG~1001+291 is a super-Eddington accretor. While the H$\beta$ time lag of PG~0923+201 agrees with the size-luminosity relation, the time lag of PG~1001+291 shows a significant deviation, confirming that in high-luminosity AGN the BLR size depends on both luminosity and Eddington ratio. Black hole mass estimates from single AGN spectra will be over-estimated at high luminosities and redshifts if this effect is not taken into account.
In this paper, we use the theory of Riordan matrices to introduce the notion of a Riordan graph. The Riordan graphs are a far-reaching generalization of the well known and well studied Pascal graphs and Toeplitz graphs, and also some other families of graphs. The Riordan graphs are proved to have a number of interesting (fractal) properties, which can be useful in creating computer networks with certain desirable features, or in obtaining useful information when designing algorithms to compute values of graph invariants. The main focus in this paper is the study of structural properties of families of Riordan graphs obtained from infinite Riordan graphs, which includes a fundamental decomposition theorem and certain conditions on Riordan graphs to have an Eulerian trail/cycle or a Hamiltonian cycle. We will study spectral properties of the Riordan graphs in a follow up paper.
Friezes with coefficients are maps assigning numbers to the edges and diagonals of a regular polygon such that all Ptolemy relations for crossing diagonals are satisfied. Among these, the classic Conway-Coxeter friezes are the ones where all values are natural numbers and all edges have value 1. Every subpolygon of a Conway-Coxeter frieze yields a frieze with coefficients over the natural numbers. In this paper we give a complete arithmetic criterion for which friezes with coefficients appear as subpolygons of Conway-Coxeter friezes. This generalizes a result of our earlier paper with Peter Jorgensen from triangles to subpolygons of arbitrary size.
We introduce a large family of combinatorial objects, called standard puzzles, defined by very simple rules. We focus on the standard puzzles for which the enumeration problems can be solved by explicit formulas or by classical numbers, such as binomial coefficients, Fibonacci numbers, tangent numbers, Catalan numbers, $\ldots$
We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of differential equations, we expand the integrals in powers of the dimensional regulator $\epsilon$ and determine the expansion coefficients in terms of generalized harmonic polylogarithms of two dimensionless variables through to weight four.
This article concerns a class of elliptic equations on Carnot groups depending on one real positive parameter and involving a subcritical nonlinearity (for the critical case we refer to G. Molica Bisci and D. Repov\v{s}, Yamabe-type equations on Carnot groups, Potential Anal. 46:2 (2017), 369-383; arXiv:1705.10100 [math.AP]). As a special case of our results we prove the existence of at least one nontrivial solution for a subelliptic equation defined on a smooth and bounded domain $D$ of the Heisenberg group $\mathbb{H}^n=\mathbb{C}^n\times \mathbb{R}$. The main approach is based on variational methods.
The deuteron-proton elastic scattering has been studied in the multiple scattering expansion formalism. The essential attention has been given to such relativistic problem as a deuteron wave function in a moving frame and transformation of spin states due to Wigner rotation. Parameterization of the nucleon-nucleon $t$-matrix has been used to take the off-energy shell effects into account. The vector, $A_y,$ and tensor, $A_{yy}$, analyzing powers of the deuteron have been calculated at two deuteron kinetic energies: 395 MeV and 1200 MeV. The obtained results are compared with the experimental data.
In this work, we present a comprehensive study of the low energy optical magnetic response of the skyrmionic Mott insulator Cu$_2$OSeO$_3$ via high resolution time-domain THz spectroscopy. In zero field, a new magnetic excitation not predicted by spin-wave theory with frequency $f$ = 2.03 THz is observed and shown, with accompanying time-of-flight neutron scattering experiments, to be a zone folded magnon from the $\mathrm{R}$ to $\mathrm{\Gamma}$ points of the Brillouin zone. Highly sensitive polarimetry experiments performed in weak magnetic fields, $\mu_0$H $<$ 200 mT, observe Faraday and Kerr rotations which are proportional to the sample magnetization, allowing for optical detection of the skyrmion phase and construction of a magnetic phase diagram. From these measurements, we extract a critical exponent of $\beta$ = 0.35 $\pm$ 0.04, in good agreement with the expected value for the 3D Heisenberg universality class of $\beta$ = 0.367. In large magnetic fields, $\mu_0$H $>$ 5 T, we observe the magnetically active uniform mode of the ferrimagnetic field polarized phase whose dynamics as a function of field and temperature are studied. In addition to extracting a $g_\text{eff}$ = 2.08 $\pm$ 0.03, we observe the uniform mode to decay through a non-Gilbert damping mechanism and to possesses a finite spontaneous decay rate, $\Gamma_0$ $\approx$ 25 GHz, in the zero temperature limit. Our observations are attributed to Dzyaloshinkii-Moriya interactions, which have been proposed to be exceptionally strong in Cu$_2$OSeO$_3$ and are expected to impact the low energy magnetic response of such chiral magnets.
Recent progress concerning regularization of supersymmetric theories is reviewed. Dimensional reduction is reformulated in a mathematically consistent way, and an elegant and general method is presented that allows to study the supersymmetry-invariance of dimensional reduction in an easy manner. This method is applied to several supersymmetry identities at the one- and two-loop level, and thus the extent to which dimensional reduction is known to preserve supersymmetry is significantly enlarged.
It was recently shown that the bolometric light curves of type II supernovae (SNe) allow an accurate and robust measurement of the product of the radiation energy in the ejecta, $E_r$, and the time since the explosion, $t$, at early phases ($t\lesssim 10d$) of the homologous expansion. This observable, denoted here $ET \equiv E_rt$ is constant during that time and depends only on the progenitor structure and explosion energy. We use a 1D hydrodynamic code to find $ET$ of simulated explosions of 145 red supergiant progenitors obtained using the stellar evolution code MESA, and relate this observable to the properties of the progenitor and the explosion energy. We show that $ET$ probes only the properties of the envelope (velocity, mass and initial structure), similarly to other observables that rely on the photospheric phase emission. Nevertheless, for explosions where the envelope dominates the ejected mass, $M_{env}/M_{ej} \gtrsim 0.6$, $ET$ is directly related to the explosion energy $E_{exp}$ and ejected mass $M_{ej}$ through the relation $ET \approx 0.15 E_{exp}^{1/2} R_* M_{ej}^{1/2}$, where $R_*$ is the progenitor radius, to an accuracy better than $30\%$. We also provide relations between $ET$ and the envelope properties that are accurate (to within 20\%) for all the progenitors in our sample, including those that lost most of their envelope. We show that when the envelope velocity can be reasonably measured by line shifts in observed spectra, the envelope is directly constrained from the bolometric light curve (independent of $E_{exp}$). We use that to compare observations of 11 SNe with measured $ET$ and envelope velocity to our sample of numerical progenitors. This comparison suggests that many SNe progenitors have radii that are $\lesssim 500~R_\odot$. In the framework of our simulations this indicates, most likely, a rather high value of the mixing length parameter.
Localized energy estimates for the wave equation have been increasingly used to prove various other dispersive estimates. This article focuses on proving such localized energy estimates on $(1+4)$-dimensional Myers-Perry black hole backgrounds with small angular momenta. The Myers-Perry space-times are generalizations of higher dimensional Kerr backgrounds where additional planes of rotation are availabile while still maintaining axial symmetry. Once it is determined that all trapped geodesics have constant $r$, the method developed by Tataru and the fourth author, which perturbs off of the Schwarzschild case by using a pseudodifferential multiplier, can be adapted.
We investigate various questions concerning the reciprocal sum of divisors, or prime divisors, of the Mersenne numbers $2^n-1$. Conditional on the Elliott-Halberstam Conjecture and the Generalized Riemann Hypothesis, we determine $\max_{n\le x} \sum_{p \mid 2^n-1} 1/p$ to within $o(1)$ and $\max_{n\le x} \sum_{d\mid 2^n-1}1/d$ to within a factor of $1+o(1)$, as $x\to\infty$. This refines, conditionally, earlier estimates of Erd\H{o}s and Erd\H{o}s-Kiss-Pomerance. Conditionally (only) on GRH, we also determine $\sum 1/d$ to within a factor of $1+o(1)$ where $d$ runs over all numbers dividing $2^n-1$ for some $n\le x$. This conditionally confirms a conjecture of Pomerance and answers a question of Murty-Rosen-Silverman. Finally, we show that both $\sum_{p\mid 2^n-1} 1/p$ and $\sum_{d\mid 2^n-1}1/d$ admit continuous distribution functions in the sense of probabilistic number theory.
As the number of qubits in nascent quantum processing units increases, the connectorized RF (radio frequency) analog circuits used in first generation experiments become exceedingly complex. The physical size, cost and electrical failure rate all become limiting factors in the extensibility of control systems. We have developed a series of compact RF mixing boards to address this challenge by integrating I/Q quadrature mixing, IF(intermediate frequency)/LO(local oscillator)/RF power level adjustments, and DC (direct current) bias fine tuning on a 40 mm $\times $ 80 mm 4-layer PCB (printed circuit board) board with EMI (electromagnetic interference) shielding. The RF mixing module is designed to work with RF and LO frequencies between 2.5 and 8.5 GHz. The typical image rejection and adjacent channel isolation are measured to be $\sim$27 dBc and $\sim$50 dB. By scanning the drive phase in a loopback test, the module short-term amplitude and phase linearity are typically measured to be 5$\times$10$^{-4}$ (V$_{\mathrm{pp}}$/V$_{\mathrm{mean}}$) and 1$\times$10$^{-3}$ radian (pk-pk). The operation of RF mixing board was validated by integrating it into the room temperature control system of a superconducting quantum processor and executing randomized benchmarking characterization of single and two qubit gates. We measured a single-qubit process infidelity of $9.3(3) \times 10^{-4}$ and a two-qubit process infidelity of $2.7(1) \times 10^{-2}$.
We suggest a way of confining quasiparticles by an external potential in a small region of a graphene strip. Transversal electron motion plays a crucial role in this confinement. Properties of thus obtained graphene quantum dots are investigated theoretically for different types of the boundary conditions at the edges of the strip. The (quasi)bound states exist in all systems considered. At the same time, the dependence of the conductance on the gate voltage carries an information about the shape of the edges.
We discuss the spectral problem for integrable superstrings on generically twisted AdS_5 x S^5, meaning all its orbifolds and TsT transformed versions. We explicitly give the asymptotic description of these theories through a twisted transfer matrix, and carefully match the geometric deformations with twists allowed by integrability. We then discuss the mirror TBA equations that describe these theories at finite size. This unifies the treatment of various specific deformations previously considered in this setting, and extends it to completely general twists.
Realizing a part of the Derived Deformation Theory program, we construct a "derived" analog of the Grothendieck's Quot scheme parametrizing subsheaves in a given coherent sheaf F on a smooth projective variety X. This analog is a differential graded manifold RQuot_h(F) (so it is always smooth in an appropriate sense) whose tangent space at a point represented by a subsheaf K in F, is a cochain complex quasiisomorphic to RHom(K, F/K).
We investigate the orbifold limits of string theory compactifications with geometric and non-geometric fluxes. Exploiting the connection between internal fluxes and structure constants of the gaugings in the reduced supergravity theory, we can identify the types of fluxes arising in certain classes of freely-acting symmetric and asymmetric orbifolds. We give a general procedure for deriving the gauge algebra of the effective gauged supergravity using the exact CFT description at the orbifold point. We find that the asymmetry is, in general, related to the presence of non-geometric Q- and R- fluxes. The action of T-duality is studied explicitly on various orbifold models and the resulting transformation of the fluxes is derived. Several explicit examples are provided, including compactifications with geometric fluxes, Q-backgrounds (T-folds) and R-backgrounds. In particular, we present an asymmetric Z4xZ2 orbifold in which all geometric and non-geometric fluxes {\omega}, H, Q, R are turned on simultaneously. We also derive the corresponding flux backgrounds, which are not in general T-dual to geometric ones, and may even simultaneously depend non-trivially on both the coordinates and their winding T-duals.
To study the role of torque in motility-induced phase separation (MIPS), we simulate a system of self-propelled particles whose shape varies smoothly from isotropic (disks/spheres) to weakly elongated (rods). We construct the phase diagrams of 2D active disks, 3D active spheres and 2D/3D active rods of aspect ratio $l/\sigma=2$. A stability analysis of the homogeneous isotropic phase allows us to predict the onset of MIPS based on the effective swimming speed and rotational diffusion of the particles. Both methods find suppression of MIPS as the particle shape is elongated. We propose a suppression mechanism based on the duration of collisions, and argue that this mechanism can explain both the suppression of MIPS found here for rodlike particles and the enhancement of MIPS found for particles with Vicsek interactions.
We have performed a careful investigation of the 74 candidate variable stars presented by Safanova & Stalin (2011). For this purpose we used our data base of imaging and light curves from Arellano Ferro et al. (2011) and Arellano Ferro et al. (2012). We find that two candidates are known variable stars, eight candidates were discovered first by Arellano Ferro et al. (2011) but would not have been known to Safanova & Stalin (2011) at the time of their paper submission, while four candidates are new variables. Three of the new variables are SX Phe type and one is a semi-regular red giant variable (SR type). We also tentatively confirm the presence of true variability in two other candidates and we are unable to investigate another four candidates because they are not in our data base. However, we find that the remaining 54 candidate variable stars are spurious detections where systematic trends in the light curves have been mistaken for true variability. We believe that the erroneous detections are caused by the adoption of a very low detection threshold used to identify these candidates.
We show that taking into account the interplay between perturbative and non-perturbative effects, the power-suppressed shift to the broadening distributions becomes B dependent, and the non-perturbative contribution to the mean values becomes proportional to 1/(Q\sqrt{\as(Q)}). The new theoretical treatment greatly improves the consistency of the phenomenology with the notion of the universality of confinement effects in jet shapes.