凝聚态物理
A systematic analysis of the Burgers--Kardar--Parisi--Zhang equation in $d+1$ dimensions by dynamic renormalization group theory is described. The fixed points and exponents are calculated to two--loop order. We use the dimensional…
We give an account of matter and (basically) a solution of a new class of problems synthesizing percolation theory and branching diffusion processes. They led us to realizing a novel type of stochastic processes, namely branching processes…
Columnar defects provide effective pinning centers for magnetic flux lines in high--$T_{\rm c}$ superconductors. Utilizing a mapping of the statistical mechanics of directed lines to the quantum mechanics of two--dimensional bosons, one…
This paper reports conduction mechanism in a-\sbse over a wide range of temperature (238K to 338K) and frequency (5Hz to 100kHz). The d.c. conductivity measured as a function of temperature shows semiconducting behaviour with activation…
We derive an effective topological field theory model of the four dimensional quantum Hall liquid state recently constructed by Zhang and Hu. Using a generalization of the flux attachment transformation, the effective field theory can be…
Magnetic relaxation and frequency response were measured in frozen ferrimagnetic colloids of different concentrations. A crossover from reversible to irreversible behavior is observed for concentrated colloids. In irreversible state,…
We discuss observations of the ion flux from a cloud of trapped metastable helium atoms. Both Bose-Einstein condensates and thermal clouds were investigated. The ion flux is compared to time-of-flight observations of the expanded cloud. We…
We calculate a grand partition function of the attractive Bose gas in the infinite space within some approximations. Using the idea of the Yang-Lee zeros, it is proved that the gas-liquid condensation occurs before the conventional…
One-dimensional reaction-diffusion models A+A -> 0, A+A -> A, and $A+B -> 0, where in the latter case like particles coagulate on encounters and move as clusters, are solved exactly with anisotropic hopping rates and assuming synchronous…
We analyze the influence of spatial orientation on the optical response of hydrogenated silicon quantum wires. The results are relevant for the interpretation of the optical properties of light emitting porous silicon. We study…
We use Clebsch potentials and an action principle to derive a closed system of gauge invariant equations for sound superposed on a general background flow. Our system reduces to the Unruh (1981) and Pierce (1990) wave equations when the…
Realization of a robust nanotube-heterostructure tunneling transistors [Solid State Comm. 116, p. 569 (2000)] requires the difficult formation [Science 293, p. 76 (2001)] of a central nanoscale barrier separating a pair of outside metallic…
We point out a possible mechanism by which smooth surfaces can become spiky as the constant of curvature stiffness $\kappa$ falls below certain critical values. This happens either in a single first-order transition, or in a sequence of two…
We introduce a generalization of the O(N) field theory to N-colored membranes of arbitrary inner dimension D. The O(N) model is obtained for D->1, while N->0 leads to self-avoiding tethered membranes (as the O(N) model reduces to…
The spin-spin correlation function of the spherical model being precisely at an anisotropic Lifshitz point of arbitrary order is calculated exactly. The results are in agreement with scaling. The scaling function is shown to be universal.…
In honor of Onsager's ninetieth birthday, we like to review some exact results obtained so far in the chiral Potts models and to translate these results into language more transparent to physicists, so that experts in Monte Carlo…
The effective potential of scalar QED is computed analytically up to two loops in the Landau gauge. The result is given in 4-epsilon dimensions using minimal subtraction and epsilon-expansions. In three dimensions, our calculation is…
We examine the anyon representation of the Laughlin quasi-holes, in particular the one-dimensional, algebraic aspects of the representation. For the cases of one and two quasi-holes an explicit mapping to anyon systems is given, and the…
This paper has been withdrawn by the authors due to substantial changes.
We discuss the Fermion sign problem and, by examining a very general Hubbard-Stratonovich (HS) transformation, argue that the sign problem cannot be solved with such methods. We propose a different kind of transformation which, while not…