ShantanuT01/DACTYL-Pretraining huggingface dataset:
The channeling of the ion recoiling after a collision with a WIMP in direct dark matter crystalline detectors produces a larger scintillation or ionization signal than otherwise expected. Channeling is a directional effect which depends on the velocity distribution of WIMPs in the dark halo of our Galaxy and could lead to a daily modulation of the signal. Here we compute upper bounds to the expected amplitude of daily modulation due to channeling using channeling fractions that we obtained with analytic models in prior work. After developing the general formalism, we examine the possibility of finding a daily modulation due to channeling in the data already collected by the DAMA/NaI and DAMA/LIBRA experiments. We find that even the largest daily modulation amplitudes (of the order of 10% in some instances) would not be observable for WIMPs in the standard halo in the 13 years of data taken by the DAMA collaboration. For these to be observable the DAMA total rate should be 1/40 of what it is or the total DAMA exposure should be 40 times larger. The daily modulation due to channeling will be difficult to measure in future experiments. We find it could be observed for light WIMPs in solid Ne, assuming no background.
We present the selection, spectroscopic identification, and physical properties of extreme emission line galaxies (EELGs) at $3<z<3.7$ aiming at studying physical properties of an analog population of star-forming galaxies (SFGs) at the epoch of reionization. The sample is selected based on the excess in the observed Ks broad band flux relative to the best-fit stellar continuum model flux. By applying a 0.3 mag excess as a primary criterion, we select 240 EELG candidates with intense emission lines and estimated observed-frame equivalent width (EW) of $\gtrsim 1000$ angstrom over the UltraVISTA-DR2 ultra-deep stripe in the COSMOS field. We then carried out a HK band follow-up spectroscopy for 23 of the candidates with Subaru/MOIRCS, and find that 19 and two of them are at $z>3$ with intense [OIII] emission, and H$\alpha$ emitters at $z\simeq 2$, respectively. These spectroscopically identified EELGs at $z\simeq 3.3$ show, on average, higher specific star formation rates (sSFR) than the star-forming main sequence, low dust attenuation of $E(B-V) \lesssim 0.1$ mag, and high [OIII]/[OII] ratios of $\gtrsim 3$. We also find that our EELGs at $z\simeq 3.3$ have higher hydrogen ionizing photon production efficiencies ($\xi_\mathrm{ion}$) than the canonical value ($\simeq 10^{25.2}$ Hz/erg), indicating that they are efficient in ionizing their surrounding interstellar medium. These physical properties suggest that they are low metallicity galaxies with higher ionization parameters and harder UV spectra than normal SFGs, which is similar to galaxies with Lyman continuum (LyC) leakage. Among our EELGs, those with the largest [OIII]/[OII] and EW([OIII]) values would be the most promising candidates to search for LyC leakage.
Using a statistical sample of dark matter haloes drawn from a suite of cosmological N-body simulations of the Cold Dark Matter (CDM) model, we quantify the impact of a simulated halo's mass accretion and merging history on two commonly used measures of its dynamical state, the virial ratio eta and the centre of mass offset Delta r. Quantifying this relationship is important because the degree to which a halo is dynamically equilibrated will influence the reliability with which we can measure characteristic equilibrium properties of the structure and kinematics of a population of haloes. We begin by verifying that a halo's formation redshift zform correlates with its virial mass Mvir and we show that the fraction of its recently accreted mass and the likelihood of it having experienced a recent major merger increases with increasing Mvir and decreasing zform. We then show that both eta and Delta r increase with increasing Mvir and decreasing zform, which implies that massive recently formed haloes are more likely to be dynamically unrelaxed than their less massive and older counterparts. Our analysis shows that both eta and Delta r are good indicators of a halo's dynamical state, showing strong positive correlations with recent mass accretion and merging activity, but we argue that Delta r provides a more robust and better defined measure of dynamical state for use in cosmological N-body simulations at z~0. We find that Delta r < 0.04 is sufficient to pick out dynamically relaxed haloes at z=0. Finally, we assess our results in the context of previous studies, and consider their observational implications.
We investigate the Abelian projection with respect to the Polyakov loop operator for SU(N) gauge theories on the four torus. The gauge fixed $A_0$ is time-independent and diagonal. We construct fundamental domains for $A_0$. In sectors with non-vanishing instanton number such gauge fixings are always singular. The singularities define the positions of magnetically charged monopoles, strings or walls. These magnetic defects sit on the Gribov horizon and have quantized magnetic charges. We relate their magnetic charges to the instanton number.
The rigorous explanation for the term $| t |^{2\beta}$ in the rectilinear diameter equation is given ($t = (T_c-T)/T_c$, $\beta$ is the critical exponent for the asymptotic form of the equation of state). The optimal order parameter, for which the branches of binodal are symmetric is constructed within the canonical formalism. It is shown that the ratio of the amplitudes $\f{D_{2\beta}}{D_{1-\alpha}}$ before $|t|^{2\beta}$ and $|t|^{1-\alpha}$ where $\alpha$ determines the behavior of the heat capacity, takes the universal character. The analysis of entropy for argon and water leads to $\beta = 0.33$ and $\f{D_{2-\beta}}{{D_{1-\alpha}}}\approx - 3.5$.
Recent work has shown that Milky Way-mass galaxies display an incredible range of stellar halo properties, yet the origin of this diversity is unclear. The nearby galaxy M81 $-$ currently interacting with M82 and NGC 3077 $-$ sheds unique light on this problem. We present a Subaru Hyper Suprime-Cam survey of the resolved stellar populations around M81, revealing M81's stellar halo in never-before-seen detail. We resolve the halo to unprecedented $V$-band equivalent surface brightnesses of 33 mag arcsec$^{-2}$, and produce the first-ever global stellar mass density map for a Milky Way-mass stellar halo outside of the Local Group. Using the minor axis, we confirm M81's halo as one of the lowest mass and metal-poorest known ($M_{\star} \simeq 1.16{\times}10^9 M_{\odot}$, [Fe/H] $\simeq {-}1.2$) $-$ indicating a relatively quiet prior accretion history. Yet, our global halo census finds that tidally unbound material from M82 and NGC 3077 provides a substantial infusion of metal-rich material ($M_{\star} \simeq 5.4{\times}10^8$ $M_{\odot}$, [Fe/H] $\simeq {-}$0.9). We further show that, following the accretion of its massive satellite M82 (and the LMC-like NGC 3077), M81 will host one of the most massive and metal-rich stellar halos in the nearby universe. Thus, the saga of M81: following a passive history, M81's merger with M82 will completely transform its halo from a low-mass, anemic halo rivaling the MW, to a metal-rich behemoth rivaled only by systems such as M31. This dramatic transformation indicates that the observed diversity in stellar halo properties is primarily driven by diversity in the largest mergers these galaxies have experienced.
Let $X$ be an irreducible symmetric Markov process with the strong Feller property. We assume, in addition, that $X$ is explosive and has a tightness property. We then prove the existence and uniqueness of quasi-stationary distributions of $X$.
Traditionally, the theory related to the spatial angular momentum has been studied completely, while the investigation in the generator of Lorentz boost is inadequate. In this paper we show that the generator of Lorentz boost has a nontrivial physical significance, it endows a charged system with an electric moment, and has an important significance for the electrical manipulations of electron spin in spintronics. An alternative treatment and interpretation for the traditional Darwin term and spin-orbit coupling are given.
Magnetars are proposed to be peculiar neutron stars which could power their X-ray radiation by super-strong magnetic fields as high as $\gtrsim 10^{14}$ G. However, no direct evidence for such strong fields is obtained till now, and the recent discovery of low magnetic field magnetars even indicates that some more efficient radiation mechanism than magnetic dipole radiation should be included. In this paper, quantum vacuum friction (QVF) is suggested to be a direct consequence of super-strong {\em surface} fields, therefore the magnetar model could then be tested further through the QVF braking. Pulsars' high surface magnetic field interacting with the quantum vacuum result in a significantly high spindown rate ($\dot{P}$). It is found that QVF dominates the energy loss of pulsars when pulsar's rotation period and its first derivative satisfy the relationship $P^3\cdot \dot{P}>0.63\times10^{-16}\xi^{-4}$s$^2$, where $\xi$ is the ratio of the surface magnetic field over diploe magnetic field. In the "QVF $+$ magnetodipole" joint braking scenario, the spindown behavior of magnetars should be quite different from that in the pure magnetodipole model. We are expecting these results could be tested by magnetar candidates, especially the low magnetic field ones, in the future.
We study the adsorption of chlorine on the Ag(111) surface with full potential gradient corrected density functional calculations. When considering a root3 x root3 R30degree pattern, we find that the fcc hollow is the most favorable adsorption site. We obtain an Ag-Cl bond length of 2.62 Angstrom which is intermediate between two controversial experimental results. We discuss the differences of core level energies and densities of states for the different adsorption sites. We find the Cl-Ag interaction to be more consistent with an ionic, rather than covalent, picture of the bonding. In addition, we compute energetics and related properties of Ag bulk and the clean Ag surface comparing the local density approximation and the generalized gradient approximation.
We have developed a new model of the Doppler tomography using total variation minimization (DTTVM). This method can reconstruct localized and non-axisymmetric profiles having sharp edges in the Doppler map. This characteristic is emphasized in the case that the number of the input data is small. We apply this model to real data of the dwarf novae, WZ Sge in superoutburst and TU Men in quiescence. We confirmed that DTTVM can reproduce the observed spectra with a high precision. Compared with the models based on the maximum entropy method, DTTVM provides the Doppler maps that little depend on the hyper-parameter and on the presence of the absorption core. We also introduce a cross-validation method to estimate reasonable values of a hyperparameter in the model by the data itself.
The idea of the metaplectic theta function was introduced by Tomio Kubota in the 1960s. These theta functions are constructed as residues of Eisenstein series and are only known completely in the case of double covers and, up to the ambiguity of a constant, for triple covers. In 1992 Jeff Hoffstein published formulae by which these can be computed in certain cases over a rational function field. The author gave an alternative approach in 2007. Both of these methods give the coefficients in a closed form. The rational function field is unusual in that it has a large automorphism group. In this paper we show that this group has an operation on the coefficients. This operation is not visible from the explicit formulae.
We show that, up to linear equivalence, there are only finitely many polynomial quadratic mappings $F:\mathbb{C}^2\to\mathbb{C}^n$ and $F:\mathbb{R}^2\to\mathbb{R}^n$. We list all possibilities.
We present a novel strategy to systematically study complex-structure moduli stabilization in Type IIB and F-theory flux compactifications. In particular, we determine vacua in any asymptotic regime of the complex-structure moduli space by exploiting powerful tools of asymptotic Hodge theory. In a leading approximation the moduli dependence of the vacuum conditions are shown to be polynomial with a dependence given by sl(2)-weights of the fluxes. This simple algebraic dependence can be extracted in any asymptotic regime, even though in nearly all asymptotic regimes essential exponential corrections have to be present for consistency. We give a pedagogical introduction to the sl(2)-approximation as well as a detailed step-by-step procedure for constructing the corresponding Hodge star operator. To exemplify the construction, we present a detailed analysis of several Calabi-Yau three- and fourfold examples. For these examples we illustrate that the vacua in the sl(2)-approximation match the vacua obtained with all polynomial and essential exponential corrections rather well, and we determine the behaviour of the tadpole contribution of the fluxes. Finally, we discuss the structure of vacuum loci and their relations to several swampland conjectures. In particular, we comment on the realization of the so-called linear scenario in view of the tadpole conjecture.
X-ray reflection is a very powerful method to assess the spin of supermassive black holes (SMBHs) in active galactic nuclei (AGN), yet this technique is not universally accepted. Indeed, complex reprocessing (absorption, scattering) of the intrinsic spectra along the line of sight can mimic the relativistic effects on which the spin measure is based. In this work, we test the reliability of SMBH spin measurements that can currently be achieved through the simulations of high-quality XMM-Newton and NuSTAR spectra. Each member of our group simulated ten spectra with multiple components that are typically seen in AGN, such as warm and (partial-covering) neutral absorbers, relativistic and distant reflection, and thermal emission. The resulting spectra were blindly analysed by the other two members. Out of the 60 fits, 42 turn out to be physically accurate when compared to the input model. The SMBH spin is retrieved with success in 31 cases, some of which (9) are even found among formally inaccurate fits (although with looser constraints). We show that, at the high signal-to-noise ratio assumed in our simulations, neither the complexity of the multi-layer, partial-covering absorber nor the input value of the spin are the major drivers of our results. The height of the X-ray source (in a lamp-post geometry) instead plays a crucial role in recovering the spin. In particular, a success rate of 16 out of 16 is found among the accurate fits for a dimensionless spin parameter larger than 0.8 and a lamp-post height lower than five gravitational radii.
Correlation beyond entanglement is a subject of interest in quantum information. Here we have shown the existence of quantum correlation without entanglement in Heisenberg $XYZ$ spin model with external magnetic field, using different versions of measurement-induced nonlocality. However maximally entangled states are shown to possess maximum correlation.
We investigate the conditions under which the first low-mass stars formed in the universe by confronting theoretical predictions governing the transition from massive Population III to low-mass Population II stars with recent observational C and/or O abundance data of metal-poor Galactic stars. Based on an existing theory, we introduce a new "observer-friendly" function, the transition discriminant D_trans, which provides empirical constraints as well as a powerful comparison between the currently available data of metal-poor halo stars and theoretical predictions of the formation of the first low-mass stars (<1 M_sun). Specifically, we compare the empirical stellar results with the theory that fine-structure lines of C and O dominate the transition from Pop III to Pop II in the early universe. We find the observational data for halo objects as well as for dSph galaxies and globular clusters to be consistent with this theory. An explanation for the observed lack of metal-poor stars in dSph galaxies and globular clusters is also suggested. Finally, we predict that any star to be found with [Fe/H]<-4 should have enhanced C and/or O abundances. The high C and O abundances of the two most iron-poor stars are in line with our prediction.
Widespread adoption of superconducting technologies requires the discovery of new materials with enhanced properties, especially higher superconducting transition temperatures T$_{c}$. The unexpected discovery of high T$_{c}$ superconductivity in cuprates and in materials as diverse as heavy fermions, organic conductors, and endohedrally-doped fullerenes suggests that the highest T$_{c}$s occur when pressure or doping transform the localized and moment-bearing electrons in antiferromagnetic insulators into itinerant and weakly magnetic metals. The absence of this delocalization transition in Fe-based superconductors may limit their T$_{c}$s, but even larger T$_{c}$s may be possible in their isostructural Mn analogs, which are antiferromagnetic insulators like the cuprates. It is generally believed that prohibitively large pressures would be required to suppress the strong Hund's rule coupling in these Mn-based compounds, collapsing the insulating gap and enabling superconductivity. Indeed, no Mn-based compounds are known to be superconductors. The electronic structure calculations and x-ray diffraction measurements presented here challenge these long held beliefs, finding that only modest pressures are required to transform LaMnPO, isostructural to superconducting host LaFeAsO, from an insulating tetragonal structure with a large Mn moment to a gapless orthorhombic structure with a small Mn moment. Proximity to this electronic delocalization transition in LaMnPO results in a highly interacting metallic state, the familiar breeding ground of superconductivity.
A new decoupling scheme is developed for the Hubbard model which provides a unified description of the spin-symmetric (paramagnetic metallic and insulating) phases as well as the broken-symmetry AFI phase. Independent of magnetic ordering, the scheme yields, in the lowest order, the correct strong-coupling bandwidth of order J (for the NN hopping model) and band gap of order U, a non-zero critical interaction strength (above which the band gap opens) only if same sublattice hopping (e.g., NNN hopping) is also present, and the correct integrated spectral weights (1/2 per spin) in each band for the half-filled model. The effects of charge and spin fluctuations, including spin twisting due to finite spin correlation length, are investigated with a static, random approximation. A self-consistent evaluation of the disorder-averaged self energy within the CPA is carried out numerically. Fluctuations activate the hopping term at first order resulting in band broadening, and the consequent decrease in the band gap with fluctuation strength is obtained for several U values in two and three dimensions. We find that the band gap shrinks to zero continuously, and subsequently the density of states N(0) between the bands grows continuously, leading to a continuous metal-insulator transition. For finite doping there is transfer of spectral weight between the Hubbard bands, and a qualitative change in the nature of the quasiparticle band dispersion, with an effective doping-induced hopping strength and bandwidth of order xt.
We examine the behavior of the vortex defects, which are represented by the sine-Gordon potential, on the world-sheet when a solitonic d-5 brane is existing in the d-dimensional target space. The d-5 brane solution is obtained as an extension of 5-brane in 10d supergravity. It is shown that the vortices of any charge should be dissociated to the free gas when they approach to the brane. The meanings of this fact are addressed through the analysis of the renormalization group equations on the world sheet.
We investigate adsorption effects of copper phthalocyanine molecules on excitons and trions in air-suspended carbon nanotubes. Using photoluminescence excitation spectroscopy, we observe that exciton energy redshifts gradually with the molecular deposition thickness. The trion emission is also observed at large deposition amounts, which indicates charge transfer between the phthalocyanine molecules and carbon nanotubes. Analysis of the spectra for individual tubes reveal a correlation between the exciton-trion energy separation and the exciton emission energy, showing that the many-body interaction energies scale similarly with the molecular dielectric screening.
We study the geometry of a two-sheeted space-time within the framework of non-commutative geometry. As a prelude to the Standard Model in curved space-time, we present a model of a left- and a right- chiral field living on the two sheeted-space time and construct the action functionals that describe their interactions.
In this paper we establish several Hardy and Hardy-Sobolev type inequalities with homogeneous weights on the first orthant $\displaystyle \mathbb{R}_{*}^n:=\{(x_1, \ldots, x_n):x_1>0, \ldots, x_n>0 \}$. We then use some of them to produce Hardy type inequalities with remainder terms. Furthermore, we obtain some interpolation inequalities and Maz'ya type inequalities with remainder terms with the help of Maz'ya inequality and Sobolev inequality of Cabr\'e and Ros-Orton on the upper half space $\mathbb{R}_{+}^n:=\{x=(x_1, \ldots, x_n)|\, x_n>0 \}$.
We investigate the intrinsic spin dynamics of electrons bound to Al impurities in bulk ZnO by optical spin noise spectroscopy. Spin noise spectroscopy enables us to investigate the longitudinal and transverse spin relaxation time with respect to nuclear and external magnetic fields in a single spectrum. On one hand, the spin dynamic is dominated by the intrinsic hyperfine interaction with the nuclear spins of the naturally occurring $^{67}$Zn isotope. We measure a typical spin dephasing time of 23 ns in agreement with the expected theoretical values. On the other hand, we measure a third, very high spin dephasing rate which is attributed to a high defect density of the investigated ZnO material. Measurements of the spin dynamics under the influence of transverse as well as longitudinal external magnetic fields unambiguously reveal the intriguing connections of the electron spin with its nuclear and structural environment.
A $k$-orbit map is a map with its automorphism group partitioning the set of flags into $k$ orbits. Recently $k$-orbit maps were studied by Orbani\' c, Pellicer and Weiss, for $k \leq 4$. In this paper we use symmetry type graphs to extend such study and classify all the types of $5$-orbit maps, as well as all self-dual, properly and improperly, symmetry type of $k$-orbit maps with $k\leq 7$. Moreover, we determine, for small values of $k$, all types of $k$-orbits maps that are medial maps. Self-dualities constitute an important tool in this quest.
We combine high-resolution resonant inelastic x-ray scattering with cluster calculations utilizing a recently derived effective magnetic scattering operator to analyze the polarization, excitation energy, and momentum dependent excitation spectrum of the low-dimensional quantum magnet TiOCl in the range expected for orbital and magnetic excitations (0 - 2.5 eV). Ti 3d orbital excitations yield complete information on the temperature-dependent crystal-field splitting. In the spin-Peierls phase we observe a dispersive two-spinon excitation and estimate the inter- and intra-dimer magnetic exchange coupling from a comparison to cluster calculations.
Quantum geometrodynamics with intrinsic time development is presented. Paradigm shift from full space-time covariance to spatial diffeomorphism invariance yields a non-vanishing Hamiltonian, a resolution of the `problem of time', and gauge-invariant temporal ordering in an ever expanding universe. Einstein's general relativity is a particular realization of a wider class of theories; and the framework prompts natural extensions and improvements, with the consequent dominance of Cotton-York potential at early times when the universe was small.