ShantanuT01/DACTYL-Pretraining huggingface dataset:
Magnetic and other unconventional electronic orders are discussed for heavy electrons. In addition to the ordinary Kondo lattice, we consider non-Kramers systems taking the two-channel Kondo lattice, and another lattice that consists of a singlet-triplet f2 configuration. The latter gives a scalar order with staggered sublattices of crystalline-electric-field (CEF) and Kondo singlets, which accounts for the observed order in PrFe4P12. In the two-channel Kondo lattice, an odd-frequency pairing is realized that becomes degenerate at half-filling with a composite order involving both localized and conduction electrons. The degeneracy is interpreted in terms of a hidden SO(5) symmetry. For the ordinary Kondo lattice with exchange interaction J, we take insulating ground states as reference. The metallic states are approached by infinitesimal doping of carriers either from the Kondo insulator or from the antiferromagnetic insulator. By adding intersite exchange we find that location of the band extremum of the heavy band depends on the value of J. The change of J gives topological change of the Fermi surface, which corresponds to a generalized version of the Lifshitz transition, and occurs separately from the quantum critical point of the antiferromagnetic order.
We present the results of VLA, ATCA, and Swift XRT observations of the 2015 outburst of the transient neutron star X-ray binary (NSXB), EXO 1745$-$248, located in the globular cluster Terzan 5. Combining (near-) simultaneous radio and X-ray measurements we measure a correlation between the radio and X-ray luminosities of $L_R\propto L_X^\beta$ with $\beta=1.68^{+0.10}_{-0.09}$, linking the accretion flow (probed by X-ray luminosity) and the compact jet (probed by radio luminosity). While such a relationship has been studied in multiple black hole X-ray binaries (BHXBs), this work marks only the third NSXB with such a measurement. Constraints on this relationship in NSXBs are strongly needed, as comparing this correlation between different classes of XB systems is key in understanding the properties that affect the jet production process in accreting objects. Our best fit disc-jet coupling index for EXO 1745$-$248 is consistent with the measured correlation in NSXB 4U 1728$-$34 ($\beta=1.5\pm 0.2$) but inconsistent with the correlation we fit using the most recent measurements from the literature of NSXB Aql X-1 ($\beta=0.76^{+0.14}_{-0.15}$). While a similar disc-jet coupling index appears to hold across multiple BHXBs in the hard accretion state, this does not appear to be the case with the three NSXBs measured so far. Additionally, the normalization of the EXO 1745$-$248 correlation is lower than the other two NSXBs, making it one of the most radio faint XBs ever detected in the hard state. We also report the detection of a type-I X-ray burst during this outburst, where the decay timescale is consistent with hydrogen burning.
The problems causality and causality violation in topologically nontrivial space-time models are considered. To this end the mixed boundary problem for traversable wormhole models is formulated and the influence of the boundary conditions on the causal properties of space-time is analyzed
Early-time observations of Type Ia supernovae (SNe Ia) are essential to constrain their progenitor properties. In this paper, we present high-quality light curves of 127 SNe Ia discovered by the Zwicky Transient Facility (ZTF) in 2018. We describe our method to perform forced point spread function (PSF) photometry, which can be applied to other types of extragalactic transients. With a planned cadence of six observations per night ($3g+3r$), all of the 127 SNe Ia are detected in both $g$ and $r$ band more than 10\,d (in the rest frame) prior to the epoch of $g$-band maximum light. The redshifts of these objects range from $z=0.0181$ to 0.165; the median redshift is 0.074. Among the 127 SNe, 50 are detected at least 14\,d prior to maximum light (in the rest frame), with a subset of 9 objects being detected more than 17\,d before $g$-band peak. This is the largest sample of young SNe Ia collected to date; it can be used to study the shape and color evolution of the rising light curves in unprecedented detail. We discuss six peculiar events in this sample, including one 02cx-like event ZTF18abclfee (SN\,2018crl), one Ia-CSM SN ZTF18aaykjei (SN\,2018cxk), and four objects with possible super-Chandrasekhar mass progenitors: ZTF18abhpgje (SN\,2018eul), ZTF18abdpvnd (SN\,2018dvf), ZTF18aawpcel (SN\,2018cir) and ZTF18abddmrf (SN\,2018dsx).
We present early time, high resolution spectroscopy of three GRB afterglows: GRB050730, GRB050922C and GRB060418. These data give us precious information on the kinematics, ionization and metallicity of the interstellar matter of GRB host galaxies up to a redshift z = 4, and of intervening absorbers along the line of sight. The absorption spectra show that elements are present both with high and low ionization states, and even forbidden, fine structure levels are commonly observed. These features allow us to evaluate the physical parameters of the absorbing gas. In details, the density of the gas regions lie in the range n = 10 - 10^6 cm-3, and the temperatures are of the order of T = 10^3 - 10^4 K. The metallicity of the GRB host galaxies is computed using the hydrogen absorption features. We find undersolar abundances for our GRBs, namely, Z = 0.001 - 0.01. However, depletion has not been considered. It can be taken into account using as metallicity indicators Zn and Cr, which tend to remain in the gas phase. We find metallicities higher than the previous values and in agreement with other measurements for GRB host galaxies. Finally, the observed [C/Fe] ratio for GRB050730 (z = 3.967) agrees with values expected for a galaxy younger than a Gyr undergoing bursts of star-formation. In addition, the [C/Fe] ratio evaluated component by component can give informations on the relative distances of the components from the GRB explosion site, since Fe dust is more efficiently destroyed than graphite.
Measurements of line-of-sight dependent clustering via the galaxy power spectrum's multipole moments constitute a powerful tool for testing theoretical models in large-scale structure. Recent work shows that this measurement, including a moving line-of-sight, can be accelerated using Fast Fourier Transforms (FFTs) by decomposing the Legendre polynomials into products of Cartesian vectors. Here, we present a faster, optimal means of using FFTs for this measurement. We avoid redundancy present in the Cartesian decomposition by using a spherical harmonic decomposition of the Legendre polynomials. Consequently, our method is substantially faster: a given multipole of order $\ell$ requires only $2\ell+1$ FFTs rather than the $(\ell+1)(\ell+2)/2$ FFTs of the Cartesian approach. For the hexadecapole ($\ell = 4$), this translates to $40\%$ fewer FFTs, with increased savings for higher $\ell$. The reduction in wall-clock time enables the calculation of finely-binned wedges in $P(k,\mu)$, obtained by computing multipoles up to a large $\ell_{\rm max}$ and combining them. This transformation has a number of advantages. We demonstrate that by using non-uniform bins in $\mu$, we can isolate plane-of-sky (angular) systematics to a narrow bin at $\mu \simeq 0$ while eliminating the contamination from all other bins. We also show that the covariance matrix of clustering wedges binned uniformly in $\mu$ becomes ill-conditioned when combining multipoles up to large values of $\ell_{\rm max}$, but that the problem can be avoided with non-uniform binning. As an example, we present results using $\ell_{\rm max}=16$, for which our procedure requires a factor of 3.4 fewer FFTs than the Cartesian method, while removing the first $\mu$ bin leads only to a 7% increase in statistical error on $f \sigma_8$, as compared to a 54% increase with $\ell_{\rm max}=4$.
Recently, Zhang {\em et al.} [PRA, {\bf 75}, 062102 (2007)] extended Kieu's interesting work on the quantum Otto engine [PRL, {\bf 93}, 140403 (2004)] by considering as working substance a bipartite quantum system $AB$ composed of subsystems $A$ and $B$. In this paper, we express the net work done $W_{AB}$ by such an engine explicitly in terms of the macroscopic bath temperatures and information theoretic quantities associated with the microscopic quantum states of the working substance. This allows us to gain insights into the dependence of positive $W_{AB}$ on the quantum properties of the states. We illustrate with a two-qubit XY chain as the working substance. Inspired by the expression, we propose a plausible formula for the work derivable from the subsystems. We show that there is a critical entanglement beyond which it is impossible to draw positive work locally from the individual subsystems while $W_{AB}$ is positive. This could be another interesting manifestation of quantum nonlocality.
Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir waves to nonlinear processes of wave-wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over large frequency range, including the effects of electron transport, Langmuir wave-electron interaction, the evolution of Langmuir waves due to non-linear wave-wave interactions, Langmuir wave conversion into electromagnetic emission, and finally escape of the electromagnetic waves. For the first time we simulate escaping radio emission over a broad frequency range from 500~MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, {identification as fundamental or harmonic emission}, peak flux density, instantaneous frequency bandwidth, and timescales for rise and decay. Comparing with the observations, these large scale simulations enable us to identify the processes governing the key type III solar radio burst characteristics.
Failure cases of black-box deep learning, e.g. adversarial examples, might have severe consequences in healthcare. Yet such failures are mostly studied in the context of real-world images with calibrated attacks. To demystify the adversarial examples, rigorous studies need to be designed. Unfortunately, complexity of the medical images hinders such study design directly from the medical images. We hypothesize that adversarial examples might result from the incorrect mapping of image space to the low dimensional generation manifold by deep networks. To test the hypothesis, we simplify a complex medical problem namely pose estimation of surgical tools into its barest form. An analytical decision boundary and exhaustive search of the one-pixel attack across multiple image dimensions let us localize the regions of frequent successful one-pixel attacks at the image space.
Hydrogen-rich core collapse supernovae, known as "Type II" supernovae, are the most common type of stellar explosion realized in nature. They are defined by the presence of prominent hydrogen lines in their spectra. Type II supernovae are observed only in star-forming galaxies, and several events have been directly linked to massive star progenitors. Five main subclasses are identified: Type IIP (displaying a plateau in their light curve), Type IIL (displaying a light curve decline), Type IIn (displaying narrow emission lines), Type IIb (displaying increasingly strong He features with time) and 87A-likes (displaying long-rising light curves similar to that of SN 1987A). Type IIP supernovae have been robustly established as the explosions of red supergiants, while the progenitors of Type IIL's remain elusive. Type IIn's are likely linked to luminous blue variables, Type IIb progenitors may be interacting binary systems and the prototype of the 87A-like class was observed to be the explosion of a blue supergiant. The diversity in progenitor mass, metallicity, binarity and rotation is likely responsible for the diversity in observed explosion types, but the connection between progenitor parameters and supernova properties is not yet entirely understood theoretically nor fully mapped observationally. New observational methods for constraining this connection are currently being implemented, including the analyses of large samples of events, making use of very early data (obtained hours to days from explosion) and statistical studies of host-galaxy properties.
We consider a family of pseudo differential operators $\{\Delta+ a^\alpha \Delta^{\alpha/2}; a\in [0, 1]\}$ on $\R^d$ that evolves continuously from $\Delta$ to $\Delta + \Delta^{\alpha/2}$, where $d\geq 1$ and $\alpha \in (0, 2)$. It gives rise to a family of L\'evy processes \{$X^a, a\in [0, 1]\}$, where $X^a$ is the sum of a Brownian motion and an independent symmetric $\alpha$-stable process with weight $a$. Using a recently obtained uniform boundary Harnack principle with explicit decay rate, we establish sharp bounds for the Green function of the process $X^a$ killed upon exiting a bounded $C^{1,1}$ open set $D\subset\R^d$. As a consequence, we identify the Martin boundary of $D$ with respect to $X^a$ with its Euclidean boundary. Finally, sharp Green function estimates are derived for certain L\'evy processes which can be obtained as perturbations of $X^a$.
The energy distributions of four 2+1 dimensional black hole solutions were obtained by using the Einstein and M{\o}ller energy-momentum complexes. while $r \to \infty$, the energy distributions of these four solutions become divergence.
This article classifies Knutsen K3 surfaces all of whose hyperplane sections are irreducible and reduced. As an application, this gives infinite families of K3 surfaces of Picard number two whose general hyperplane sections are Brill-Noether general curves.
We determine the scattered near-field and directly emitted power of a heated spherical nanoparticle above a sample within the framework of fluctuational electrodynamics using the dipole approximation. Our results deviate from previously obtained results. Additionally, we show that in a configuration where the nanoparticle is heated with respect to its environment, the scattered power of the near field of the sample is strictly zero. Only when the sample is heated or the temperature of the surroundings of the sample is lowered is there a contribution from the scattered power. Our results indicate that for the interpretation of near-field imaging setups as the thermal infrared near-field spectroscope not only the scattering of the near field but also the direct emission of the tip plays a role.
Arbitrated quantum signatures (AQS), for signing quantum message, have been proposed. It was claimed that the AQS schemes could guarantee unconditional security. However, in this paper, we show that all the presented AQS protocols are insecure if quantum one-time pad encryption is used where the signer Alice can always successfully acquire Bob's secret key and disavow any of her signatures. The detailed attack strategies and security analysis are described. Furthermore, the original version of the protocols is revised and accordingly the security of the AQS protocols are improved. And meanwhile we present a method to against Alice's disavowal proposed by Gao et al. (arXiv:1106.4398v1).
Surface electronic properties of undoped hydrogen terminated diamond covered with adsorbates or in electrolyte solutions are summarized. The formation of a conductive layer at the surface of diamond is discussed based on Hall effect, conductivity, contact potential difference (CPM), scanning electron microscopy (SEM), and cyclic voltammetry data applied on homoepitaxially grown CVD diamond films with atomically smooth hydrogen terminated surfaces. Due to electron transfer from valence band states into empty states of the electrolyte (transfer doping), a highly conductive surface layer is generated. Holes propagate in the layer with mobilities up to 350 cm2/Vs. The sheet hole density is in the range 10^11 to 5x10^12 cm^-2, and dependents on pH of the electrolyte. Numerical solutions of the Schrodinger and Poisson equations reveal a 2D density of state (DOS) distribution. This has been utilized to manufacture ion-sensitive field effect transistors (ISFET). The drain source conductivity is pH dependent, with about 66 mV/pH. Application of potentials larger than the oxidation threshold of +0.7 V (pH 13) to +1.6 V (pH 1) gives rise to strong leakage currents and to partial surface oxidation.
X-ray resonant magnetic scattering studies of rare earth magnetic ordering were performed on perovskite manganites RMnO3 (R = Dy, Gd) in an applied magnetic field. The data reveal that the field-induced three-fold polarization enhancement for H || a (H approx. 20 kOe) observed in DyMnO3 below 6.5 K is due to a re-emergence of the Mn-induced Dy spin order with propagation vector k(Dy) = k(Mn) = 0.385 b*, which accompanies the suppression of the independent Dy magnetic ordering, k(Dy) = 1/2 b*. For GdMnO3, the Mn-induced ordering of Gd spins is used to track the Mn-ordering propagation vector. The data confirm the incommensurate ordering reported previously, with k(Mn) varying from 0.245 to 0.16 b* on cooling from T_N(Mn) down to a transition temperature T'. New superstructure reflections which appear below T' suggest a propagation vector k(Mn) = 1/4 b* in zero magnetic field, which may coexist with the previously reported A-type ordering of Mn. The Gd spins order with the same propagation vector below 7 K. Within the ordered state of Gd at T = 1.8 K we find a phase boundary for an applied magnetic field H || b, H = 10 kOe, which coincides with the previously reported transition between the ground state paraelectric and the ferroelectric phase of GdMnO3. Our results suggest that the magnetic ordering of Gd in magnetic field may stabilize a cycloidal ordering of Mn that, in turn, produces ferroelectricity.
We examine correlations of transverse particle displacements and their relationship to the shear modulus of a glass and the viscosity of a fluid. To this end we use computer simulations to calculate a correlation function of the displacements, $S_4(q;t)$, which is similar to functions used to study heterogeneous dynamics in glass-forming fluids. We show that in the glass the shear modulus can be obtained from the long-time, small-q limit of $S_4(q;t)$. By using scaling arguments, we argue that a four-point correlation length $\xi_4(t)$ grows linearly in time in a glass and grows as $\sqrt{t}$ at long times in a fluid, and we verify these results by analyzing $S_4(q;t)$ obtained from simulations. For a viscoelastic fluid, the simulation results suggest that the crossover to the long-time $\sqrt{t}$ growth of $\xi_4(t)$ occurs at a characteristic decay time of the shear stress autocorrelation function. Using this observation, we show that the amplitude of the long-time $\sqrt{t}$ growth is proportional to $\sqrt{\eta}$ where $\eta$ is the viscosity of the fluid.
We evaluate the mutual information between the input and the output of a two layer network in the case of a noisy and non-linear analogue channel. In the case where the non-linearity is small with respect to the variability in the noise, we derive an exact expression for the contribution to the mutual information given by the non-linear term in first order of perturbation theory. Finally we show how the calculation can be simplified by means of a diagrammatic expansion. Our results suggest that the use of perturbation theories applied to neural systems might give an insight on the contribution of non-linearities to the information transmission and in general to the neuronal dynamics.
Jets and outflows from Young Stellar Objects (YSOs) are important signposts of currently ongoing star formation. In order to study these objects we are conducting an unbiased survey along the Galactic Plane in the 1-0S(1) emission line of molecular hydrogen at 2.122mu using the UK Infrared Telescope. In this paper we are focusing on a 33 square degree sized region in Serpens and Aquila (18deg < l < 30deg; -1.5deg < b < +1.5deg).   We trace 131 jets and outflows from YSOs, which results in a 15 fold increase in the total number of known Molecular Hydrogen Outflows. Compared to this, the total integrated 1-0S(1) flux of all objects just about doubles, since the known objects occupy the bright end of the flux distribution. Our completeness limit is 3*10^-18Wm^-2 with 70% of the objects having fluxes of less than 10^-17Wm^-2.   Generally, the flows are associated with Giant Molecular Cloud complexes and have a scale height of 25-30pc with respect to the Galactic Plane. We are able to assign potential source candidates to about half the objects. Typically, the flows are clustered in groups of 3-5 objects, within a radius of 5pc. These groups are separated on average by about half a degree, and 2/3rd of the entire survey area is devoid of outflows. We find a large range of apparent outflow lengths from 4arcsec to 130arcsec. If we assume a distance of 3kpc, only 10% of all outflows are of parsec scale. There is a 2.6sigma over abundance of flow position angles roughly perpendicular to the Galactic Plane.
A781 belongs to a complex system characterized by extended X-ray emissions that may form part of line of clusters of galaxies along a filament. The aim of this work is to investigate the possible presence of extended, diffuse synchrotron radio emission connected to the intra-cluster medium of A781. We studied the radio continuum emission and the spectral index properties in proximity of the A781 by analyzing archival Very Large Array observations at 1400 and 325 MHz. The main cluster of the system is permeated by diffuse low-surface brightness radio emission which is classified, being located close to the center, as a radio halo. The diffuse emission presents the typical extension and radio power of the other halos known in the literature. Interestingly, the radio halo appears to be linked to a peripheral patch previously found in the literature. The spectrum of this peripheral emission shows a radial steepening which may confirm that this source is indeed a cluster relic.
Using the low energy effective Hamiltonian with the generalized factorization, we calculate the new physics contributions to $B \to \pi^+ \pi^-, K \pi$ and $K \etap$ in the Topcolor-assisted-Technicolor(TC2) model, and compare the results with the available data. By using $F_0^{{\rm B\pi}}(0)=0.20\pm 0.04$ preferred by the CLEO data of $B \to \pi^+ \pi^-$ decay, we find that the new physics enhancements to $B \to K \etap$ decays are significant in size, $\sim 50%$ with respect to the standard model predictions, insensitive to the variations of input parameters and hence provide a simple and plausible new physics interpretation for the observed unexpectedly large $B\to K \etap$ decay rates.
We prove a new generalization of Davenport's Fourier expansion of the infinite series involving the fractional part function over arithmetic functions. A new Mellin transform related to the Riemann zeta function is also established.