Condensed Matter
We study the spontaneous emission of a partially excited Bose-Einstein condensate composed of two-level atoms. The formation of polaritons induced by the ground-state part of the condensate leads to an avoided crossing in the photon…
We solve the problem of resonance statistics in systems with broken time-reversal invariance by deriving the joint probability density of all resonances in the framework of a random matrix approach and calculating explicitly all n-point…
Floppy membranes are tensionless surfaces without extrinsic stiffness, whose fluctuations are governed by fourth-order bending elasticity. This suppresses spiky superstructures and ensures that floppy membranes remain smooth over any…
In the present paper, we analyze the consequences of scaling hypotheses on dynamic functions, as two times correlations $C(t,t')$. We show, under general conditions, that $C(t,t')$ must obey the following scaling behavior $C(t,t') =…
Numerical simulations of Ramsey fringe formation in double Bose condensates are carried out in two spatial dimensions. The effects of meanfield nonlinearity and diffusion in the condensates give rise to new features in the Ramsey fringes,…
We have studied the structure and dipole charge density response of nanorings as a function of the magnetic field using local-spin density functional theory. Two small rings consisting of 12 and 22 electrons confined by a positively charged…
We simulate late-stage coarsening of a 3D symmetric binary fluid using a lattice Boltzmann method. With reduced lengths and times l and t respectively (scales set by viscosity, density and surface tension) our data sets cover 1 < l < 10^5,…
Vortex dynamics in fermionic superfluids is carefully considered from the microscopic point of view. Finite temperatures, as well as impurities, are explicitly incorporated. To enable readers understand the physical implications,…
We report high resolution angle-scanned photoemission and Fermi surface (FS) mapping experiments on the layered transition-metal dichalcogenide 1T-TaS_2 in the quasi commensurate (QC) and the commensurate (C) charge-density-wave (CDW)…
We establish a general relation between the diagonal correlator of eigenvectors and the spectral Green's function for non-hermitian random-matrix models in the large-N limit. We apply this result to a number of non-hermitian random-matrix…
We analyze the nonlinear voltage dependence of elelctrochemical capacitance for nano-scale conductors. This voltage dependence is due to finite density of states of the conductors. We derive an exact expression for the electrochemical…
We present a general theoretical formulation, based on nonequilibrium Green's functions, for nonlinear DC transport in multi-probe mesoscopic conductors. The theory is gauge invariant and is useful for the predictions of current-voltage…
The current noise in a multi-probe mesoscopic conductor can have a nonlinear dependence on the strength of driving bias voltage. This paper presents a theoretical formulation for the nonlinear noise spectra. We pay special attention to…
Quantum tunneling was observed in the decay of metastable spin domains in gaseous Bose-Einstein condensates. A mean-field description of the tunneling was developed and compared with measurement. The tunneling rates are a sensitive probe of…
We investigate Monte Carlo energy and variance minimization techniques for optimizing many-body wave functions. Several variants of the basic techniques are studied, including limiting the variations in the weighting factors which arise in…
We consider the interaction between a Bose-Einstein condensate and a single-mode quantized light field in the presence of a strong far off-resonant pump laser. The dynamics is characterized by an exponential instability, hence the system…
We express the partition function for an equilibrium system of interacting particles in the canonical ensemble as a functional integration over the particles' density field. We outline a method to evaluate the partition function by…
It has proved difficult to extend the density matrix renormalization group technique to large two-dimensional systems. In this Communication I present a novel approach where the calculation is done directly in two dimensions. This makes it…
The full-potential linearized augmented-plane wave (FP-LAPW) method is well known to enable most accurate calculations of the electronic structure and magnetic properties of crystals and surfaces. The implementation of atomic forces has…
Based on the Majumdar-Ghosh chain we construct several spin models which allow us to investigate spinon dynamics in the regime close to deconfinement of spinons. We consider the J_1 - J_2 - \delta model, two coupled J_1 - J_2 chains…