Molecular Bose-Einstein condensation in a Bose gas with a wide Feshbach resonance at finite temperatures

Abstract

Bose-Einstein condensation (BEC) of Feshbach molecules in a homogeneous Bose gas is studied at finite temperatures in a single-channel mean-field approach where the Hartree-Fock energy and pairing gap are determined self-consistently. In the molecular-BEC state, the atomic excitation is gapped and the molecular excitation is gapless. The binding energy of Feshbach molecules is shifted from the vacuum value due to many-body effect. When the scattering length $a_s$ of atoms is negative, the system is subject to mechanical collapse due to negative compressibility. The system is stable in most regions with positive scattering lengths. However at low temperatures near the resonance, the molecular-BEC state vanishes, and the coherent mixture of atomic and molecular BEC is subject to mechanical collapse.

13 pages, 4 figures

References in corpus (5)

• Formation of Quantum-Degenerate Sodium Molecules
• Evidence for Universal Four-Body States Tied to an Efimov Trimer
• Broad versus narrow Fano-Feshbach resonances in the BCS-BEC crossover with trapped Fermi atom
• Phase diagram of a Bose gas near a wide Feshbach resonance
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Cited by in corpus (2)

• Critical temperature of pair condensation in a dilute Bose gas with spin-orbit coupling
• Bardeen-Cooper-Schrieffer--type pairing in a spin-$\frac{1}{2}$ Bose gas with spin-orbit coupling