Related papers: \lambda-transition in low dimensional systems with…
We present a theory describing the lambda transition and the Bose-Einstein condensation (BEC) in a liquid ${\rm ^4He}$ based on the diatomic quasiparticle concept. It is shown that in liquid ${\rm ^4He}$ for the temperature region $1~{\rm…
Quantum phase slips, i.e the primary excitations in one-dimensional superfluids at low temperature, have been well characterized in most condensed-matter systems, with the notable exception of ultracold quantum gases. Here we present our…
The realisation of Bose-Einstein condensation under grand-canonical conditions has provided the experimental evidence for the simultaneous occurrence of macroscopic fluctuations and phase coherence of the condensate. The observation of…
Within a quasiparticle framework, we reconsider the issue of computing the Bose-Einstein condensation temperature ($T_c$) in a weakly non-ideal Bose gas. The main result of this and previous investigations is that $T_c$ increases with the…
We discuss certain specific features of the calculation of the critical temperature of a dilute repulsive Bose gas. Interactions modify the critical temperature in two different ways. First, for gases in traps, temperature shifts are…
Bose-Einstein condensate shells, while occurring in ultracold systems of coexisting phases and potentially within neutron stars, have yet to be realized in isolation on Earth due to the experimental challenge of overcoming gravitational…
The Bose-Einstein condensation of a dilute gas of rubidium-87 atoms was achieved by cooling a small number of atoms in a magnetic trap. The effective potential of the trap is to lowest order harmonic and under these conditions we estimate…
The recent report of the observation of Bose-Einstein condensation in atomic Hydrogen, characterized by an "anomalous" density spectrum, is shown to be in agreement with the prediction of the existence of two condensates for temperatures…
The phenomenon of Bose-like condensation, the continuous change of the dimensionality of the particle distribution as a consequence of freezing out of one or more degrees of freedom in the low particle density limit, is investigated…
On the basis of Bethe ansatz solution of two-component bosons with SU(2) symmetry and $\delta$-function interaction in one dimension, we study the thermodynamics of the system at finite temperature by using the strategy of thermodynamic…
We consider a two-dimensional dilute Bose gas above its superfluid transition temperature. We show that the t-matrix approximation corresponds to the leading set of diagrams in the dilute limit, provided the temperature is sufficiently…
The crossover from cooperative Cooper pairing to independent bound state (composite bosons) formation and condensation in quasi-2D systems is studied. It is shown that at low carrier density the critical superconducting temperature is equal…
We have studied the properties of the scissors mode of a trapped Bose-Einstein condensate of $^{87}$Rb atoms at finite temperature. We measured a significant shift in the frequency of the mode below the hydrodynamic limit and a strong…
We discuss the phenomenon of Bose-Einstein condensation of an ideal non-relativistic Bose gas in an arbitrarily shaped cavity. The influence of the finite extension of the cavity on all thermodynamical quantities, especially on the critical…
We study the equilibrium correlations of a Bose gas in an elongated three-dimensional harmonic trap using a grand-canonical classical-field method. We focus in particular on the progressive transformation of the gas from the normal phase,…
Bose-Einstein condensation in a Bose gas is studied analytically, in any positive dimensionality ($d>0$) for identical bosons with any energy-momentum positive-exponent ($s>0$) plus an energy gap $\Delta$ between the ground state energy…
In this work we analyze a non--interacting one dimensional polymer Bose--Einstein condensate in an harmonic trap within the semiclassical approximation. We use an effective Hamiltonian coming from the polymer quantization that arises in…
We study a quantum Boltzmann-Condensation system that describes the evolution of the interaction between a well formed Bose-Einstein condensate and the quasi-particles cloud. The kinetic model is valid for a dilute regime at which the…
We consider a system of the two-parameter deformed boson oscillators whose spectrum is given by a generalized Fibonacci sequence. In order to obtain the role of the deformation parameters (q1,q2) on the thermostatistics of the system, we…
Interactions in quantum systems may induce transitions to exotic correlated phases of matter which can be vulnerable to coupling to an environment. Here, we study the stability of a Bose-Hubbard chain coupled to a bosonic bath at zero and…