ShantanuT01/DACTYL-Pretraining huggingface dataset:
In the MSSM with complex parameters, loop corrections to the decay of a stop into a bottom quark and a chargino can lead to a CP violating decay rate asymmetry. We calculate this asymmetry at full one-loop level and perform a detailed numerical study, analyzing the dependence on the parameters and complex phases involved. If the stop can decay into a gluino, the self-energy and the vertex correction dominate due to the strong coupling. It is shown that the vertex contribution is always suppressed. We therefore give a simple approximate formula for the asymmetry. We account for the constraints on the parameters coming from several experimental limits. Asymmetries up to 25 percent are obtained. We also comment on the feasibility of measuring this asymmetry at the LHC.
GR and other theories have been obtained from 3-space rather than spacetime principles. I explore consequences of this as regards the Problem of Time.
Observations of red (G-K)-giant stars with the CoRoT satellite provide unprecedented information on the stochastically excited oscillations in these stars. The long time series of nearly uninterrupted high-cadence and high-precision photometry revealed the presence of non-radial modes with long lifetimes, which opens the possibility to perform asteroseismology on these stars. Also, the large number of red giants, for which solar-like oscillations are now observed, allows for a more statistical investigation of the characteristics of solar-like oscillations in red giants.
We prove that the quantum stress tensor for a massless scalar field in two dimensional non-selfsimilar Tolman Bondi dust collapse and Vaidya radiation collapse models diverges on the Cauchy horizon, if the latter exists. The two dimensional model is obtained by suppressing angular co-ordinates in the corresponding four dimensional spherical model.
A recent theorem of [GGSM1] showed that adjoint orbits of semisimple Lie algebras have the structure of symplectic Lefschetz fibrations. We investigate the behaviour of their fibrewise compactifications. Expressing adjoint orbits and fibres as affine varieties in their Lie algebra, we compactify them to projective varieties via homogenisation of the defining ideals. We find that their Hodge diamonds vary wildly according to the choice of homogenisation, and that extensions of the potential to the compactification must acquire degenerate singularities.
Using Georgia State University's CHARA Array interferometer, we measured angular diameters for 25 giant stars, six of which host exoplanets. The combination of these measurements and Hipparcos parallaxes produce physical linear radii for the sample. Except for two outliers, our values match angular diameters and physical radii estimated using photometric methods to within the associated errors with the advantage that our uncertainties are significantly lower. We also calculated the effective temperatures for the stars using the newly-measured diameters. Our values do not match those derived from spectroscopic observations as well, perhaps due to the inherent properties of the methods used or because of a missing source of extinction in the stellar models that would affect the spectroscopic temperatures.
In the present paper we propose a doubly orbitally degenerate narrow-band model with correlated hopping. The peculiarity of the model is taking into account the matrix element of electron-electron interaction which describes intersite hoppings of electrons. In particular, this leads to the concentration dependence of the effective hopping integral. The cases of the strong and weak Hund's coupling are considered. By means of a generalized mean-field approximation the single-particle Green function and quasiparticle energy spectrum are calculated. Metal-insulator transition is studied in the model at different integer values of the electron concentration. With the help of the obtained energy spectrum we find energy gap width and criteria of metal-insulator transition.
The topic of this conference is ``The Chaotic Universe''. One of the main achievements of last century has been to relate chaos in fluids to their thermodynamics. It is our purpose to make connection between chaos in gravitation and standard thermodynamics. Though there have been many previous steps and attempts, so far no convincing conclusion has been reached.   After explaining how the approach works for glasses, we shall discuss the thermodynamics of two specific systems: black holes and globular star clusters. In both cases we point out that the dynamics satisfies the first and second law of thermodynamics, though negative specific heats occur.
In recent papers, we have argued that kinetically constrained coarse grained models can be applied to understand dynamic properties of glass forming materials, and we have used this approach in various applications that appear to validate this view. In one such paper [J.P. Garrahan and D. Chandler, Proc. Nat. Acad. Sci. USA 100, 9710 (2003)], among other things we argued that this approach also explains why the heat capacity discontinuity at the glass transition is generally larger for fragile materials than for strong materials. In the preceding article, Biroli, Bouchaud and Tarjus (BB&T) [cond-mat/0412024] have objected to our explanation on this point, arguing that the class of models we apply is inconsistent with both the absolute size and temperature dependence of the experimental specific heat. Their argument, however, neglects parameters associated with the coarse graining. Accounting for these parameters, we show here that our treatment of dynamics is not inconsistent with heat capacity discontinuities.
Let $\F$ be a family of $r$ integral forms of degree $k\geq 2$ and $\LL=(l_1,\ldots,l_m)$ be a family of pairwise linearly independent linear forms in $n$ variables $\x=(x_1,...,x_n)$. We study the number of solutions $\x\in[1,N]^n$ to the diophantine system $\F(\x)=\vv$ under the restriction that $l_i(\x)$ has a bounded number of prime factors for each $1\leq i\leq m$. We show that the system $\F$ have the expected number of such "almost prime" solutions under similar conditions as was established for existence of integer solutions by Birch.
We study the formation of BTZ black holes by the collision of point particles. It is shown that the Gott time machine, originally constructed for the case of vanishing cosmological constant, provides a precise mechanism for black hole formation. As a result, one obtains an exact analytic understanding of the Choptuik scaling.
The second Hi-C flight (Hi-C2.1) provided unprecedentedly-high spatial and temporal resolution ($\sim$250km, 4.4s) coronal EUV images of Fe IX/X emission at 172 \AA, of AR 12712 on 29-May-2018, during 18:56:21-19:01:56 UT. Three morphologically-different types (I: dot-like, II: loop-like, III: surge/jet-like) of fine-scale sudden-brightening events (tiny microflares) are seen within and at the ends of an arch filament system in the core of the AR. Although type Is (not reported before) resemble IRIS-bombs (in size, and brightness wrt surroundings), our dot-like events are apparently much hotter, and shorter in span (70s). We complement the 5-minute-duration Hi-C2.1 data with SDO/HMI magnetograms, SDO/AIA EUV images, and IRIS UV spectra and slit-jaw images to examine, at the sites of these events, brightenings and flows in the transition-region and corona and evolution of magnetic flux in the photosphere. Most, if not all, of the events are seated at sites of opposite-polarity magnetic flux convergence (sometimes driven by adjacent flux emergence), implying likely flux cancellation at the microflare's polarity inversion line. In the IRIS spectra and images, we find confirming evidence of field-aligned outflow from brightenings at the ends of loops of the arch filament system. In types I and II the explosion is confined, while in type III the explosion is ejective and drives jet-like outflow. The light-curves from Hi-C, AIA and IRIS peak nearly simultaneously for many of these events and none of the events display a systematic cooling sequence as seen in typical coronal flares, suggesting that these tiny brightening-events have chromospheric/transition-region origin.
We develop the parquet-diagram summation method for neutron matter interacting via potentials that include spin, tensor, and spin-orbit components. For that purpose, we derive an exact expression for the sum of all ring-diagrams in terms effective local particle-hole interactions involving the above four operators. The parquet equations are closed by deriving the spin-orbit contribution to that particle-hole interaction. We show that many-body correlations screen the bare spin-orbit potential considerably, and the corrections of that screened spin-orbit potential to the other three interaction channels are quite small. We apply our method to the calculation of the response of neutron matter to density and both longitudinal and transverse spin-dependent external fields.
We systematically analyze backgrounds that are holographic duals to non-relativistic CFTs, by constructing them as cosets of the Schrodinger group and variants thereof. These cosets G/H are generically non-reductive and we discuss in generality how a metric on such spaces can be determined from a non-degenerate H-invariant symmetric two-form. Applying this to the d=2 Schrodinger algebra, we reproduce the five-dimensional backgrounds proposed as duals of fermions at unitarity, and under reasonable physical assumptions, we demonstrate uniqueness of this background. The proposed gravity dual of the Lifshitz fixed-point, for which Galileian symmetry is absent, also fits into this organizational scheme and uniqueness of this background can also be shown.
Being able to accurately estimate stellar parameters based on spectral observations is important not only for understanding the stars themselves but it is also vital for the determination of exoplanet parameters. M dwarfs are discussed as targets for planet detection as these stars are less massive, less luminous and have smaller radii making it possible to detect smaller and lighter planets. Therefore M-dwarfs could prove to be a valuable source for examining the lower mass end of planet distribution, but in order to do that, one must first take care to understand the characteristics of the host stars well enough. Up to date, there are several families of stellar model atmospheres. We focus on the ATLAS9, MARCS and Drift-Phoenix families in the M-dwarf parameter space. We examine the differences in the (Tgas, pgas) structures, synthetic photometric fluxes and related colour indices.We find discrepancies in the hotter regions of the stellar atmosphere between the ATLAS and MARCS models. The MARCS and Drift-Phoenix models appear to agree to a better extend with variances of less than 300K. We have compiled the broad-band synthetic photometric fluxes of all models for the Johnson UBVRI and 2MASS JHKs. The fluxes of MARCS differ from both ATLAS and Drift-Phoenix models in the optical range.
Being motivated in terms of mathematical concepts from the theory of electrical networks, Klein & Ivanciuc introduced and studied a new graph-theoretic cyclicity index--the global cyclicity index (Graph cyclicity, excess conductance, and resistance deficit, J. Math. Chem. 30 (2001) 271--287). In this paper, by utilizing techniques from graph theory, electrical network theory and real analysis, we obtain some further results on this new cyclicity measure, including the strictly monotone increasing property, some lower and upper bounds, and some Nordhuas-Gaddum-type results. In particular, we establish a relationship between the global cyclicity index $C(G)$ and the cyclomatic number $\mu(G)$ of a connected graph $G$ with $n$ vertices and $m$ edges: $$\frac{m}{n-1}\mu(G)\leq C(G)\leq \frac{n}{2}\mu(G).$$
Effective Hamiltonian methods are utilized to model the two-qubit cross-resonance gate for both the ideal two-qubit case and when higher levels are included. Analytic expressions are obtained in the qubit case and the higher-level model is solved both perturbatively and numerically with the solutions agreeing well in the weak drive limit. The methods are applied to parameters from recent experiments and accounting for classical cross-talk effects results in good agreement between theory and experimental results.
Quantum field theory on d+1-dimensional anti-deSitter space-time admits a re-interpretation as a quantum field theory with conformal symmetry on d-dimensional Minkowski space-time. This conjecture originally emerged from string theory considerations. Here, it is proven in a general framework by an explicit identification between the local observables of the two corresponding theories.
In this paper we consider a telegraph equation with time-dependent coefficients, governing the persistent random walk of a particle moving on the line with a time-varying velocity $c(t)$ and changing direction at instants distributed according to a non-stationary Poisson distribution with rate $\lambda(t)$. We show that, under suitable assumptions, we are able to find the exact form of the probability distribution. We also consider the space-fractional counterpart of this model, finding the characteristic function of the related process. A conclusive discussion is devoted to the potential applications to run-and-tumble models.
Heavy axion-like particles have been introduced in several scenarios beyond the Standard Model and their production in some astrophysical systems should be possible. In this work, we re-examine the possibility that these type of particles can be generated in the accretion disks of gamma-ray bursts (GRB), the most powerful events in the universe. If the produced axions decay into photons or $e^+e-$ pairs at the correct distances, a fireball is generated. We calculate the structure transient accretion disks in GRBs (density, temperature and thickness profiles) taking into account the effect of heavy axion emission as well as the rest of the relevant standard cooling processes. This allows us to obtain the values of the coupling constant g_{aN} in order for the axions not to become trapped, and we can also compute the emitted heavy axion luminosity from the entire disk. We find that for the couplings within the ranges found, then the mechanism for powering GRBs based on heavy axion production and decay becomes an alternative to the standard picture based upon magnetohydrodynamic processes and neutrino-antineutrino annihilation. Otherwise, if heavy axions are produced in the disk but their decay to takes place further away, the mechanism fails. Still, the decay products (gamma rays or electrons and positrons) should leave observable signatures which are not observed for different ranges of values of the coupling constants, depending on the mass of the heavy axion
High throughput and low latency inference of deep neural networks are critical for the deployment of deep learning applications. This paper presents the efficient inference techniques of IntelCaffe, the first Intel optimized deep learning framework that supports efficient 8-bit low precision inference and model optimization techniques of convolutional neural networks on Intel Xeon Scalable Processors. The 8-bit optimized model is automatically generated with a calibration process from FP32 model without the need of fine-tuning or retraining. We show that the inference throughput and latency with ResNet-50, Inception-v3 and SSD are improved by 1.38X-2.9X and 1.35X-3X respectively with neglectable accuracy loss from IntelCaffe FP32 baseline and by 56X-75X and 26X-37X from BVLC Caffe. All these techniques have been open-sourced on IntelCaffe GitHub1, and the artifact is provided to reproduce the result on Amazon AWS Cloud.
We study moduli spaces of (possibly non-nodal) curves (C,p_1,\ldots,p_n) of arithmetic genus g with n smooth marked points, equipped with nonzero tangent vectors, such that ${\mathcal O}_C(p_1+\ldots+p_n)$ is ample and $H^1({\mathcal O}_C(a_1p_1+\ldots+a_np_n))=0$ for given weights ${\bf a}=(a_1,\ldots,a_n)$ such that $a_i\ge 0$ and $\sum a_i=g$. We show that each such moduli space $\widetilde{{\mathcal U}}^{ns}_{g,n}({\bf a})$ is an affine scheme of finite type, and the Krichever map identifies it with the quotient of an explicit locally closed subscheme of the Sato Grassmannian by the free action of the group of changes of formal parameters. We study the GIT quotients of $\widetilde{{\mathcal U}}^{ns}_{g,n}({\bf a})$ by the natural torus action and show that some of the corresponding stack quotients give modular compactifications of ${\mathcal M}_{g,n}$ with projective coarse moduli spaces. More generally, using similar techniques, we construct moduli spaces of curves with chains of divisors supported at marked points, with prescribed number of sections, which in the case n=1 corresponds to specifying the Weierstrass gap sequence at the marked point.
We derive an expression for the expansion of outgoing null geodesics in spherical dust collapse and compute the limiting value of the expansion in the approach to singularity formation. An analogous expression is derived for the spherical collapse of a general form of matter. We argue on the basis of these results that the covered as well as the naked singularity solutions arising in spherical dust collapse are stable under small changes in the equation of state.
In this paper, conditions for transience, recurrence, ergodicity and strong, subexponential (polynomial) and exponential ergodicity of a class of Feller processes are derived. The conditions are given in terms of the coefficients of the corresponding infinitesimal generator. As a consequence, mixing properties of these processes are also discussed.
I present an algorithm based on sector decomposition and Mellin-Barnes techniques to power expand Feynman integrals. The coefficients of this expansion are given in terms of finite integrals that can be calculated numerically. I show in an example the benefit of this method for getting the full analytic power expansion from differential equations by providing the correct ansatz for the solution. For method of regions the presented algorithm provides a numerical check, which is independent from any power counting argument.
Spin Hall oscillators (SHO) are promising candidates for the generation, detection and amplification of high frequency signals, that are tunable through a wide range of operating frequencies. They offer to be read out electrically, magnetically and optically in combination with a simple bilayer design. Here, we experimentally study the spatial dependence and spectral properties of auto-oscillations in SHO devices based on Pt(7 nm)/\ Ni$_{\mathrm{80}}$Fe$_{\mathrm{20}}$(5 nm) tapered nanowires. Using Brillouin light scattering microscopy, we observe two individual self-localized spin-wave bullets that oscillate at two distinct frequencies (5.2 GHz and 5.45 GHz) and are localized at different positions separated by about 750 nm within the SHO. This state of a tapered SHO has been predicted by a Ginzburg-Landau auto-oscillator model, but not yet been directly confirmed experimentally. We demonstrate that the observed bullets can be individually synchronized to external microwave signals, leading to a frequency entrainment, linewidth reduction and increase in oscillation amplitude for the bullet that is selected by the microwave frequency. At the same time, the amplitude of other parasitic modes decreases, which promotes the single-mode operation of the SHO. Finally, the synchronization of the spin-wave bullets is studied as a function of the microwave power. We believe that our findings promote the realization of extended spin Hall oscillators accomodating several distinct spin-wave bullets, that jointly cover an extended range of tunability.
We present a nonperturbative field theoretic method based on the Liouville-Neumann (LN) equation. The LN approach provides a unified formulation of nonperturbative quantum fields and also nonequilibrium quantum fields, which makes use of mean-field type equations and whose results at the lowest level are identically the same as those of the Gaussian effective potential approach and the mean-field approach. The great advantageous point of this formulation is its readiness of applicability to time-dependent quantum systems and to finite temperature field theory, and its possibility to go beyond the Gaussian approximation.
High-temperature indium flux growth was applied to prepare single crystals of GdRh$_2$Si$_2$ by a modified Bridgman method leading to mm-sized single crystals with a platelet habitus. Specific heat and susceptibility data of GdRh$_2$Si$_2$ exhibit a pronounced anomaly at $T_N = 107\rm \,K$, where the AFM ordering sets in. Magnetic measurements on the single crystals were performed down to $T = 2$\,K in external fields from B = 0 - 9\,T applied along the $[100]$-, $[110]$- and $[001]$-direction of the tetragonal lattice. The effective magnetic moment determined from a Curie-Weiss fit agrees well with values from literature, and is larger than the theoretically predicted value. Electrical transport data recorded for current flow parallel and perpendicular to the $[001]$-direction show a large anisotropy below $T_N$. The residual resistivity ratio $\rm RRR=\rho_{300K}/\rho_{0}\sim 23$ demonstrates that we succeeded in preparing high-quality crystals using high-temperature indium flux-growth.
We discuss the possibility of a 2D ordered structure formed upon deposition of Si on metal surfaces. We investigate the atomic and electronic structure of the Si-$(\sqrt{19}\times\sqrt{19})R23.4^{\circ}$/Pt(111) surface reconstruction by means of a set of experimental surface-science techniques supported by theoretical calculations. The theory achieves a very good agreement with the experimental results and corroborate beyond any doubt that this phase is a surface alloy consisting of Si$_3$Pt tetramers that resembles a twisted Kagome lattice. These findings render unlikely any formation of silicene or germanene on Pt(111) and other transition metal surfaces.
Macrospicules (MS) are localised small-scale jet-like phenomena in the solar atmosphere, which have the potential to transport considerable amount of momentum and energy from the lower solar atmospheric regions to the Transition Region and the low corona. A detailed statistical analysis of their temporal behaviour and spatial properties is carried out in this work. By means of state-of-the-art spatial and temporal resolution observations, yielded by the Atmospheric Imaging Assembly (AIA) of Solar Dynamics Observatory (SDO), we constructed a database covering a 5.5-year long period, containing 301 macrospicules that occurred between June 2010 and December 2015 detected at 30.4 nm wavelength. Here, we report the long-term variation of the height, length, average speed and width of MS in Coronal Holes and Quiet Sun areas both in the northern and southern hemisphere of the Sun. This new database helps to refine our knowledge about the physical properties of MS. Cross-correlation of these properties show a relatively strong correlation, but not always a dominant one. However, a more detailed analysis indicates a wave-like signature in the behaviour of MS properties in time. The period of these long-term oscillatory behaviours are just under two years. Also, in terms of solar north/south hemispheres, a strong asymmetry was found in the spatial distribution of MS properties, which may be accounted for the solar dynamo. This latter feature may then indicate a strong and rather intrinsic link between global internal and local atmospheric phenomena in the Sun.
We investigate the geoeffective events happened from 8 to 20 Sept 2011, analysing the most plausible solar sources of these events, where coronal mass ejections and coronal holes play a fundamental role. The physical properties of the coronal holes, such as area and magnetic field, are studied through the Solar Dynamics Observatory instruments: AIA 193 {\AA} images and HMI longitudinal magnetograms. The active regions which are the origin of the coronal mass ejections are analysed in AIA and SoHO-LASCO data.