ShantanuT01/DACTYL-Pretraining huggingface dataset:
A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals.
In this white paper for the Snowmass process, we discuss the prospects of probing new physics explanations of the persistent rare $B$ decay anomalies with a muon collider. If the anomalies are indirect signs of heavy new physics, non-standard rates for $\mu^+ \mu^- \to b s$ production should be observed with high significance at a muon collider with center of mass energy of $\sqrt{s} = 10$ TeV. The forward-backward asymmetry of the $b$-jet provides diagnostics of the chirality structure of the new physics couplings. In the absence of a signal, $\mu^+ \mu^- \to b s$ can indirectly probe new physics scales as large as $86$ TeV. Beam polarization would have an important impact on the new physics sensitivity.
The paper deals with the problem of describing fundamental particles. The Einstein-Rosen approach was revisited to explain que charge-mass ratio quantization. Such a result is obtained once a quantization prescription is applied to the expression of gravitational energy defined in the realm of teleparallel gravity.
Recent observations of coherent radiation from the Crab pulsar (Bij et al 2021) suggest the emission is driven by an ultra - relativistic ($\gamma \sim 10^4$), cold plasma flow. A relativistically expanding plasma shell can compress the ambient magnetic field, like a moving mirror, and thus produce coherent radiation whose wavelength is shorter than that of the ambient medium by $\gamma^2$. This mechanism has been studied in the past by Colgate and Noerdelinger (1971), in the context of radio loud supernova explosions. In this work we propose that a similar mechanism drives the coherent emission in fast radio bursts. The high Lorenz factors dramatically lower the implied energy and magnetic field requirements, allowing the spin down energy of regular (or even recycled), fast spinning pulsars, rather than slow spinning magnetars, to explain FRBs. We show that this model can explain the frequency and the time evolution of observed FRBs, as well as their duration, energetics and absence of panchromatic counterparts. We also predict that the peak frequency of sub pulses decline with observation time as $\omega_{\rm obs} \propto t_{\rm obs}^{-1/2}$. Unfortunately, with current capabilities it is not possible to constrain the shape of the curve $\omega_{\rm obs} \left(t_{\rm obs} \right)$. Finally, we find that a variation of this model can explain weaker radio transients, such as the one observed from a galactic magnetar. In this variant, the shock wave produces low frequency photons which are then Compton scattered to the GHz range.
In this paper, we study a new type of stochastic functional differential equations which is called hybrid pantograph stochastic functional differential equations. We investigate several moment properties and sample properties of the solutions to the equations by using the method of multiple Lyapunov functions, such as the moment exponential stability, almost sure exponential stability and almost sure polynomial stability, etc.
We use a prescription to gauge the su(2) Skyrme model with a U(1) field, characterised by a conserved Baryonic current. This model reverts to the usual Skyrme model in the limit of the gauge coupling constant vanishing. We show that there exist axially symmetric static solutions with zero magnetic charge, which can be electrically either charged or uncharged. The energies of the (uncharged) gauged Skyrmions are less than the energy of the (usual) ungauged Skyrmion. For physical values of the parameters the impact of the U(1) field is very small, so that it can be treated as a perturbation to the (ungauged) spherically symmetric Hedgehog. This allows the perturbative calculation of the magnetic moment.
We discuss the interpretation of present and possible future experimental constraints on B_s to mu^+ mu^- decay in the context of the constrained minimal extension of the Standard Model (CMSSM) with universal scalar masses. We emphasize the importance of including theoretical and other experimental uncertainties in calculating the likelihood function, which can affect significantly the inferred 95% confidence-level limit on the CMSSM parameters. The principal uncertainties are the B_s meson decay constant, m_t and m_b. The latter induce uncertainties in the mass of the charged Higgs boson that dominates the B_s to mu^+ mu^- decay amplitude at large tan beta, reducing the CMSSM region excluded by present and possible future limits from the Fermilab Tevatron collider and the LHC.
Expanding visual categorization into a novel domain without the need of extra annotation has been a long-term interest for multimedia intelligence. Previously, this challenge has been approached by unsupervised domain adaptation (UDA). Given labeled data from a source domain and unlabeled data from a target domain, UDA seeks for a deep representation that is both discriminative and domain-invariant. While UDA focuses on the target domain, we argue that the performance on both source and target domains matters, as in practice which domain a test example comes from is unknown. In this paper we extend UDA by proposing a new task called unsupervised domain expansion (UDE), which aims to adapt a deep model for the target domain with its unlabeled data, meanwhile maintaining the model's performance on the source domain. We propose Knowledge Distillation Domain Expansion (KDDE) as a general method for the UDE task. Its domain-adaptation module can be instantiated with any existing model. We develop a knowledge distillation based learning mechanism, enabling KDDE to optimize a single objective wherein the source and target domains are equally treated. Extensive experiments on two major benchmarks, i.e., Office-Home and DomainNet, show that KDDE compares favorably against four competitive baselines, i.e., DDC, DANN, DAAN, and CDAN, for both UDA and UDE tasks. Our study also reveals that the current UDA models improve their performance on the target domain at the cost of noticeable performance loss on the source domain.
Many biological processes are supported by special molecules, called motor proteins or molecular motors, that transport cellular cargoes along linear protein filaments and can reversibly associate to their tracks. Stimulated by these observations, we developed a theoretical model for collective dynamics of biological molecular motors that accounts for local association/dissociation events. In our approach, the particles interacting only via exclusion move along a lattice in the preferred direction, while the reversible associations are allowed at the specific site far away from the boundaries. Considering the association/dissociation site as a local defect, the inhomogeneous system is approximated as two coupled homogeneous sub-lattices. This allows us to obtain a full description of stationary dynamics in the system. It is found that the number and nature of steady-state phases strongly depend on the values of association and dissociation transition rates. Microscopic arguments to explain these observations, as well as biological implications, are also discussed. Theoretical predictions agree well with extensive Monte Carlo computer simulations.
We prove that the charge-scalar field (also known as the massless Maxwell-Klein-Gordon) equations are globally stable on (3+1) dimensional Minkowski space for small initial data in certain gauge covariant weighted Sobolev spaces. These spaces can be chosen as to be almost scale invariant with respect to the homogeneity of the equations. This result is valid for initial data with non-zero charge that is also non-stationary at space-like infinity. The method of proof is a tensor-geometric approach which is based on a certain family of weighted bilinear L2 space-time estimates.
Let $p\equiv 2,5\mod 9$ be an odd prime. In this paper, we prove that at least one of $3p$ and $3p^2$ is a cube sum by constructing certain nontrivial Heegner points. We also establish the explicit Gross-Zagier formulae for these Heegner points and give variants of the Birch and Swinnerton-Dyer conjecture of the related elliptic curves.
The aim of this work is to study the energy transport by means of MHD waves propagating in quiet Sun magnetic topology from layers below the surface to the corona. Upward propagating waves find obstacles, such as the equipartition layer with plasma b=1 and the transition region, and get converted, reflected and refracted. Understanding the mechanisms by which MHD waves can reach the corona can give us information about the solar atmosphere and the magnetic structures. We carry out two-dimensional numerical simulations of wave propagation in a magnetic field structure that consists of two vertical flux tubes separated by an arcade shaped magnetic field. This configuration contains a null point in the corona, that significantly modifies the behaviour of the waves. We describe in detail the wave propagation through the atmosphere under different driving conditions. We also present the spatial distribution of the mean acoustic and magnetic energy fluxes and the spatial distribution of the dominant frequencies in the whole domain. We conclude that the energy reaches the corona preferably along vertical magnetic fields, inside the flux tubes, and it has an acoustic nature. Most of the magnetic energy keeps concentrated below the transition region due to the refraction of the magnetic waves and the continuous conversion of acoustic-like waves into fast magnetic waves in the equipartition layer located in the photosphere. However, part of the magnetic energy reaches the low corona when propagating in the region where the arcades are located, but waves are sent back downwards to the lower atmosphere at the null point surroundings. This phenomenon, together with the reflection and refraction of waves in the TR and the lower turning point, act as a re-feeding of the atmosphere. In the frequency distribution, we find that high frequency waves can reach the corona outside the vertical flux tubes.
Intrinsic volumes, which generalize both Euler characteristic and Lebesgue volume, are important properties of $d$-dimensional sets. A random cubical complex is a union of unit cubes, each with vertices on a regular cubic lattice, constructed according to some probability model. We analyze and give exact polynomial formulae, dependent on a probability, for the expected value and variance of the intrinsic volumes of several models of random cubical complexes. We then prove a central limit theorem for these intrinsic volumes. For our primary model, we also prove an interleaving theorem for the zeros of the expected-value polynomials. The intrinsic volumes of cubical complexes are useful for understanding the shape of random $d$-dimensional sets and for characterizing noise in applications.
Using a chiral unitary model in which the negative parity nucleon resonance $N^\ast \equiv N^\ast(1535)$ is generated dynamically by means of the Bethe Salpeter equation with coupled meson baryon channels in the $S = 0$ sector, we have obtained the $\pi^0 N^\ast N^\ast$ and $\eta N^\ast N^\ast$ couplings. The $\pi^0 N^\ast N^\ast$ coupling has smaller strength and the same sign as the $\pi^0 N N$ coupling. This rules out the mirror assignment of chiral symmetry where the ground state nucleon $N$ and the negative parity resonance $N^\ast$ are envisaged as chiral partners in the baryon sector.
We present Fermi-LAT and multi-frequency, multi-epoch VLBA data for the TeV blazar Mrk421. We collected the data during a long and intensive multi-frequency campaign in 2011. We study the gamma-ray light curve, the photon index evolution and their connection to the radio data on sub-parsec scales, including total intensity, polarized flux density, polarization angle, spectral index, and rotation measure both in the core and the jet region. The VLBA data were obtained at 15 and 24 GHz for 12 epochs and at 43 GHz for 23 epochs, thus providing the best temporal and spatial coverage in the radio band ever achieved for a TeV blazar. We provide significant constraints on the jet Doppler factor, the presence of proper motion, the magnetic field configuration, and an intriguing connection between variability in the radio data and the gamma-ray light curve: the total intensity and polarized core emission reach a peak simultaneously to the main gamma-ray peak, followed by a rotation of the polarization angle at low frequency. Opacity-related, long wavelength polarization swings are also detected later in the year, possibly related to secondary peaks in the gamma-ray light curve, setting constraints on the physics of the gamma-ray zone.
The second-order gravitational self-force on a small body is an important problem for gravitational-wave astronomy of extreme mass-ratio inspirals. We give a first-principles derivation of a prescription for computing the first and second perturbed metric and motion of a small body moving through a vacuum background spacetime. The procedure involves solving for a "regular field" with a specified (sufficiently smooth) "effective source", and may be applied in any gauge that produces a sufficiently smooth regular field.
Hard X-ray generation for Au nanoparticle dispersion was systematically investigated for different particle diameters ranging from 10 to 100 nm with a narrow size distribution of +/- 2%. Scaling law of X-ray generation is close to a 6-photon process before the onset of saturation for excitation by 45 fs laser pulses with central wavelength of 800 nm. This is consistent with bulk plasmon excitation at wavelength ~ 138 nm. The longitudinal E-field component due to nanoparticle focusing is responsible for the excitation of the longitudinal bulk plasmon. The proposed analysis also explains X-ray emission from water breakdown via an electron solvation mechanism at ~6.2 eV. The most efficient emission of X-rays was observed for 40 +/- 10 nm diameter nanoparticles which also had the strongest UV extinction. X-ray emission was the most efficient when induced by pre-chirped 370 +/- 20 fs laser pulses and exhibited the highest intensity at a negative chirp.
No transient electromagnetic emission has yet been found in association to fast radio bursts (FRBs), the only possible exception (3sigma confidence) being the putative gamma-ray signal detected in Swift/BAT data in the energy band 15-150 keV at the time and position of FRB131104. Systematic searches for hard X/gamma-ray counterparts to other FRBs ended up with just lower limits on the radio/gamma-ray fluence ratios. In 2001, at the time of the earliest discovered FRBs, the BeppoSAX Gamma-Ray Burst Monitor (GRBM) was one of the most sensitive open sky gamma-ray monitors in the 40-700~keV energy band. During its lifetime, one of the FRBs with the highest radio fluence ever recorded, FRB010724 (800 +- 400 Jy ms), also known as the Lorimer burst, was promptly visible to the GRBM. Upon an accurate modeling of the GRBM background, eased by its equatorial orbit, we searched for a possible gamma-ray signal in the first 400 s following the FRB, similar to that claimed for FRB131104 and found no significant emission down to a 5-sigma limit in the range (0.24-4.7)x10^-6 erg cm^-2 (corresponding to 1 and 400 s integration time, respectively), in the energy band 40-700 keV. This corresponds to eta = F_radio/F_gamma>10^{8-9} Jy ms erg^-1 cm^2, i.e. the deepest limit on the ratio between radio and gamma-ray fluence, which rules out a gamma-ray counterpart similar to that of FRB131104. We discuss the implications on the possible mechanisms and progenitors that have been proposed in the literature, also taking into account its relatively low dispersion measure (375 +- 3 pc cm^-3) and an inferred redshift limit of z<0.4.
We present a semi-analytical approach to the determination of the dynamic properties of randomly branched polymers under the Rouse approximation. The principle procedure is based on examining a spectrum of eigenvalues which represents the average dynamic behavior of various structures. The calculated spectra show that the eigenvalue distribution is random even within a single structure which in turn produces a continuous spectrum of values for the entire class. The auto-correlation functions for the radius of gyration squared were calculated based on these spectra, which confirms that the dynamics is non-exponential as earlier reported. A universal stretched exponent is also found in this study.
Since the commissioning of the array in Spring 2007, the VERITAS array (sensitive in the 0.1-50 TeV energy range) has acquired over 300 hours of observations investigating the TeV emission from X-ray binary star systems, in particular focusing on the known TeV binary targets LS I +61 303 and HESS J0632+057. Both TeV binaries have been monitored by VERITAS for several years and the resulting dataset is continuing to yield important results in the characterization of these poorly understood systems. We present these results, as well as the contemporaneous observations of these sources taken with Fermi-LAT and Swift-XRT. In the case of LS I +61 303, simultaneous observations taken with VERITAS and Fermi-LAT reveal a break in emission in the 10-200 GeV range. For HESS J0632 057, the extended VERITAS observations have allowed for the first identification of a binary system through TeV gamma-ray observations.
We give a bijective proof of a conjecture of Regev and Vershik on the equality of two multisets of hook numbers of certain skew-Young diagrams. The bijection proves a result that is stronger and more symmetric than the original conjecture, by means of a construction involving Dyck paths, a particular type of lattice path.
We have performed a detailed study of conductance anisotropy and magnetoresistance (MR) of La2-xSrxCuO4 (LSCO) thin films (0.10 < x < 0.25). These two observables are promising for the detection of stripes. Subtle features of the conductance anisotropy are revealed by measuring the transverse resistance Rxy in zero magnetic field. It is demonstrated that the sign of Rxy depends on the orientation of the LSCO Hall bar with respect to the terrace structure of the substrate. Unit-cell-high substrate step edges must therefore be a dominant nucleation source for antiphase boundaries during film growth. We show that the measurement of Rxy is sensitive enough to detect the cubic-tetragonal phase transition of the SrTiO3(100) (STO) substrate at 105 K. The MR of LSCO thin films shows for 0.10 < x < 0.25 a non-monotonic temperature dependence, resulting from the onset of a linear term in the MR above 90 K. We show that the linear MR scales with the absolute Hall resistivity, with the constant of proportionality independent of temperature. Such scaling suggests that the linear MR originates from current distortions induced by structural or electronic inhomogeneities. The possible role of stripes for both the MR and the conductance anisotropy is discussed throughout the paper.
We report on high-resolution photoluminescence (PL) and photocurrent (PC) spectroscopies of a single self-assembled InAs/GaAs quantum dot (QD) embedded in an n-i-Schottky device with an applied magnetic field in Faraday and Voigt geometries. The single-QD PC spectrum of neutral exciton (X$^0$) is obtained by sweeping the bias-dependent X$^0$ transition energy to achieve resonance with a fixed narrow-bandwidth laser through quantum-confined Stark effect. With a magnetic field applied in Faraday geometry, the diamagnetic effect and the Zeeman splitting of X$^0$ are observed both in PL and PC spectra. When the magnetic field is applied in Voigt geometry, the mixture of bright and dark states results in an observation of dark exciton states, which are confirmed by the polarization-resolved PL and PC spectra.
The aim of this paper is to show that there exists a deterministic algorithm that can be applied to compute the factors of a polynomial of degree 2, defined over a finite field, given certain conditions.
We consider a discrete-time version of the popular optimal dividend pay-out problem in risk theory. The novel aspect of our approach is that we allow for a risk averse insurer, i.e., instead of maximising the expected discounted dividends until ruin we maximise the expected utility of discounted dividends until ruin. This task has been proposed as an open problem in H. Gerber and E. Shiu (2004). The model in a continuous-time Brownian motion setting with the exponential utility function has been analysed in P. Grandits, F. Hubalek, W. Schachermayer and M. Zigo (2007). Nevertheless, a complete solution has not been provided. In this work, instead we solve the problem in discrete-time setup for the exponential and the power utility functions and give the structure of optimal history-dependent dividend policies. We make use of certain ideas studied earlier in N. B\"auerle and U. Rieder (2013), where Markov decision processes with general utility functions were treated. Our analysis, however, include new aspects, since the reward functions in this case are not bounded.
Aims: This paper has two main objectives: (1) To determine the intrinsic properties of 16 faint and mostly unstudied open clusters in the poorly known sector of the Galaxy at 270$^\circ-$300$^\circ$, to probe the Milky Way structure in future investigations. (2) To address previously reported systematics in Gaia DR2 parallaxes by comparing the cluster distances derived from photometry with those derived from parallaxes. Methods: Deep UBVI photometry of 16 open clusters was carried out. Observations were reduced and analyzed in an automaticway using the ASteCA package to get individual distances, reddening, masses, ages and metallicities. Photometric distances were compared to those obtained from a Bayesian analysis of Gaia DR2 parallaxes. Results: Ten out of the 16 clusters are true or highly probable open clusters. Two of them are quite young and follow the trace of the Carina Arm and the already detected warp. The rest of the clusters are placed in the interarm zone between the Perseus and Carina Arms as expected for older objects. We found that the cluster van den Berg-Hagen 85 is 7.5$\times$10$^9$ yrs old becoming then one of the oldest open cluster detected in our Galaxy so far. The relationship of these ten clusters with the Galaxy structure in the solar neighborhood is discussed. The comparison of distances from photometry and parallaxes data, in turn, reveals a variable level of disagreement. Conclusions: Various zero point corrections for Gaia DR2 parallax data recently reported were considered for a comparison between photometric and parallax based distances. The results tend to improve with some of these corrections. Photometric distance analysis suggest an average correction of $\sim$+0.026 mas (to be added to the parallaxes). The correction may have a more intricate distance dependency, but addressing that level of detail will require a larger cluster sample.