ShantanuT01/DACTYL-Pretraining huggingface dataset:
We present a new effective-one-body (EOB) Hamiltonian with next-to-leading order (NLO) spin-spin coupling for black hole binaries endowed with arbitrarily oriented spins. The Hamiltonian is based on the model for parallel spins and equatorial orbits developed in [Physical Review D 90, 044018 (2014)], but differs from it in several ways. In particular, the NLO spin-spin coupling is not incorporated by a redefinition of the centrifugal radius $r_c$, but by separately modifying certain sectors of the Hamiltonian, which are identified according to their dependence on the momentum vector. The gauge-fixing procedure we follow allows us to reduce the 25 different terms of the NLO spin-spin Hamiltonian in Arnowitt-Deser-Misner coordinates to only 9 EOB terms. This is an improvement with respect to the EOB model recently proposed in [Physical Review D 91, 064011 (2015)], where 12 EOB terms were involved. Another important advantage is the remarkably simple momentum structure of the spin-spin terms in the effective Hamiltonian, which is simply quadratic up to an overall square root. Moreover, a Damour-Jaranowski-Sch\"afer-type gauge could be established, thus allowing one to concentrate, in the case of circular and equatorial orbits, the whole spin-spin interaction in a single radial potential.
We calculate the dynamical conductivity of AA-stacked bilayer graphene as a function of frequency and in the presence of a finite chemical potential due to charging. Unlike the monolayer, we find a Drude absorption at charge neutrality in addition to an interband absorption with onset of twice the interlayer hopping energy. At finite doping, the interband absorption exhibits two edges which depend on both chemical potential and interlayer hopping energy. We study the behaviour as a function of varying chemical potential relative to the interlayer hopping energy scale and compute the partial optical sum. The results are contrasted with the previously published case of AB-stacking. While we focus on in-plane conductivity, we also provide the perpendicular conductivity for both AB and AA stacking. We also examine conductivity for other variations with AA-stacking, such as AAA-stacked trilayer. Based on proposed models for topological insulators discussed in the literature, we also consider the effect of spin orbit coupling on the optical properties of an AA-stacked bilayer which illustrates the effect of an energy gap opening at points in the band structure.
We demonstrate that, in the context of the $\Lambda$CDM model, it is in principle possible to measure the value of the cosmological constant by tracing, across cosmic time, the evolution of the turnaround radius of cosmic structures. The novelty of the presented method is that it is local, in the sense that it uses the effect of the cosmological constant on the relatively short scales of cosmic structures and not on the dynamics of the Universe at its largest scales. In this way, it can provide an important consistency check for the standard cosmological model and can give signs of new physics, beyond $\Lambda$CDM.
Hertz-Moriya-Millis theory with dynamical critical exponent $z = 2$ has been proposed to describe antiferromagnetic quantum criticality in itinerant electron systems. In this study we show that the dynamical critical exponent changes from $z = 2$ to $z = 3$ at low temperatures, which results from effective long-range interactions between spin fluctuations, generated by Fermi-surface fluctuations beyond the Eliashberg framework. We claim that the underlying physics for the $z = 3$ antiferromagnetic quantum criticality is the emergence of fermionized skyrmion excitations at low energies, which form a Fermi surface, referred as a skyrmion liquid, where the interplay between itinerant electrons and skyrmions is argued to allow fermionized skyrmions. We construct a dual field theory in terms of skyrmion excitations, and obtain the $z = 3$ antiferromagnetic quantum criticality. This demonstration suggests the expected but nontrivial consistency between weak-coupling and strong-coupling theories.
How best to design and redesign high-throughput experiments for zeolite synthesis is addressed. A model that relates materials function to chemical composition of the zeolite and the structure directing agent is introduced. Using this model, several Monte Carlo-like design protocols are evaluated. Multi-round protocols are found to be effective, and strategies that use a priori information about the structure-directing libraries are found to be the best.
We study a Newtonian cosmological model in the context of a noncommutative space. It is shown that the trajectories of a test particle undergo modifications such that it no longer satisfies the cosmological principle. For the case of a positive cosmological constant, spiral trajectories are obtained and corrections to the Hubble constant appear. It is also shown that, in the limit of a strong noncommutative parameter, the model is closely related to a particle in a G\"odel-type metric.
We show how the Landau-Ginzburg/Calabi-Yau correspondence for the quintic three-fold can be cast into a global mirror symmetry framework. Then we draw inspiration from Berglund-H\"ubsch mirror duality construction to provide an analogue conjectural picture featuring all Calabi-Yau hypersurfaces within weighted projective spaces and certain quotients by finite abelian group actions.
We report the X-ray pulsation of ~173.3 ms for the "next Geminga", PSR J1836+5925, with recent XMM-Newton investigations. The X-ray periodicity is consistent wtih the gamma-ray ephemeris at the same epoch. The X-ray folded light curve has a sinusoidal structure which is different from the double-peaked gamma-ray pulse profile. We have also analysed the X-ray phase-averaged spectra which shows the X-ray emission from PSR J1836+5925 is thermal dominant. This suggests the X-ray pulsation mainly originates from the modulated hot spot on the stellar surface.
The Klein Gordon equation was the first attempt at unifying special relativity and quantum mechanics. While initially discarded this equation of "many fathers" can be used in understanding spinless particles that consequently led to the discovery of pions and other subatomic particles. The equation leads to the development of Dirac equation and hence quantum field theory. It shows interesting quantum relativistic phenomena like Klein Paradox and "Zitterbewegung", a rapid vibrating movement of quantum relativistic particles. The simulation of such quantum equations initially motivated Feynman to propose the idea of quantum computation. While many such simulations have been done till date in various physical setups, this is the first time a digital quantum simulation of Klein Gordon equation is proposed on IBM's quantum computer. Here we simulate the time-dependent Klein Gordon equation in a barrier potential and clearly observe the tunnelling of the particle and anti-particle through a strong potential claiming Klein Paradox. The simulation technique used here inspires the quantum computing community for further studying Klein Gordon equation and applying it to more complicated quantum mechanical systems.
The color of hot-dip galvanized steel sheet was adjusted in a reproducible way using a liquid Zn-Ti metallic bath, air atmosphere, and controlling the bath temperature as the only experimental parameter. Coloring was found only for sample s cooled in air and dipped into Ti-containing liquid Zn. For samples dipped into a 0.15 wt pct Ti-containing Zn bath, the color remained metallic (gray) below a 792 K (519 C) bath temperature; it was yellow at 814 K, violet at 847 K, and blue at 873 K. With the increasing bath temperature, the thickness of the adhered Zn-Ti layer gradually decreased from 52 to 32 micrometers, while the thickness of the outer TiO2 layer gradually increased from 24 to 69 nm. Due to small Al contamination of the Zn bath, a thin (around 2 nm) alumina-rich layer is found between the outer TiO2 layer and the inner macroscopic Zn layer. It is proven that the color change was governed by the formation of thin outer TiO2 layer; different colors appear depending on the thickness of this layer, mostly due to the destructive interference of visible light on this transparent nano-layer. A complex model was built to explain the results using known relationships of chemical thermodynamics, adhesion, heat flow, kinetics of chemical reactions, diffusion, and optics.
$\mu-e$ conversion is the experimentally most interesting lepton flavor violating process. From a theoretical point of view it is an interesting interplay of particle and nuclear physics. The effective transition operator, depending on the gauge model, is in general described in terms of a combination of four terms of transition operators (isoscalar and isovector, Fermi-like as well as axial vector-like). The experimentally most interesting ground state to ground state transition is adequately described in terms of the usual proton and neutron form factors. These were computed in both the shell model and RPA. Since it is of interest to know the portion of the strength exhausted by the coherent (ground state to ground state) transition, the total transition rate to all final states must also be computed. This was done i) in RPA by explicitly summing over all final states ii) in the context of the closure approximation (using shell model and RPA for constructing the initial state) and iii) in the context of nuclear matter mapped into nuclei via a local density approximation. We found that, apart from small local oscillations, the conversion rate keeps increasing from light to heavy nuclear elements. We also find that the coherent mode is dominant (it exhausts more than 90\% of the sum rule). Various gauge models are discussed. In general the predicted branching ratio is much smaller compared to the present experimental limit.
Wolf 1465 has been suggested as a candidate for a bright dwarf carbon star. It is not.
Recently, liquid-phase crystallization of thin silicon films has emerged as a promising candidate for thin-film photovoltaics. On 10 \mu m thin absorbers, wafer-equivalent morphologies and open-circuit voltages were reached, leading to a record efficiency of 12.1%. However, short-circuit current densities are still limited, mainly due to optical losses at the glass-silicon interface. While nano-structures at this interface have been shown to efficiently reduce reflection, up to now these textures caused an increase in recombination. Therefore, optical gains were mitigated due to electronic losses. Here, the SMooth Anti-Reflective Three-dimensional (SMART) texture is introduced in order to overcome this trade-off. By smoothing nanoimprinted SiOx nano-pillar arrays with spin-coated TiOx layers, light-trapping properties of laser-crystallized silicon solar cells could significantly be improved as successfully shown in three-dimensional simulations and in experiment. At the same time, the smooth surface morphology of SMART textures allows preserving electronic material quality equivalent to that of planar reference samples and reaching Voc values above 640 mV in 8 \mu m thin liquid-phase crystallized silicon solar cells. Furthermore, the short-circuit current density jsc could be increased from 21.0 mA cm-2 for planar reference cells with already optimized anti-reflective interlayer stacks to 23.3 mA cm-2 on SMART textures, corresponding to a relative increase of 11%.
We investigate the transport behavior of finite modular quantum systems. Such systems have recently been analyzed by different methods. These approaches indicate diffusive behavior even and especially for finite systems. Inspired by these results we analyze analytically and numerically if and in which sense the dynamics of those systems are in agreement with an appropriate Boltzmann equation. We find that the transport behavior of a certain type of finite modular quantum systems may indeed be described in terms of a Boltzmann equation. However, the applicability of the Boltzmann equation appears to be rather limited to a very specific type of model.
We consider the Glauber dynamics for model of polymer interacting with a substrate or wall. The state space is the set of one-dimensional nearest-neighbor paths on $\mathbb{Z}$ with nonnegative integer coordinates, starting at $0$ and coming back to $0$ after $L$ ($L\in 2\mathbb{N}$) steps and the Gibbs weight of a path $\xi=(\xi_x)^{L}_{x=0}$ is given by $\lambda^{\mathcal{N}(\xi)}$, where $\lambda \geq 0$ is a parameter which models the intensity of the interaction with the substrate and $\mathcal{N}(\xi)$ is the number of zeros in $\xi$. The dynamics we consider proceeds by updating $\xi_x$ with rate one for each $x=1,\dots, L-1$, in a heat-bath fashion. This model was introduced in [CMT08] with the aim of studying the relaxation to equilibrium of the system.   We present new results concerning the total variation mixing time for this dynamics when $\lambda< 2$, which corresponds to the phase where the effects of the wall's entropic repulsion dominates. For $\lambda \in [0, 1]$, we prove that the total variation distance to equilibrium drops abruptly from $1$ to $0$ at time $(L^2 \log L)(1+o(1))/\pi^2$. For $\lambda \in (1,2)$, we prove that the system also exhibit cutoff at time $(L^2 \log L)(1+o(1))/\pi^2$ when considering mixing time from "extremal conditions" (that is, either the highest or lowest initial configuration for the natural order on the set of paths). Our results improves both previously proved upper and lower bounds in [CMT08].
The quasi-one-dimensional bond-alternating S=1 quantum antiferromagnet NTENP is studied by single crystal inelastic neutron scattering. Parameters of the measured dispersion relation for magnetic excitations are compared to existing numerical results and used to determine the magnitude of bond-strength alternation. The measured neutron scattering intensities are also analyzed using the 1st-moment sum rules for the magnetic dynamic structure factor, to directly determine the modulation of ground state exchange energies. These independently determined modulation parameters characterize the level of spin dimerization in NTENP. First-principle DMRG calculations are used to study the relation between these two quantities.
Underwater images are inevitably affected by color distortion and reduced contrast. Traditional statistic-based methods such as white balance and histogram stretching attempted to adjust the imbalance of color channels and narrow distribution of intensities a priori thus with limited performance. Recently, deep-learning-based methods have achieved encouraging results. However, the involved complicate architecture and high computational costs may hinder their deployment in practical constrained platforms. Inspired by above works, we propose a statistically guided lightweight underwater image enhancement network (USLN). Concretely, we first develop a dual-statistic white balance module which can learn to use both average and maximum of images to compensate the color distortion for each specific pixel. Then this is followed by a multi-color space stretch module to adjust the histogram distribution in RGB, HSI, and Lab color spaces adaptively. Extensive experiments show that, with the guidance of statistics, USLN significantly reduces the required network capacity (over98%) and achieves state-of-the-art performance. The code and relevant resources are available at https://github.com/deepxzy/USLN.
Style synthesis attracts great interests recently, while few works focus on its dual problem "style separation". In this paper, we propose the Style Separation and Synthesis Generative Adversarial Network (S3-GAN) to simultaneously implement style separation and style synthesis on object photographs of specific categories. Based on the assumption that the object photographs lie on a manifold, and the contents and styles are independent, we employ S3-GAN to build mappings between the manifold and a latent vector space for separating and synthesizing the contents and styles. The S3-GAN consists of an encoder network, a generator network, and an adversarial network. The encoder network performs style separation by mapping an object photograph to a latent vector. Two halves of the latent vector represent the content and style, respectively. The generator network performs style synthesis by taking a concatenated vector as input. The concatenated vector contains the style half vector of the style target image and the content half vector of the content target image. Once obtaining the images from the generator network, an adversarial network is imposed to generate more photo-realistic images. Experiments on CelebA and UT Zappos 50K datasets demonstrate that the S3-GAN has the capacity of style separation and synthesis simultaneously, and could capture various styles in a single model.
Supersymmetric models with an approximate CP, $10^{-3} \lsim \phi_{CP} \ll 1$, are a viable framework for the description of nature. The full high energy theory has exact CP and horizontal symmetries that are spontaneously broken with a naturally induced hierarchy of scales, $\Lambda_{CP} \ll \Lambda_{H}$. Consequently, the effective low energy theory, that is the supersymmetric Standard Model, has CP broken explicitly but by a small parameter. The $\epsilon_{K}$ parameter is accounted for by supersymmetric contributions. The predictions for other CP violating observables are very different from the Standard Model. In particular, CP violating effects in neutral B decays into final CP eigenstates such as $B \to \psi K_{S}$ and in $K \to \pi\nu\bar{\nu}$ decays are very small. This framework, though, is strongly disfavored by the recent measurements of $\epsilon^\prime_{K}/\epsilon_{K}$.
The Galactic Center supermassive black hole Sagittarius A* (Sgr A*) is one of the most promising targets to study the dynamics of black hole accretion and outflow via direct imaging with very long baseline interferometry (VLBI). At 3.5 mm (86 GHz), the emission from Sgr A* is resolvable with the Global Millimeter VLBI Array (GMVA). We present the first observations of Sgr A* with the phased Atacama Large Millimeter/submillimeter Array (ALMA) joining the GMVA. Our observations achieve an angular resolution of ~87{\mu}as, improving upon previous experiments by a factor of two. We reconstruct a first image of the unscattered source structure of Sgr A* at 3.5 mm, mitigating effects of interstellar scattering. The unscattered source has a major axis size of 120 $\pm$ 34{\mu}as (12 $\pm$ 3.4 Schwarzschild radii), and a symmetrical morphology (axial ratio of 1.2$^{+0.3}_{-0.2}$), which is further supported by closure phases consistent with zero within 3{\sigma}. We show that multiple disk-dominated models of Sgr A* match our observational constraints, while the two jet-dominated models considered are constrained to small viewing angles. Our long-baseline detections to ALMA also provide new constraints on the scattering of Sgr A*, and we show that refractive scattering effects are likely to be weak for images of Sgr A* at 1.3 mm with the Event Horizon Telescope. Our results provide the most stringent constraints to date for the intrinsic morphology and refractive scattering of Sgr A*, demonstrating the exceptional contribution of ALMA to millimeter VLBI.
We study theoretically the spin-dependent transport in ferromagnet/normal-metal/ferromagnet double tunnel junctions by special attention to cotunneling in the Coulomb blockade region. The spin accumulation caused by cotunneling squeezes the Coulomb blockade region when the magnetizations in the ferromagnetic electrodes are antiparallel. Outside the squeezed Coulomb blockade region, we propose a new anomalous region, where the sequential tunneling in one of the spin bands is suppressed by the Coulomb blockade and that in the other is not. In this region, the tunnel magnetoresistance oscillates as a function of bias voltage. The temperature dependences of the tunnel magnetoresistance and the magnitude of the spin accumulation are calculated.
This article is concerned with the study of weak solutions of a linear transport equation on a bounded domain with coupled boundary data for general non smooth space and time dependent velocity fields. The existence of solutions, its uniqueness and the continuous dependence of the solution on the initial and boundary data as well on the velocity is proven. The results are based on the renormalization property. At the end, the theory is shown to be applicable to the continuity equation on a network.
We investigate a shape optimization problem of the Polya-Szego type and prove some results on symmetry and asymmetry of extremal domains.
I outline a mechanism, akin to Weibel instabilities of interpenetrating beams, in which the neighboring current sheets in a striped wind from an oblique rotator interact through a two stream-like mechanism (a Weibel instability in flatland), to create an anomalous resistivity that heats the sheets and causes the magnetic field to diffusively annihilate in the wind upstream of the termination shock. The heating has consequences for observable unpulsed emission from pulsars.
A survey paper, to appear as a chapter in a forthcoming Handbook on Enumeration.
The recent TJLAB experimental data on inclusive electron scattering at high momentum transfer from complex nuclei are analyzed in terms of y-scaling, taking into account the final state interaction (FSI) of the struck, off-shell nucleon. It is shown that at large negative values of y (x>1), the Q^2 dependence of the FSI is mostly driven by the elastic nucleon-nucleon cross section, and that, as a result, the scaling function decreases with Q^2, in agreement with experimental data.
We study the time-asymptotic behavior of linear hyperbolic systems under partial dissipation which is localized in suitable subsets of the domain. More precisely, we recover the classical decay rates of partially dissipative systems satisfying the stability condition (SK) with a time-delay depending only on the velocity of each component and the size of the undamped region. To quantify this delay, we assume that the undamped region is a bounded space-interval and that the system without space-restriction on the dissipation satisfies the stability condition (SK). The former assumption ensures that the time spent by the characteristics of the system in the undamped region is finite and the latter that whenever the damping is active the solutions decay. Our approach consists in reformulating the system into n coupled transport equations and showing that the time-decay estimates are delayed by the sum of the times each characteristics spend in the undamped region.
We studied the role of the tensor interaction in He isotopes systematically on the basis of the tensor-optimized shell model (TOSM). We use a bare nucleon-nucleon interaction AV8 obtained from nucleon-nucleon scattering data. The short-range correlation is treated in the unitary correlation operator method (UCOM). Using the TOSM+UCOM approach, we investigate the role of tensor interaction on each spectrum in He isotopes. It is found that the tensor interaction enhances the LS splitting energy observed in 5He, in which the p1/2 and p3/2 orbits play different roles on the tensor correlation. In {6,7,8}He, the low-lying states containing extra neutrons in the p3/2 orbit gain the tensor contribution. On the other hand, the excited states containing extra neutrons in the p1/2 orbit lose the tensor contribution due to the Pauli-blocking effect with the 2p2h states in the 4He core configuration.