凝聚态物理
Using numerical and analytic methods, we study the time dependent behavior of granular material in a vibrating box. We find, by molecular dynamics simulation, that the temporal fluctuations of the pressure and the height expansion scale in…
We find a non-invertible matrix representation for Van der Waerden's colouring theorem for two distinct colours in a one dimensional periodic lattice. Using this,an infinite one dimensional antiferromagnetic Ising system is mapped to a…
We propose very general vortex nucleation mechanisms analogous to a hydrodynamic instability and calculate associated critical velocity in agreement with experiments. The creation of vortices via extrinsic mechanism is driven by a formation…
The bosonization technique to describe correlated electrons in a one-dimensional quantum wire containing impurities is extended to include an applied voltage source. The external reservoirs are shown to lead to a boundary condition for the…
Diffusion on a T fractal lattice under the influence of topological biasing fields is studied by finite size scaling methods. This allows to avoid proliferation and singularities which would arise in a renormalization group approach on…
We have derived the expression for the specific heat by using Ginzburg-Landau (GL) theory by taking $\mid \psi \mid^{4}$ into account in the Hartree approximation. Without this term, the specific heat diverges at $T=T_{c}(B)$. It is also…
Modifying the Redfield model of sexual reproduction and the Penna model of biological aging, we compare reproduction with and without recombination in age-structured populations. In contrast to Redfield and in agreement with Bernardes we…
We present a comparison of the performance of two non-local update algorithms for path integral Monte Carlo (PIMC) simulations, the multigrid Monte Carlo method and the staging algorithm. Looking at autocorrelation times for the internal…
Theoretical model for the radiation linewidth in a multi-fluxon state of a long Josephson junction is presented. Starting from the perturbed sine-Gordon model with the temperature dependent noise term, we develop a collective coordinate…
New phenomenological approach for the description of elementary collective excitations is proposed. The crystal is considered to be an anisotropic space-time vacuum with a prescribed metric tensor in which the information on electromagnetic…
Local porosity distributions for a three-dimensional porous medium and local porosity distributions for a two-dimensional plane-section through the medium are generally different. However, for homogeneous and isotropic media having finite…
The propagator for a noninteracting many electron system in a constant magnetic field in three space time dimensions is computed. This formula and the results of [FT1,2] are used to give a microscopic derivation of a BCS-equation with…
The methods of non-equilibrium thermodynamics of systems with an interface have been applied to the study of thermionic emission processes in abrupt semiconductor junctions, including the effects of surface states . Our analysis covers…
We investigate the combined effects of electrostatic interactions and hydrodynamic interactions on the short-time rotational self-diffusion coefficient in charge-stabilized suspensions. We calculate this coefficient as a function of volume…
Arbitrarily large ground state population is a general property of any ideal bose gas when conditions of degeneracy are satisfied; it occurs at any dimension D. For $D = 1$, the condensation is diffuse, at $D = 2$ it is a sort of…
We investigate the dynamics of two-dimensional site-diluted Ising antiferromagnets. In an external magnetic field these highly disordered magnetic systems have a domain structure which consists of fractal domains with sizes on a broad range…
This is a Review of experimental observations and theoretical developments on the c-axis plasma oscillations in High-temperature superconductors.
We introduce three models of fragmentation in which the largest fragment in the system can be broken at each time step with a fixed probability, p. We solve these models exactly in the long time limit to reveal stable time invariant…
As Charles Goodyear discovered in 1839, when he first vulcanised rubber, a macromolecular liquid is transformed into a solid when a sufficient density of permanent crosslinks is introduced at random. At this continuous equi- librium phase…
The high $T_c$ cuprate superconductors doped near half-filling have short range antiferromagnetic correlations. Here we describe an intuitive local picture of why, if pairing occurs in the presence of short-range antiferromagnetic…