Microscopic basis for Fick's law for self-diffusion

We investigate self-diffusion in a classical fluid composed of two species which are distinguished through the color of their particles, either black or white, but are identical as regards their mechanical properties. Disregarding color the fluid is in thermal equilibrium. We show that if a single test particle in the one-component fluid moves asymptotically as Brownian motion, then the color density and current in certain classes of nonequilibrium states are related, on the appropriate macroscopic scale, through Fick's law, and the former is governed by the diffusion equation. If in addition several test particles move asymptotically as independent Brownian motions, then the colored fluid is, on a macroscopic scale, in local equilibrium with parameters governed by the solution of the diffusion equation.Part of this work was done while both authors were at IHES, Bures-sur-Yvette, France.Supported in part by NSF Grant No. PHY 78-15920-02.Supported by a Heisenberg fellowship of the Deutsche Forschungsgemeinschaft.     

Droplet Phases in Non-local Ginzburg-Landau Models with Coulomb Repulsion in Two Dimensions

We establish the behavior of the energy of minimizers of non-local Ginzburg-Landau energies with Coulomb repulsion in two space dimensions near the onset of multi-droplet patterns. Under suitable scaling of the background charge density with vanishing surface tension the non-local Ginzburg-Landau energy becomes asymptotically equivalent to a sharp interface energy with screened Coulomb interaction. Near the onset the minimizers of the sharp interface energy consist of nearly identical circular droplets of small size separated by large distances. In the limit the droplets become uniformly distributed throughout the domain. The precise asymptotic limits of the bifurcation threshold, the minimal energy, the droplet radii, and the droplet density are obtained.     

Event horizons in static scalar-vacuum space-times

The following theorem is established. Every zero-mass scalar field which is gravitationally coupled, static and asymptotically flat, becomes singular at a simply-connected event horizon. In the special case where the gravitational coupling of the scalar energy density is neglected, the solutions are computed explicitly. Some properties of the singular event horizons are discussed, and a brief mention of related work with non-static scalar fields is given.     

高重复频率激光脉冲作用下KTP晶体中的灰迹

采用波长为1 064 nm/532 nm、脉宽6 ns(FWHM)的高重复频率调Q激光,研究了磷酸氧钛钾(KTP)晶体中灰迹的产生机理,以及色心密度对灰迹的影响。晶体透过率表征了色心密度,根据透过率与色心密度的关系以及色心密度对灰迹产生的决定作用,定义临界灰迹密度,当晶体透过率高于此值时可安全运行,而低于此值时,为避免晶体发生灾难性损伤应立即停止运行。实验结果表明:灰迹不仅大量吸收紫外及可见光能量,而且大量吸收近红外波段能量,这为灰迹的在线监测提供了一种监测方法。     

Ground-state energy of the electron liquid in ultrathin wires

The ground-state energy and the density correlation function of the electron liquid in a thin one-dimensional wire are computed. The calculation is based on an approximate mapping of the problem with a realistic Coulomb interaction law onto exactly solvable models of mathematical physics. This approach becomes asymptotically exact in the limit of a small wire radius but remains numerically accurate even for modestly thin wires.     

Energy diffusion in strongly driven quantum chaotic systems

The energy evolution of a quantum chaotic system under a perturbation that harmonically depends on time is studied in the case of a large perturbation in which the transition rate calculated from the Fermi golden rule exceeds the frequency of the perturbation. It is shown that the energy evolution retains its diffusive character, with a diffusion coefficient that is asymptotically proportional to the magnitude of the perturbation and to the square root of the density of states. The results are supported by numerical calculation. Energy absorption by the system and quantum-classical correlations are discussed. The text was submitted by author in English.     

Cosmological model with interactions in the dark sector

A cosmological model for the present Universe is analyzed whose constituents are a non-interacting baryonic matter field and interacting dark matter and dark energy fields. The dark energy and dark matter are coupled through their effective barotropic indexes, which are considered as functions of the ratio of their energy densities. Two asymptotically stable cases are investigated for the ratio of the dark energy densities which have their parameters adjusted by considering best fits to Hubble function data. It is shown that the deceleration parameter, the density parameters, and the luminosity distance have the correct behavior which is expected for a viable present scenario of the Universe.     

Casimir Effect Under Two Dimensional Black Hole Spacetime Background with Global Monopole

A thin layer of the event horizon vicinity to the two-dimension black hole with a global monopole is considered as a system of the Casimir type. The energy-momentum tensor is derived in Boulware vacuum, Hartle-Hawking vacuum and Unruh vacuum respectively. The values are derived in the massless scalar field which satisfies the Dirichlet boundary conditions. Using the Wald's axioms, the result is got which is the same with the one derived by the usual regularized methods. Meanwhile, the energy, energy density, and pressure acting on the boundaries at the asymptotically flat background also are calculated too, and from the energy, Casimir force is derived. The Casimir energy and Casimir force are compared respectively in the background before and after radiation. PACS: 42.50.Lc.     

Arnowitt-Deser-Misner energy and g00

For a stationary, asymptotically flat space-time the “Komar energy”, associated with the time-like Killing vector and the ADM energy are equal when the latter is evaluated on a Cauchy surface which is asymptotically at rest relative to the Killing vector. The implicationd of this result on the positivity-of-energy problem in General Relativity are discussed.     

Scalar-tensor cosmologies with a potential in the general relativity limit: Time evolution

We consider Friedmann–Lemaître–Robertson–Walker flat cosmological models in the framework of general Jordan frame scalar-tensor theories of gravity with arbitrary coupling function and potential. For the era when the cosmological energy density of the scalar potential dominates over the energy density of ordinary matter, we use a nonlinear approximation of the decoupled scalar field equation for the regime close to the so-called limit of general relativity where the local weak field constraints are satisfied. We give the solutions in cosmological time with a particular attention to the classes of models asymptotically approaching general relativity. The latter can be subsumed under two types: (i) exponential convergence, and (ii) damped oscillations around general relativity. As an illustration we present an example of oscillating dark energy.     

The rotational kinetic energy in the orientationally disordered phase of solid methane. A quasi-classical approach

It is shown that, as a consequence of the orientational correlations, the quantum rotational kinetic energy of interacting molecules in the orientationally disordered phase of solid methane exceeds the free rotor value. The expectation value of kinetic energy is obtained from the initial terms of a quasiclassical high temperature expansion of the free energy. The calculation is based on an analytic function approximating the configuration representation of the statistical density operator of the free spherical top. It is demonstrated that in the classical limit the function tends asymptotically to the true density operator, the error being exponentially dependent on temperature. As an application, the quantum correction to the second moment of an infrared absorption band is estimated.     

Translocation of a confined polymer through a hole

Based on an analogy between polymer translocation across a free energy barrier associated with polymer worming through a hole and classical nucleation and growth process, the escape time tau is predicted asymptotically to be N(N/rho)(1/3nu). N is the polymer length, rho is the monomer density prior to escape, and nu is the radius of gyration exponent. Monte Carlo simulation data collected in the high salt limit (nu approximately 3/5) are in agreement with the asymptotic law and provide vivid details of the escape.     

金红石TiO2晶体中F型色心电子结构及其吸收光谱研究

运用Ｆ型色心的类氢离子波函数结合电荷自洽离散变分法,对ＴｉＯ２晶体中Ｆ型色心的电子结构进行了计算,并利用能量最小原理优化了色心格点周围的Ｔｉ,Ｏ离子结构,得到了ＴｉＯ２晶体中Ｆ,Ｆ＋和Ｆ＾２＋心的能带、态「密度,并讨论了色心的光学跃迁模式,计算结构表明,Ｆ,Ｆ＾＋心在ＴｉＯ２晶体的禁带中引入的旋主能级,Ｆ＾２＋心在禁带中引入了浅受主能级,Ｆ和Ｆ＋心的光学跃有分别是０．８５ｅＣ,１．６７ｅＣ,经还原     

Numerical metric extraction in AdS/CFT

An iterative method for recovering the bulk information in asymptotically AdS spacetimes is presented. We consider zero energy spacelike geodesics and their relation to the entanglement entropy in three dimensions to determine the metric in certain symmetric cases. A number of comparisons are made with an alternative extraction method presented in arXiv:hep-th/0609202, and the two methods are then combined to allow metric recovery in the most general type of static, spherically symmetric setups. We conclude by extracting the mass and density profiles for a toy model example of a gas of radiation in (2 + 1)-dimensional AdS.     

Long range correlations,event simulation and parton percolation

We study the RHIC data on long range rapidity correlations, comparing their main trends with different string model simulations. Particular attention is paid to color percolation model and its similarities with color glass condensate. As both approaches corresponds, at high density, to a similar physical picture, both of them give rise to a similar behavior on the energy and the centrality of the main observables. Color percolation explains the transition from low density to high density.     

石英玻璃低能质子辐照损伤动力学研究

地面模拟研究了JGS3光学石英玻璃在真空、热沉和能量低于200keV的低能质子辐照下表面光学性能变化的基本规律．并建立了辐照损伤色心演化的动力学唯象模型。试验结果表明．大通量低能质子辐照对石英玻璃表层具有明显的表面损伤效应。随着辐照吸收剂量的增加,光密度变化先以线性规律迅速增加．加进一步增加时逐渐呈现饱和趋势;采用较高能量辐照作用后光密度变化出现饱和趋势的拐点提前,且饱和数值降低。根据对试验结果的分析,建立了低能质子辐照下石英玻璃色心演化的动力学模型．并给出了光密度变化的表达式。采用模型结果进行数学模拟,模拟曲线与试验结果曲线相似。因此所建立的动力学模型可以用来定量描述低能质子辐照下石英玻璃光学性能随辐照吸收剂量的变化规律。     

FACTORIZATION OF SUC(3) AT HYPERCOLOR SCALE ∧H AND INDUCED GOLDSTONE BOSONS IN COMPOSITE MODELS

The two possibilities (corresponding to various spontaneous breaking patterns for hyperflavor) for the color group SU_C(3) factorized at the hypercolor scale ∧_H for a kind of composite models are discussed, in which the color inferaction is asymptotically non-free on the preon level, and it is pointed out that the two patterns could be distinguished experimentally by the great difference in number of the induced pseudogoldstones.     

Selection criteria for two-parameter solutions to scalar-tensor gravity

We investigate the generic properties of static, spherically symmetric, asymptotically flat solutions to the field equations describing gravity minimally coupled to a nonlinear self-gravitating real scalar field. Five corollaries and a theorem on selection criteria for two- and one-parametric solutions are proven and conditions for obtaining particle-like solutions, black holes or naked singularities are derived. A series of exact solutions in closed forms including different black holes, naked singularities and particle-like solutions, all of which obey the weak energy condition at spatial infinity, are provided. Two further corollaries elaborate on the behavior of solutions at spatial infinity, critical mass, mass density, pressure and energy conditions.     

On cosmological mass with positive Λ

For asymptotically flat space-times, a very satisfactory expression for the total mass/energy of a system defined at future null infinity was provided by Bondi and Sachs, in the early 1960s. A generalization of this to space-times that are asymptotically de Sitter now has particular relevance in view of observational evidence, from 1998 onwards, indicating the presence of a positive cosmological constant Λ. In this article, some of the issues involved in such a definition are examined, showing that a somewhat different attitude to mass/energy must be taken, from that which was appropriate for asymptotically flat space-times. Two tentative suggestions are put forward for a retarded mass/energy definition with positive Λ, one based on a conformally invariant integral expression whose advanced time-derivative gives the Bondi–Sachs definition in the asymptotically flat case and the other, on the author’s 1982 approach to quasi-local energy. Such expressions could have some direct relevance to the proposal of Conformal Cyclic Cosmology, for which recent analysis of the CMB has provided some striking support.