凝聚态物理
This paper extends an earlier quantum kinetics treatment for dilute, weakly-interacting, partially Bose-Einstein condensed gases, presented by the author elsewhere [J. Res. Natl. Inst. Stand. Technol. 101, 457 (1996)], by consistently…
The two-body scattering length a for 4He atoms is much larger than their effective range r_s. As a consequence, low-energy few-body observables have universal characteristics that are independent of the interaction potential. Universality…
We study two-body correlations in systems of identical bosons. We use a Faddeev type of decomposition of the wave function where all pairs of particles are treated equally. We focus on a new multi-particle Efimov effect at large scattering…
The Pr(1-x}CaxMnO3 system exhibits a ferromagnetic insulating state for the composition range x<0.25. A metallic ferromagnetic state is never realized because of the low hole concentration and the very small averaged A-site cation radius.…
Up to now, electric field induced non-linear conduction in the Pr(1-x)CaxMnO3 system has been ascribed to a current-induced destabilization of the charge ordered phase. However, for x<0.25, a ferromagnetic insulator state is observed and…
We study the interplay of topological excitations in stripe phases: charge dislocations, charge loops, and spin vortices. In two dimensions these defects interact logarithmically on large distances. Using a renormalization-group analysis in…
Recently obtained results on linear energy bounds are generalized to arbitrary spin quantum numbers and coupling schemes. Thereby the class of so-called independent magnon states, for which the relative ground-state property can be…
We report the experimental observation of novel vortex patterns in vertically vibrated granular rods. Above a critical packing fraction, moving ordered domains of nearly vertical rods spontaneously form and coexist with horizontal rods. The…
We investigate the many-body properties of a two-dimensional electron gas constrained to the surface of a sphere, a system which is physically realized in multielectron bubbles in liquid helium. A second-quantization formalism, suited for…
We report the results of a Monte Carlo study of a model of (III,Mn)V diluted magnetic semiconductors which uses an impurity band description of carriers coupled to localized Mn spins and is applicable for carrier densities below and around…
We study the dynamics of a viscoelastic medium driven through quenched disorder by expanding about mean field theory in $6-\epsilon$ dimensions. The model exhibits a critical point separating a region where the dynamics is hysteretic with a…
From the path integral formalism for price fluctuations with non-Gaussian distributions I derive the appropriate stochastic calculus replacing Ito's calculus for stochastic fluctuations.
The analytic properties of Nilsson's Modified Oscillator (MO), which was first introduced in nuclear structure, and of the recently introduced, based on quantum algebraic techniques, 3-dimensional q-deformed harmonic oscillator (3-dim q-HO)…
We analyze, the generation of soliton-like solutions in a single-component Fermi gas of neutral atoms at zero and finite temperatures with the phase imprinting method. By using both the numerical and analytical calculations, we find the…
The effective action for the current and density is shown to satisfy an evolution equation, the functional generalization of Callan-Symanzik equation. The solution describes the dependence of the one-particle irreducible vertex functions on…
Data from an instrument that measures conductance, stiffness and rupture strength of junctions indicates that when two macroscopic metal surfaces are brought into contact a nanometer size junction spontaneously forms over a long time scale…
A force measurement technique has been developed that utilizes a clamped fiber optic element both as a cantilever and as a highly sensitive probe of the static and dynamic displacement of a sample that is mounted near its free end. Light…
Electron and phonon transient temperatures are analyzed in the case of nondegenerate semiconductors. An analytical solution is obtained for rectangular laser pulse absorption. It is shown that thermal diffusion is the main energy relaxation…
The dependence on chopper frequency of the effective thermal diffusivity and effective thermal conductivity in photoacoustic experiments is discussed. The theoretical model of a two-layer structure at rear-surface illumination in the high…
We present a model to describe the collective motion of barchan dunes in a field. Our model is able to reproduce the observation that a typical dune stays confined within a stripe. We also obtain some of the pattern structures which…