Temperature Dependence of the Gibbs State in the Random Energy Model

We consider the problem of temperature dependence of the Gibbs states in two spin-glass models: Derrida's Random Energy Model and its analogue, where the random variables in the Hamiltonian are replaced by independent standard Brownian motions. For both of them we compute in the thermodynamic limit the overlap distribution ^N _{i=1 i i} /N[–1,1] of two spin configurations , under the product of two Gibbs measures, which are taken at temperatures T,T respectively. If TT are fixed, then at low temperature phase the results are different for these models: for the first one this distribution is D _{0 0}+D _{1 1}, with random weights D ₀, D ₁, while for the second one it is ₀. We compute consequently the overlap distribution for the second model whenever T–T0 at different speeds as N.     

Lattice mechanical properties of some fcc f-shell metals

A pseudopotential depending on an effective core radius is proposed to study the binding energy, equation of state, ion-ion interaction, phonon dispersion curves (q-space and r-space analysis), mode Grüneisen parameters and dynamical elastic constants of some fcc f-shell metals La, Yb, Ce and Th. The contribution of the s-like electrons is calculated in the second-order perturbation theory for the potential while d and f-like electron is taken into account by introducing repulsive short-range Born-Mayer term. The parameter of the potential is evaluated by zero pressure condition. An excellent agreement between theoretical investigations and experimental findings is achieved which confirms the present formalism     

Feedback controlled periodic states for different kinds of photorefractive nonlinear response

We investigate analytically and numerically the influence of the type of the photorefractive nonlinear response on the periodic states (attractors) which occur during feedback controlled 2W-coupling and correspond to almost 100% diffraction efficiency of the dynamic index grating. In addition to the case of the local response typical, for example, for LiNbO₃ crystals we consider the cases of nonlocal (diffusive) response (BaTiO₃, SBN) and resonant response (DC-biased BSO, BTO, and BGO crystals). It is shown that the conditions for the transition to the periodic states and their apparent characteristics are strongly different for the two limiting cases above. Received 16 July 2002 / Received in final form 29 October 2002 Published online 4 March 2003     

Pre-equilibrium dipole strength in charge asymmetric peripheral heavy-ion reactions

We report on the results obtained from the study of the ³²S + ⁶⁴Ni and ³²S + ⁵⁸Ni peripheral reactions at incident energies E _lab = 288 MeV and E _lab = 320 MeV, respectively. High-energy γ-rays were detected in an array of 8 seven-pack BaF₂ clusters. Coincidence with complex fragments detected in 12 three-stage telescopes ensured the selection of peripheral reaction events. All of the relevant reaction parameters were kept constant with the exception of the different initial dipole moment caused by the different entrance channel charge asymmetry. While for quasi-elastic events no N/Z effect was observed in the differential γ-ray multiplicities of the two reactions, for deep-inelastic events a larger dipole γ-ray emission occurs during the more N/Z asymmetric reaction. A theoretical interpretation based on a collective Bremsstrahlung analysis of the reaction dynamics is presented. Received: 26 September 2002 / Accepted: 13 November 2002 / Published online: 6 March 2003 RID="a" ID="a"e-mail: pierroutsakou@na.infn.it RID="b" ID="b"Present address: INFN, Laboratori Nazionali di Legnaro, Padova, Italy. Communicated by C. Signorini     

Nonperturbative Operator Quantization of Strongly Nonlinear Fields

At present an algebra of strongly interacting fields is unknown. In this paper it is assumed that the operators of a strongly nonlinear field can form a non-associative algebra. It is shown that such an algebra can be described as an algebra of some pairs. The comparison of presented techniques with the Green's functions method in superconductivity theory is made. A possible application to the QCD and High-T _c superconductivity theory is discussed.     

新模式热电联产系统:联产供热的一个发展

1前言经济的迅猛发展，能源与水源的供需矛盾的突出，环保形势的严峻要求用能的“文明化”。文明用能应是跨世纪和新世纪用能战略的基本原则。文明用能的一个极重要方面就是对热能的文明利用问。热电联产是热能文明利用不可替代的途径。本文提出一种热电联产的新模式，旨在通过这种模式把联产供热规模化，大幅度地节约能源和水资源，减轻电能与热能的生产对环境的不利影响。最近中央提出的可持续发展战略，应成为我们今后技术研究的一个指导性方针。节约能源、水源和保护环境是这一战略的重要组成部分。在世界范围内，对节约资源保护环境问…     

双原子分子振动能级半量子化及量子理论的数值计算

利用半经典量子化理论和量子理论，分别采用Ｌｅｎｎａｒｄ－Ｊｏｎｅｓ势和Ｍｏｒｓｅ势，对双原子分子的振动能级给予了较为详细的数值计算。并将所得结果与部分实验数据进行比较，峄双原子分子的振动能级作了较为详细的 讨论。     

布里渊区内能带E(k)=E(-k)的对称性

说明了布里渊区内能带Ｅ（ｋ）＝Ｅ（－ｋ）的对称性是时间反演对称性的结果，而与晶体的空间对称性无关．并且证明了当晶体具有中心反演对称性时，布里渊区内能带是二重简并的．     

随机共振研究进展

全面介绍了随机共振的概念、机理、理论和实验研究的主要进展及研究现状，对随机共振研究的可能应用也做了富有建设意义的展望性介绍。     

三维各向同性谐振子的代数解法

用带角动量的玻色算子统一构成三维各向同性谐振子的能量本征函数，并讨论了它们和直接求解微分方程得到的本征解之间的关系．这种方法快捷优美，而且有统一的表达式和简单的李代数关系。