ShantanuT01/DACTYL-Pretraining huggingface dataset:
We consider the stationary solutions of N=4 supergravity coupled to n vector multiplets that define linear superpositions of non-interacting extremal black holes. The most general solutions of this type are derived from the graded decompositions of so(8,2+n) associated to its nilpotent orbits. We illustrate the formalism by giving explicitly asymptotically Minkowski non-BPS solutions of the most exotic class depending on 6+n harmonic functions.
The gravitational lens 0957+561 was monitored with the Very Large Array from 1979 to 1997. The 6 cm light curve data from 1995-1997 and the 4 cm data from 1990-1997 are reported here. At 4 cm, the intrinsic source variations occur earlier and are twice as large as the corresponding variations at 6 cm. The VLBI core and jet components have different magnification factors, leading to different flux ratios for the varying and non-varying portions of the VLA light curves. Using both the PRHQ and Dispersion statistical techniques, we determined the time delay, core flux ratio, and excess non-varying B image flux density. The fits were performed for the 4 cm and 6 cm light curves, both individually and jointly, and we used Gaussian Monte Carlo data to estimate 68% statistical confidence levels. The delay estimates from each individual wavelength were inconsistent given the formal uncertainties, suggesting that there are unmodeled systematic errors in the analysis. We roughly estimate the systematic uncertainty in the joint result from the difference between the 6 cm and 4 cm results, giving 409+-30 days for the PRHQ statistic and 397+-20 days for the Dispersion statistic. These results are consistent with the current optical time delay of 417+-3 days, reconciling the long-standing difference between the optical and radio light curves and between different statistical analyses. The unmodeled systematic effects may also corrupt light curves for other lenses, and we caution that multiple events at multiple wavelengths may be necessary to determine an accurate delay in any lens system. Now that consensus has been reached regarding the time delay in the 0957+561 system, the most pressing issue remaining for determining H_0 is a full understanding of the mass distribution in the lens.
After briefly reviewing the gauge symmetry in Moyal spacetimes, we analyse aspects of symmetry breaking within a quantisation program preserving the twisted Poincar\'e symmetry. We develop the LSZ approach for Moyal spacetimes and derive a mapping for scattering amplitudes on these spacetimes from the corresponding ones on the commutative spacetime. This map applies in the presence of spontaneous breakdown of symmetries as well. We also derive Goldstone's theorem on Moyal spacetime. The formalism developed here can be directly applied to the twisted standard model.
For a projective K3 surface X we introduce the dense triangulated subcategory S^* of the bounded derived category D^b(Coh(X)) of coherent sheaves on X that is generated by spherical objects. For a K3 surface X over \bar Q it is shown that S^* admits a bounded t-structure if and only if the Bloch-Beilinson conjecture holds for X, i.e. CH^2(X)=Z.
We perform a detailed analysis of renormalization at one-loop order in the $\lambda\phi^4$ theory with Robin boundary condition (characterized by a constant $c$) on a single plate at $z=0$. For arbitrary $c\geq0$ the renormalized theory is finite after the inclusion of the usual mass and coupling constant counterterms, and two independent surface counterterms. A surface counterterm renormalizes the parameter $c$. The other one may involve either an additional wave-function renormalization for fields at the surface, or an extra quadratic surface counterterm. We show that both choices lead to consistent subtraction schemes at one-loop order, and that moreover it is possible to work out a consistent scheme with both counterterms included. In this case, however, they can not be independent quantities. We study a simple one-parameter family of solutions where they are assumed to be proportional to each other, with a constant $\vartheta$. Moreover, we show that the renormalized Green functions at one-loop order does not depend on $\vartheta$. This result is interpreted as indicating a possible new renormalization ambiguity related to the choice of $\vartheta$.
The problem of completing a partially specified n by n Latin square is solved by an alternative proof, based on filling the rows (or diagonals) from 1 to n, using an extended form of Hall's marriage theorem.
We investigated SrFeO$_{3-x}$ thin films on a SrTiO$_3$ (001) substrate prepared via pulsed laser epitaxy using an optical spectroscopy technique. The oxygen vacancy level ($x$) was controlled by post-annealing processes at different oxygen partial pressures. We achieved a brownmillerite(BM) structure at $x =$ 0.5 and observed the evolution of the crystal structure from BM into perovskite(PV) as the oxygen concentration increased. We observed the evolution of infrared-active phonons with respect to the oxygen concentration, which was closely related to the structural evolution observed via X-ray diffraction. We identified the phonons using the shell-model calculation. Furthermore, we studied temperature-dependent behaviors of the phonon modes of three representative samples: PV, and two BMs (BM$_{\mathrm{oop}}$ and BM$_{\mathrm{ip}}$) with different orientations of the oxygen vacancy channel. In the BM$_{\mathrm{oop}}$ sample, we observed a phonon mode, which exhibited an unusual red-shift with decreasing temperature; this behavior may have been due to the apical oxygen instability in the FeO$_6$ octahedron. Our results provide important information regarding the ionic conduction mechanism in SrFeO$_{3-x}$ material systems.
Shanks's sequence of quadratic fields $\Q(\sqrt{S_{n}})$ where $S_{n}=(2^n+1)^2 + 2^{n+2}$ instances a class of quadratic fields for which the class number is large and, therefore, the continued fraction period is relatively short. Indeed, that period length increases linearly with $n$, that is: in arithmetic progression. The fields have regulator $O(n^2)$. In the late nineties, these matters intrigued Irving Kaplansky, and led him to compute period length of the square root of sequences $a^2x^{2n}+bx^{n}+c$ for integers $a$, $b$, $c$, and $x$. In brief, Kap found unsurprisingly that, generically, triples $(a,b,c)$ are `leapers': they yield sequences with period length increasing at exponential rate. But there are triples yielding sequences with constant period length, Kap's `sleepers'. Finally, there are triples, as exemplified by the Shanks's sequence, for which the period lengths increase in arithmetic progression. Felicitously, Kaplansky called these `creepers'. It seems that the sleepers and creepers are precisely those for which one is able to detail the explicit continued fraction expansion for all $n$. Inter alia, this thesis noticeably extends the known classes of creepers and finds that not all are `kreepers' (of the shape identified by Kaplansky) and therefore not of the shape of examples studied by earlier authors looking for families of quadratic number fields with explicitly computable unit and of relatively large regulator. The work of this thesis includes the discovery of old and new families of hyperelliptic curves of increasing genus $g$ and torsion divisor of order $O(g^2)$. It follows that the apparent trichotomy leaper/sleeper/creeper coincides with the folk belief that the just-mentioned torsion is maximum possible.
Infrared spectroscopy of the H-alpha emission lines of a sub-sample of 19 high-redshift (0.8 < z < 2.3) Molonglo quasars, selected at 408 MHz, is presented. These emission lines are fitted with composite models of broad and narrow emission, which include combinations of classical broad-line regions of fast-moving gas clouds lying outside the quasar nucleus, and/or a theoretical model of emission from an optically-thick, flattened, rotating accretion disk. All bar one of the nineteen sources are found to have emission consistent with the presence of an optically-emitting accretion disk, with the exception appearing to display complex emission including at least three broad components. Ten of the quasars have strong Bayesian evidence for broad-line emission arising from an accretion disk together with a standard broad-line region, selected in preference to a model with two simple broad lines. Thus the best explanation for the complexity required to fit the broad H-alpha lines in this sample is optical emission from an accretion disk in addition to a region of fast-moving clouds. We derive estimates of the angle between the rotation axis of the accretion disk and the line of sight. A weak correlation is found between the accretion disk angle and the logarithm of the low-frequency radio luminosity. This is direct, albeit tenuous, evidence for the receding torus model. Velocity shifts of the broad H-alpha components are analysed and the results found to be consistent with a two-component model comprising one single-peaked broad line emitted at the same redshift as the narrow lines, and emission from an accretion disk which appears to be preferentially redshifted with respect to the narrow lines for high-redshift sources and blueshifted relative to the narrow lines for low-redshift sources.
Parameterized relativistic dynamics (PRD) is a manifestly covariant quantum theory with invariant evolution parameter. The theory has been applied to neutrino flavor oscillations between two mass states. It is generalized here to transitions between three mass states and applied to electron neutrino oscillations.
The infinite two-sided loop-erased random walk (LERW) is a measure on infinite self-avoiding walks that can be viewed as giving the law of the `middle part' of an infinite LERW loop going through 0 and infinity. In this note we derive expressions for transition probabilities for this model in dimensions two and up. In the plane, the formula can be further expressed in terms of a Laplacian with signed weights acting on certain discrete harmonic functions at the tips of the walk, and taking a determinant. The discrete harmonic functions are closely related to a discrete version of the complex square-root.
We discuss the effects of collisions on the expansion of a degenerate normal Fermi gas, following the sudden removal of the confining trap. Using a Boltzmann equation approach, we calculate the time dependence of the aspect ratio and the entropy increase of the expanding atomic cloud taking into account the collisional effects due to the deformation of the distribution function in momentum space. We find that in dilute gases the aspect ratio does not deviate significantly from the predictions of ballistic expansion. Conversely, if the trap is sufficiently elongated the thermal broadening of the density distribution due to the entropy increase can be sizeable, revealing that even at zero temperature collisions are effective in a Fermi gas.
We have searched for [OIII] 5007 emission in high resolution spectroscopic data from Flames/Giraffe VLT observations of 174 massive globular clusters (GCs) in NGC4472. No planetary nebulae (PNe) are observed in these clusters, constraining the number of PNe per bolometric luminosity, \alpha<0.8*10^{-7}PN/L_{\odot}. This is significantly lower than the rate predicted from stellar evolution, if all stars produce PNe. Comparing our results to populations of PNe in galaxies, we find most galaxies have a higher \alpha than these GCs (more PNe per bolometric luminosity - though some massive early-type galaxies do have similarly low \alpha). The low \alpha required in these GCs suggests that the number of PNe per bolometric luminosity does not increase strongly with decreasing mass or metallicity of the stellar population. We find no evidence for correlations between the presence of known GC PNe and either the presence of low mass X-ray binaries (LMXBs) or the stellar interaction rates in the GCs. This, and the low \alpha observed, suggests that the formation of PNe may not be enhanced in tight binary systems. These data do identify one [OIII] emission feature, this is the (previously published) broad [OIII] emission from the cluster RZ 2109. This emission is thought to originate from the LMXB in this cluster, which is accreting at super-Eddington rates. The absence of any similar [OIII] emission from the other clusters favors the hypothesis that this source is a black hole LMXB, rather than a neutron star LMXB with significant geometric beaming of its X-ray emission.
The positions of multiple images in galaxy lenses are related to the galaxy mass distribution. Smooth elliptical mass profiles were previously shown to be inadequate in reproducing the quad population. In this paper, we explore the deviations from such smooth elliptical mass distributions. Unlike most other work, we use a model-free approach based on the relative polar image angles of quads, and their position in 3D space with respect to the Fundamental Surface of Quads. The FSQ is defined by quads produced by elliptical lenses. We have generated thousands of quads from synthetic populations of lenses with substructure consistent with $\Lambda$CDM simulations, and found that such perturbations are not sufficient to match the observed distribution of quads relative to the FSQ. The result is unchanged even when subhalo masses are increased by a factor of ten, and the most optimistic lensing selection bias is applied. We then produce quads from galaxies created using two components, representing baryons and dark matter. The transition from the mass being dominated by baryons in inner radii to being dominated by dark matter in outer radii can carry with it asymmetries, which would affect relative image angles. We run preliminary experiments using lenses with two elliptical mass components with nonidentical axis ratios and position angles, perturbations from ellipticity in the form of nonzero Fourier coefficients $a_4$ and $a_6$, and artificially offset ellipse centers as a proxy for asymmetry at image radii. We show that combination of these effects is a promising way of accounting for quad population properties. We conclude that the quad population provides a unique and sensitive tool for constraining detailed mass distribution in the centers of galaxies.
We compute the soft and virtual NNLO QCD corrections to Higgs production through gluon-gluon fusion at hadron colliders. We present numerical results obtained at the LHC and at the Tevatron Run II.
We study the interplay between a XY anisotropy $\gamma$, exchange modulations and an external magnetic field along the z direction in the XYZ chain using bosonization and Lanczos diagonalization techniques. We find an Ising critical line in the space of couplings which occur due to competing relevant perturbations which are present. More general situations are also discussed.
We identify the space of symplectic deformations of maximal gauged supergravity theories. Coordinates of such space parametrize inequivalent supergravity models with the same gauge group. We apply our procedure to the SO(8) gauging, extending recent analyses. We also study other interesting cases, including Cremmer-Scherk-Schwarz models and gaugings of groups contained in SL(8,R) and in SU*(8).
It is not currently clear how important it will be to include conservative self-force (SF) corrections in the models for extreme-mass-ratio inspiral (EMRI) waveforms that will be used to detect such signals in LISA (Laser Interferometer Space Antenna) data. These proceedings will address this issue for circular-equatorial inspirals using an approximate EMRI model that includes conservative corrections at leading post-Newtonian order. We will present estimates of the magnitude of the parameter estimation errors that would result from omitting conservative corrections, and compare these to the errors that will arise from noise fluctuations in the detector. We will also use this model to explore the relative importance of the second-order radiative piece of the SF, which is not presently known.
We state and prove a function field analogue of Furusho for multiple zeta values.
We report strong THz-induced transparency in CVD-grown graphene where 92%-96% of the peak-field is transmitted compared to 74% at lower field strength. Time-resolved THz-pump/THz-probe studies reveal that the absorption recovers in 2-3 ps. The induced transparency is believed to arise from nonlinear pumping of carriers in graphene which suppresses the mobility and consequently the conductivity in a spectral region where the light-matter interaction is particularly strong.
The degree of influence that environment and mass have on the stellar populations of early-type galaxies is uncertain. In this paper we present the results of a spectroscopic analysis of the stellar populations of early-type galaxies aimed at addressing this question. The sample of galaxies is drawn from four clusters, with <z>=0.04, and their surrounding structure extending to ~10R_{vir}. We find that the distributions of the absorption-line strengths and the stellar population parameters age, metallicity and alpha-element abundance ratio do not differ significantly between the clusters and their outskirts, but the tight correlations found between these quantities and velocity dispersion within the clusters are weaker in their outskirts. All three stellar population parameters of cluster galaxies are positively correlated with velocity dispersion. Galaxies in clusters form a homogeneous class of objects that have similar distributions of line-strengths and stellar population parameters, and follow similar scaling relations regardless of cluster richness or morphology. We estimate the intrinsic scatter of the Gaussian distribution of metallicities to be 0.3 dex, while that of the alpha-element abundance ratio is 0.07 dex. The e-folding time of the exponential distribution of galaxy ages is estimated to be 900 Myr. The intrinsic scatters of the metallicity and alpha-element abundance ratio distributions can almost entirely be accounted for by the correlations with velocity dispersion and the intrinsic scatter about these relations. This implies that a galaxies mass plays the major role in determining its stellar population.
In this contribution we consider an advantageous building block with potential for various quantum applications: a device based on coupled spins capable of generating and sharing out an entangled pair of qubits. Our model device is a dimerised spin chain with three weakly coupled embedded sites (defects). Three different entangling protocols were proposed for this chain in [1] and [2], one producing a Cluster state and two generating a Bell state, depending on the initial state injection. Here we compare the robustness of such protocols as quantum entangling gates against different types of fabrication (static energy fluctuations) and operation (timing injection delays) errors.
I present new results on the extinction and on the YSO content of the Chamaeleon I cloud using the star count method that I have implemented and applied to DENIS and optical data. Application of this method to other nearby Large Molecular Clouds is in progress and is briefly outlined.
Yang-Baxter (YB) deformations of type IIB string theory have been well studied from the viewpoint of classical integrability. Most of the works, however, are focused upon the local structure of the deformed geometries and the global structure still remains unclear. In this work, we reveal a non-geometric aspect of YB-deformed backgrounds as $T$-fold by explicitly showing the associated $\mathrm{O}(D,D;\mathbb{Z})$ $T$-duality monodromy. In particular, the appearance of an extra vector field in the generalized supergravity equations (GSE) leads to the non-geometric $Q$-flux. In addition, we study a particular solution of GSE that is obtained by a non-Abelian $T$-duality but cannot be expressed as a homogeneous YB deformation, and show that it can also be regarded as a $T$-fold. This result indicates that solutions of GSE should be non-geometric quite in general beyond the YB deformation.
We report a magnetic state in GaV$_4$Se$_8$ which emerges exclusively in samples with mesoscale polar domains and not in polar mono-domain crystals. Its onset is accompanied with a sharp anomaly in the magnetic susceptibility and the magnetic torque, distinct from other anomalies observed also in polar mono-domain samples upon transitions between the cycloidal, the N\'eel-type skyrmion lattice and the ferromagnetic states. We ascribe this additional transition to the formation of magnetic textures localized at structural domain walls, where the magnetic interactions change stepwise and spin textures with different spiral planes, hosted by neighbouring domains, need to be matched. A clear anomaly in the magneto-current indicates that the domain-wall-confined magnetic states also have strong contributions to the magnetoelectric response. We expect polar domain walls to commonly host such confined magnetic edge states, especially in materials with long wavelength magnetic order.
We prove some cycle relations on moduli of K3 surfaces
In this work, doping-defect interactions relevant to self-compensation in p-type GaN were investigated using atom probe tomography. The 3D visualization of ion distribution revealed the formation of spherical Mg-rich clusters and the segregation of Mg dopant towards dislocations in MOCVD-grown GaN:Mg. Impurities related to self-compensation, such as oxygen and hydrogen, were identified and detected adjacent to Mg-rich dislocations. Crystal stoichiometry around the defect regions was investigated to understand how the defects can serve as traps and influence dopant diffusion. Non-stoichiometric regions of N:Ga were found adjacent to Mg-rich dislocations and overlapping with some Mg-rich clusters, indicating potential traps. Variations in N:Ga were not proportional to the Mg content, suggesting that the microfeatures (clusters and dislocations) interact differently with local chemistry. Techniques for defining the quality of an APT experiment through invalidation of artifacts are also demonstrated. Mg-rich defects and variations in N:Ga were found to be independent of artifacts related to the evaporation field in APT.
We study quantum chaos in two dimensional conformal field theories, building on the work analyzing the out-of-time order thermal correlation functions using large-c Virasoro blocks. Our work investigates the contribution of light intermediate channels and smearing length scales to the four-point function and scrambling. Precise relations for how light intermediate channels increase the scrambling time and how smearing length scales smaller than the thermal length scale decrease the scrambling time are derived.
We present near-infrared spectroscopy for 52 ultracool dwarfs, including two newly discovered late-M dwarfs, one new late-M subdwarf candidate, three new L and four new T dwarfs. We also present parallaxes and proper motions for 21 of them. Four of the targets presented here have previous parallax measurements, while all the others are new values. This allow us to populate further the spectral sequence at early types (L0-L4). Combining the astrometric parameters with the new near-infrared spectroscopy presented here, we are able to investigate further the nature of some of the objects. In particular, we find that the peculiar blue L1 dwarf SDSS J133148.92-011651.4 is a metal-poor object, likely a member of the galactic thick disk. We discover a new M subdwarf candidate, 2MASS J20115649-6201127. We confirm the low-gravity nature of EROS-MP J0032-4405, DENIS-P J035726.9-441730, and 2MASS J22134491-2136079. We present two new metal-poor dwarfs: the L4pec 2MASS J19285196-4356256 and the M7pec SIPS2346-5928. We also determine the effective temperature and bolometric luminosity of the 21 targets with astrometric measurements, and we obtain a new polynomial relation between effective temperature and near-infrared spectral type. The new fit suggests a flattening of the sequence at the transition between M and L spectral types. This could be an effect of dust formation, that causes a more rapid evolution of the spectral features as a function of the effective temperature.