Related papers: Green-function method in the theory of ultraslow e…
This paper studies theoretically the ultraslow light phenomenon in Bose-Einstein condensates of alkali-metal atoms. The description is based on the linear approach that is developed in the framework of the Green function formalism. It is…
The response of the system, consisting of two kinds of opposite-charged fermions and their bound states (hydrogen-like atoms), to the perturbation by the external electromagnetic field in low particle kinetic energies region is studied.…
We study the temperature dependence of optical properties of dilute gases of alkali-metal atoms in the state with Bose-Einstein condensates. The description is constructed in the framework of the microscopic approach that is based on the…
We develop a microscopic approach to the consistent construction of the kinetic theory of dilute weakly ionized gases of hydrogen-like atoms. The approach is based on the framework of the second quantization method in the presence of bound…
We discuss the transport of a tracer particle through the Bose Einstein condensate of a Bose gas. The particle interacts with the atoms in the Bose gas through two-body interactions. In the limiting regime where the particle is very heavy…
We represent a new microscopic approach that allows studying the propagation properties of microwaves in a Bose-Einstein condensate of alkali atoms. It is assumed that the frequency of signal is tuned up to the transition between hyperfine…
The burgeoning field of Bose-Einstein condensation in dilute alkali and hydrogen gases has stimulated a great deal of research into the statistical physics of weakly interacting quantum degenerate systems. The recent experiments offer the…
Single particle states in the atomic trap employing the rotating magnetic field are found using the full time-dependent instantaneous trapping potential. These states are compared with those of the effective time-averaged potential. We show…
We review and extend the theory of the dynamics of Bose-Einstein condensation in weakly interacting atomic gases. We present in a unified way both the semiclassical theory as well as the full quantum theory. This is achieved by deriving a…
We examine the possibility of Bose-Einstein condensation in one-dimensional interacting Bose gas subjected to confining potentials of the form $V_{\rm ext}(x)=V_0(|x|/a)^\gamma$, in which $\gamma < 2$, by solving the Gross-Pitaevskii…
We study a many-body system of interacting fermionic atoms of two species that are in thermodynamic equilibrium with their condensed heteronuclear bound states (molecules). In order to describe such an equilibrium state, we use a…
The dielectric formalism is used to set up an approximate description of a spatially homogeneous weakly interacting Bose gas in the collision-less regime, which is both conserving and gap-less, and has coinciding poles of the…
We diagonalize the second-quantized Hamiltonian of a one-dimensional Bose gas with a nonpoint repulsive interatomic potential and zero boundary conditions. At weak coupling the solutions for the ground-state energy $E_{0}$ and the…
This paper deals with the study of the behaviour of the wave functions of a two-component Bose-Einstein condensate in the case of weak segregation. This amounts to the study of the asymptotic behaviour of a heteroclinic connection in a…
Quantum field theory of equilibrium and nonequilibrium Bose-Einstein condensates is formulated so as to satisfy three basic requirements: the Hugenholtz-Pines relation; conservation laws; identities among vertices originating from…
At finite temperatures below the phase transition point, the Bose-Einstein condensation, the macroscopic occupation of a single quantum state by particles of integer spin, is not complete. In the language of superfluid helium, this means…
We present a microscopic theory of the second order phase transition in an interacting Bose gas that allows one to describe formation of an ordered condensate phase from a disordered phase across an entire critical region continuously. We…
We apply a path integral variational approach to obtain analytical expressions for condensate wave functions of an ultracold, interacting trapped Bose gases. As in many recent experiments, the particles are confined in a 1D or 3D harmonic…
We derive Ward-Takahashi identities for correlated Bose-Einstein condensates based on the expressions of the first-order variations $(\delta\Psi,\delta G)$ due to perturbations obtained in the preceding paper [T. Kita, J. Phys. Soc. Jpn.…
These notes present simple theoretical approaches to study Bose-Einstein condensation in trapped atomic gases and their comparison to recent experimental results : - the ideal Bose gas model - Fermi pseudopotential to model the atomic…