Stability of the homogeneous Bose-Einstein condensate at large gas parameter
TLDR
In this paper, the properties of the uniform Bose gas were studied within the optimized variational perturbation theory (Gaussian approximation) in a self-consistent way.Abstract:
The properties of the uniform Bose gas are studied within the optimized variational perturbation theory (Gaussian approximation) in a self-consistent way. It is shown that the atomic Bose-Einstein condensate with a repulsive interaction becomes unstable when the gas parameter $\ensuremath{\gamma}=\ensuremath{\rho}{a}^{3}$ exceeds a critical value ${\ensuremath{\gamma}}_{crit}\ensuremath{\approx}0.01$. The quantum corrections beyond the Bogoliubov-Popov approximation to the energy density, chemical potential, and pressure in powers of $\sqrt{\ensuremath{\gamma}}$ expansions are presented.read more
Citations
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High-field instability of a field-induced triplon Bose-Einstein condensate
TL;DR: In this article, the authors studied properties of magnetic field-induced Bose-Einstein condensate of triplons as a function of temperature and the field within the Hartree-Fock-Bogoliubov approach including the anomalous density.
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Quasiequilibrium Mixture of Itinerant and Localized Bose Atoms in Optical Lattice
TL;DR: In this paper, conditions under which there can exist a quasiequilibrium mixture of itinerant and localized bosonic atoms in an optical lattice, even at zero temperature and at integer filling factor, when such a coexistence is impossible for an equilibrium lattice.
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Quasi-equilibrium mixture of itinerant and localized bose atoms in optical lattice
TL;DR: In this article, conditions under which there can exist a quasi-equilibrium mixture of itinerant and localized bosonic atoms in an optical lattice, even at zero temperature and at integer filling factor, when such a coexistence is impossible for an equilibrium lattice.
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Macroscopic properties of triplon Bose-Einstein condensates
TL;DR: In this paper, the authors consider macroscopic properties of the triplon Bose-Einstein condensates in the Hartree-Fock-Bogoliubov approximation taking into account the anomalous averages and prove that these averages play the qualitative role in the condensate properties.
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Quantum phase transitions in optical lattices beyond the Bogoliubov approximation
TL;DR: In this article, a field theoretical approach in terms of path integral formalism was developed to calculate the second-order quantum corrections to the energy density as well as to the superfluid fraction in cubic optical lattices.
References
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Bose-Einstein condensation
TL;DR: The Bose-Einstein condensation (BEC) phenomenon was first introduced by Bose as discussed by the authors, who derived the Planck law for black-body radiation by treating the photons as a gas of identical particles.