ShantanuT01/DACTYL-Pretraining huggingface dataset:
The strong coupling constants $g_{{\Sigma_{Q}\Lambda_{Q}\pi}}$ ($Q=b$ and $c$) are studied in the framework of the light cone QCD sum rules using the most general form of the baryonic currents. The predicted coupling constants are used to estimate the decay widths for the $\Sigma_{Q}\longrightarrow\Lambda_{Q}\pi$ decays which are compared with the predictions of the other approaches and existing experimental data.
The three theoretical and historical components of the Standard Model are the exact chiral gauge theory of weak interactions, electroweak unification, and the Higgs mechanism for spontaneous symmetry breaking. I put into historical perspective my 1958 invention of the first gauge theory of weak interactions, predicting weak neutral currents, and show how the fundamental differences between global and gauge symmetries and between partial flavour and exact gauge symmetries, emerged in the strong and weak interactions. Although renormalizability is necessary for theoretical consistency, electroweak unification was not necessary, in principle. An interesting difference appears between the $\sin^2{\theta_W}=0$ limit of the electroweak theory and the original $SU(2)_W$ gauge theory of weak interactions. While the electroweak mixing angle might have had any value (including zero), historically the value $\sin^2{\theta_W} \sim 0.3$ actually observed in weak neutral currents gave circumstantial support for the Standard Model and stimulated the search for $W-$ and $Z-$mesons.
We experimentally demonstrate an approach to scale up quantum devices by harnessing spin defects in the environment of a quantum probe. We follow this approach to identify, locate, and control two electron-nuclear spin defects in the environment of a single nitrogen-vacancy center in diamond. By performing spectroscopy at various orientations of the magnetic field, we extract the unknown parameters of the hyperfine and dipolar interaction tensors, which we use to locate the two spin defects and design control sequences to initialize, manipulate, and readout their quantum state. We finally create quantum coherence among the three electron spins, paving the way for the creation of genuine tripartite entanglement. This approach will be useful to assemble multi-spin quantum registers for applications in quantum sensing and quantum information processing.
We review a recent progress in constructing low-energy effective action in N=4 super Yang-Mills theories. Using harmonic superspace approach we consider N=4 SYM in terms of unconstrained N=2 superfield and apply N=2 background field method to finding effective action for N=4 SU(n) SYM broken down to U(n)$^{n-1}$. General structure of leading low-energy corrections to effective action is discussed.
Pentacenequinone (PnQ) impurities have been introduced into a pentacene source material in a controlled manner to quantify the relative effects of the impurity content on grain boundary structure and thin film nucleation. Atomic force microscopy (AFM) has been employed to directly characterize films grown using 0.0-7.5% PnQ by weight in the source material. Analysis of the distribution of capture zones areas of submonolayer islands as a function of impurity content shows that for large PnQ content the critical nucleus size for forming a Pn island is smaller than for low PnQ content. This result indicates a favorable energy for formation of Pn-PnQ complexes, which in turn suggests that the primary effect of PnQ on Pn mobility may arise from homogeneous distribution of PnQ defects.
A spectral line inversion code, Very Fast Inversion of the Stokes Vector (VFISV), has been used since May 2010 to infer the solar atmospheric parameters from the spectropolarimetric observations taken by the Helioseismic and Magnetic Imager (HMI) aboard the Solar Dynamics Observatory (SDO). The magnetic filling factor, the fraction of the surface with a resolution element occupied by magnetic field, is set to have a constant value of one in the current version of VFISV. This report describes an improved inversion strategy for the spectropolarimetric data observed with HMI for magnetic field strengths of intermediate values in areas spatially not fully resolved. The VFISV inversion code has been modified to enable inversion of the Stokes profiles with two different components: one magnetic and one non-magnetic. In this scheme, both components share the atmospheric components except for the magnetic field strength, inclination, and azimuth. In order to determine whether the new strategy is useful, we evaluate the inferred parameters inverted with one magnetic component (the original version of the HMI inversion) and with two components (the improved version) using a Bayesian analysis. In pixels with intermediate magnetic field strengths (e.g. plages), the new version provides statistically significant values of filling fraction and magnetic field vector. Not only does the fitting of the Stokes profile improve, but the inference of the magnetic parameters and line-of-sight velocity are obtained uniquely. The new strategy is also proven to be effective for mitigating the anomalous hemispheric bias in the east-west magnetic field component in moderate field regions.
Young binaries within dense molecular clouds are subject to dynamical friction from ambient gas. Consequently, their orbits decay, with both the separation and period decreasing in time. A simple analytic expression is derived for this braking torque. The derivation utilizes the fact that each binary acts as a quadrupolar source of acoustic waves. The acoustic disturbance has the morphology of a two-armed spiral and carries off angular momentum. From the expression for the braking torque, the binary orbital evolution is also determined analytically. This type of merger may help explain the origin of high-mass stars. If infrared dark clouds, with peak densities up to 10^7 cm^{-3}, contain low-mass binaries, those with separations less than 100 AU merge within about 10^5 yr. During the last few thousand years of the process, the rate of mechanical energy deposition in the gas exceeds the stars' radiative luminosity. Successive mergers may lead to the massive star formation believed to occur in these clouds.
We review recent work concerning topology changing phase transitions through black hole condensation in Type II string theory. We then also briefly describe a present study aimed at extending the known web of interconnections between Calabi-Yau manifolds. We show, for instance, that all 7555 Calabi-Yau hypersurfaces in weighted projective four space are mathematically connected by extremal transitions.
We present a new sample of active galactic nuclei (AGNs) identified using the catalog of the AKARI Mid-infrared(MIR) All-Sky Survey. Our MIR search has an advantage in detecting AGNs that are obscured at optical wavelengths due to extinction. We first selected AKARI 9micron excess sources with F(9micron)/F(K_S)>2 where K_S magnitudes were taken from the Two Micron All Sky Survey. We then obtained follow-up near-infrared spectroscopy with the AKARI/IRC, to confirm that the excess is caused by hot dust. We also obtained optical spectroscopy with the Kast Double Spectrograph on the Shane 3-m telescope at Lick Observatory. On the basis of on these observations, we detected hot dust with a characteristic temperature of ~500K in two luminous infrared galaxies. The hot dust is suspected to be associated with AGNs that exhibit their nonstellar activity not in the optical, but in the near- and mid-infrared bands, i.e., they harbor buried AGNs. The host galaxy stellar masses of 4-6 x 10^9 M_sun are small compared with the hosts in optically-selected AGN populations. These objects were missed by previous surveys, demonstrating the power of the AKARI MIR All-Sky Survey to widen AGN searches to include more heavily obscured objects. The existence of multiple dusty star clusters with massive stars cannot be completely ruled out with our current data.
A novel treatment of non-adiabatic couplings is proposed. The derivation starts from the long-known, but not well-known, fact that the wave function of the complete system of elctrons and nuclei can be written, without approximation, as a Born-Oppenheimer-type product of a nuclear wavefunction, X(R), and an electronic one, Phi_R(r), which depends parametrically on the nuclear configuration R. From the variational principle we deduce formally exact equations for Phi_R(r) and X(R). The algebraic structure of the exact nuclear equation coincides with the corresponding one in the adiabatic approximation. The electronic equation, however, contains terms not appearing in the adiabatic case, which couple the electronic and the nuclear wavefunctions and account for the electron-nuclear correlation beyond the Born-Oppenheimer level. It is proposed that these terms can be incorporated using an optimized local effective potential.
Iron tungstate (FeWO$_4$) and manganese tungstate (MnWO$_4$) belong to a family of wolframite-type materials that has applications in various areas, including supercapacitors, batteries, and multiferroics. A detailed understanding of bulk properties and defect physics in these transition-metal tungstates has been lacking, however, impeding possible improvement of their functional properties. Here, we report a first-principles study of FeWO$_4$ and MnWO$_4$ using screened hybrid density-functional calculations. We find that in both compounds the electronic structure near the band edges are predominantly the highly localized transition-metal $d$ states, which allows for the formation of both hole polarons at the Fe (Mn) sites and electron polarons at the W sites. The dominant native point defects in FeWO$_4$ (MnWO$_4$) under realistic synthesis conditions are, however, the hole polarons at the Fe (Mn) sites and negatively charged Fe (Mn) vacancies. The presence of low-energy and highly mobile polarons provides explanation for the good p-type conductivity observed in experiments and the ability of the materials to store energy via a pseudocapacitive mechanism.
Many imaging problems can be formulated as mapping problems. A general mapping problem aims to obtain an optimal mapping that minimizes an energy functional subject to the given constraints. Existing methods to solve the mapping problems are often inefficient and can sometimes get trapped in local minima. An extra challenge arises when the optimal mapping is required to be diffeomorphic. In this work, we address the problem by proposing a deep-learning framework based on the Quasiconformal (QC) Teichmuller theories. The main strategy is to learn the Beltrami coefficient (BC) that represents a mapping as the latent feature vector in the deep neural network. The BC measures the local geometric distortion under the mapping, with which the interpretability of the deep neural network can be enhanced. Under this framework, the diffeomorphic property of the mapping can be controlled via a simple activation function within the network. The optimal mapping can also be easily regularized by integrating the BC into the loss function. A crucial advantage of the proposed framework is that once the network is successfully trained, the optimized mapping corresponding to each input data information can be obtained in real time. To examine the efficacy of the proposed framework, we apply the method to the diffeomorphic image registration problem. Experimental results outperform other state-of-the-art registration algorithms in both efficiency and accuracy, which demonstrate the effectiveness of our proposed framework to solve the mapping problem.
Regarding Pauli's matrices as proper Higgs fields one can deduce an effective(!) approximation for gravity in flat space. In this work we extend this approximation up to the second order. Reaching complete agreement in the special case of gravitational waves. Unification in view, we introduce isospinorial degrees of freedom. In this way the mass spectrum and chiral asymmetry can be generated with the help of an additional scalar Higgs field. The Higgs modes corresponding to gravity are discussed.
We present a measurement of the anisotropic void-galaxy cross-correlation function in the CMASS galaxy sample of the BOSS DR12 data release. We perform a joint fit to the data for redshift space distortions (RSD) due to galaxy peculiar velocities and anisotropies due to the Alcock-Paczynski (AP) effect, for the first time using a velocity field reconstruction technique to remove the complicating effects of RSD in the void centre positions themselves. Fits to the void-galaxy function give a 1% measurement of the AP parameter combination $D_A(z)H(z)/c = 0.4367\pm 0.0045$ at redshift $z=0.57$, where $D_A$ is the angular diameter distance and $H$ the Hubble parameter, exceeding the precision obtainable from baryon acoustic oscillations (BAO) by a factor of ~3.5 and free of systematic errors. From voids alone we also obtain a 10% measure of the growth rate, $f\sigma_8(z=0.57)=0.501\pm0.051$. The parameter degeneracies are orthogonal to those obtained from galaxy clustering. Combining void information with that from BAO and galaxy RSD in the same CMASS sample, we measure $D_A(0.57)/r_s=9.383\pm 0.077$ (at 0.8% precision), $H(0.57)r_s=(14.05\pm 0.14)\;10^3$ kms$^{-1}$Mpc$^{-1}$ (1%) and $f\sigma_8=0.453\pm0.022$ (4.9%), consistent with cosmic microwave background (CMB) measurements from Planck. These represent a factor \sim2 improvement in precision over previous results through the inclusion of void information. Fitting a flat cosmological constant $\Lambda$CDM model to these results in combination with Planck CMB data, we find up to an 11% reduction in uncertainties on $H_0$ and $\Omega_m$ compared to use of the corresponding BOSS consensus values. Constraints on extended models with non-flat geometry and a dark energy of state that differs from $w=-1$ show an even greater improvement.
In recent times, there have been increasing accusations on artificial intelligence systems and algorithms of computer vision of possessing implicit biases. Even though these conversations are more prevalent now and systems are improving by performing extensive testing and broadening their horizon, biases still do exist. One such class of systems where bias is said to exist is facial recognition systems, where bias has been observed on the basis of gender, ethnicity, skin tone and other facial attributes. This is even more disturbing, given the fact that these systems are used in practically every sector of the industries today. From as critical as criminal identification to as simple as getting your attendance registered, these systems have gained a huge market, especially in recent years. That in itself is a good enough reason for developers of these systems to ensure that the bias is kept to a bare minimum or ideally non-existent, to avoid major issues like favoring a particular gender, race, or class of people or rather making a class of people susceptible to false accusations due to inability of these systems to correctly recognize those people.
We identify the quantum numbers of baryon exotics in the Quark Model, the Skyrme Model and QCD, and show that they agree for arbitrary colors and flavors. We define exoticness, E, which can be used to classify the states. The exotic baryons include the recently discovered qqqq qbar pentaquarks (E=1), as well as exotic baryons with additional q qbar pairs (E >=1). The mass formula for non-exotic and exotic baryons is given as an expansion in 1/N, and allows one to relate the moment of inertia of the Skyrme soliton to the mass of a constituent quark.
Time series of photospheric magnetic parameters of solar active regions (ARs) are used to answer whether scaling properties of fluctuations embedded in such time series help to distinguish between flare-quiet and flaring ARs. We examine a total of 118 flare-quiet and 118 flaring AR patches (called HARPs), which were observed from 2010 to 2016 by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). Specifically, the scaling exponent of fluctuations is derived applying the Detrended Fluctuation Analysis (DFA) method to a dataset of 8-day time series of 18 photospheric magnetic parameters at 12-min cadence for all HARPs under investigation. We first find a statistically significant difference in the distribution of the scaling exponent between the flare-quiet and flaring HARPs, in particular for some space-averaged, signed parameters associated with magnetic field line twist, electric current density, and current helicity. The flaring HARPs tend to show higher values of the scaling exponent compared to those of the flare-quiet ones, even though there is considerable overlap between their distributions. In addition, for both the flare-quiet and flaring HARPs the DFA analysis indicates that (1) time series of most of various magnetic parameters under consideration are non-stationary, and (2) time series of the total unsigned magnetic flux and the mean photospheric magnetic free energy density in general present a non-stationary, persistent property, while the total unsigned flux near magnetic polarity inversion lines and parameters related to current density show a non-stationary, anti-persistent trend in their time series.
Non-perturbative effects are studied for Type I strings on the Z_3 orbifold with Chan-Paton symmetry broken by Wilson lines. Generalizing previous analyses that have focussed on (bi)fundamentals, it is argued that (anti)symmetric representations of the resulting gauge group play a decisive role in generating an ADS-like superpotential in this and related cases. Non perturbative corrections in the closed string moduli are only allowed if properly dressed with open string fields charged under the anomalous U(1) of the orbifold. A general discussion of instanton effects in SYM and string theories is given. Non-perturbative superpotentials induced by both $ED5$'s and ED1's are analyzed. The superpotential generated by closed string fluxes, viz. Scherk-Schwarz shifts (torsion), R-R 3-form flux as well as non-geometric fluxes is derived. Some preliminary comments on the compatibility of the two kinds of superpotentials and the issue of moduli stabilization are presented.
Dynamical Mean-Field Theory (DMFT) has opened new perspectives for the investigation of strongly correlated electron systems and greatly improved our understanding of correlation effects in models and materials. In contrast to Hartree-Fock-type approximations the mean field of DMFT is dynamical, whereby local quantum fluctuations are fully taken into account. DMFT becomes exact in the limit of high spatial dimensions or coordination number. Using DMFT the dynamics of correlated electron systems can be investigated non-perturbatively at all interaction strengths, electron densities and temperatures. By merging density functional theory with DMFT a powerful method for the calculation of the properties of correlated electron materials has become available, which is applicable to bulk systems and heterostructures, including topological states of matter. The inclusion of non-local correlations into DMFT makes it possible to explore unconventional superconductivity and the critical behavior at thermal or quantum phase transitions. By generalizing DMFT to non-equilibrium states also the real-time dynamics of correlated systems can be investigated. In this brief review the foundations and current status of DMFT are discussed along with characteristic physical insights obtained with this approach.
We study the relative dust attenuation-inclination relation in 78,721 nearby galaxies using the axis ratio dependence of optical-NIR colour, as measured by the Sloan Digital Sky Survey (SDSS), the Two Micron All Sky Survey (2MASS), and the Wide-field Infrared Survey Explorer (WISE). In order to avoid to the greatest extent possible attenuation-driven biases, we carefully select galaxies using dust attenuation-independent near- and mid-IR luminosities and colours. Relative u-band attenuation between face-on and edge-on disc galaxies along the star forming main sequence varies from ~0.55 mag up to ~1.55 mag. The strength of the relative attenuation varies strongly with both specific star formation rate and galaxy luminosity (or stellar mass). The dependence of relative attenuation on luminosity is not monotonic, but rather peaks at $M_{3.4\mu m} \approx -21.5$, corresponding to $M_* \approx 3\times 10^{10}M_{Sun}$. This behavior stands seemingly in contrast to some older studies; we show that older works failed to reliably probe to higher luminosities, and were insensitive to the decrease in attenuation with increasing luminosity for the brightest star-forming discs. Back-of-the-envelope scaling relations predict the strong variation of dust optical depth with specific star formation rate and stellar mass. More in-depth comparisons using the scaling relations to model the relative attenuation require the inclusion of star-dust geometry to reproduce the details of these variations (especially at high luminosities), highlighting the importance of these geometrical effects.
We define and study a new class of 4d N=1 superconformal quiver gauge theories associated with a planar bipartite network. While UV description is not unique due to Seiberg duality, we can classify the IR fixed points of the theory by a permutation, or equivalently a cell of the totally non-negative Grassmannian. The story is similar to a bipartite network on the torus classified by a Newton polygon. We then generalize the network to a general bordered Riemann surface and define IR SCFT from the geometric data of a Riemann surface. We also comment on IR R-charges and superconformal indices of our theories.
We introduce extended chiral transformation, which depends both on pseudoscalar and diquark fields as parameters and determine its group structure. Assuming soft symmetry breaking in diquark sector, bosonisation of a quasi-Goldstone $ud$-diquark is performed. In the chiral limit the $ud$-diquark mass is defined by the gluon condensate, $m_{ud}\approx 300 MeV$. The diquark charge radius is $\langle r^2_{ud}\rangle^{1/2}\approx 0.5 fm$.
A poset has the non-messing-up property if it has two covering sets of disjoint saturated chains so that for any labeling of the poset, sorting the labels along one set of chains and then sorting the labels along the other set yields a linear extension of the poset. The linear extension yielded by thus twice sorting a labeled non-messing-up poset may be independent of which sort was performed first. Here we characterize such sort-invariant labelings for convex subposets of a cylinder. They are completely determined by avoidance of a particular subpattern: a diamond of four elements whose smallest two labels appear at opposite points.
We review and extend the computation of scattering amplitudes of tachyons in the $c=1$ matrix model using a manifestly finite prescription for the collective field hamiltonian. We give further arguments for the exactness of the cubic hamiltonian by demonstrating the equality of the loop corrections in the collective field theory with those calculated in the fermionic picture.
We provide analytical $O(\alpha_s)$ results for the three polarized decay structure functions $H_{++},\,H_{00}$ and $H_{--}$ that describe the decay of a polarized $W$ boson into massive quark--antiquark pairs. As an application we consider the decay $t\to b+W^+$ involving the helicity fractions $\rho_{mm}$ of the $W^+$ boson followed by the polarized decay $\hbox{$W^+(\uparrow)$}\to q_1\bar{q}_2$ described by the polarized decay structure functions $H_{mm}$. We thereby determine the $O(\alpha_s)$ polar angle decay distribution of the cascade decay process $t\to b+W^+(\to q_1\bar{q}_2)$. As a second example we analyze quark mass and off-shell effects in the cascade decays $H\to W^{-}+W^{\ast +}(\to q_1\bar{q}_2)$ and $H\to Z+Z^{\ast}(\to q\bar{q})$. For the decays $H\to W^{-}+W^{\ast +}(\to c\bar b)$ and $H\to Z+Z^{\ast}(\to b\bar{b})$ we find substantial deviations from the mass-zero approximation in particular in the vicinity of the threshold region.