We use a two-channel model to investigate an interacting Bose gas across a narrow Feshbach resonance within a field path integral approach. The ground-state properties show strong deviation from that of a broad Feshbach resonance or a single-channel interaction. The deviation can be interpreted by the strong energy dependence of two-body scattering length near a narrow Feshbach resonance. As the density increases, the chemical potential and energy per particle are found to saturate while the inverse compressibility and the phonon velocity undergo a significant reduction. We also take Gaussian fluctuations into account and calculate the ground-state energy correction as well as the quantum depletion.We use a two-channel model to investigate an interacting Bose gas across a narrow Feshbach resonance within a field path integral approach. The ground-state properties show strong deviation from that of a broad Feshbach resonance or a single-channel interaction. The deviation can be interpreted by the strong energy dependence of two-body scattering length near a narrow Feshbach resonance. As the density increases, the chemical potential and energy per particle are found to saturate while the inverse compressibility and the phonon velocity undergo a significant reduction. We also take Gaussian fluctuations into account and calculate the ground-state energy correction as well as the quantum depletion.

arXiv:2004.00936Physical Review AJun 3, 20240 citations

Density Fluctuations in Ultracold One-dimensional Bose Gases

Nick P. Proukakis

May 2, 20051 citation

Feshbach resonances in a strictly two-dimensional atomic Bose gas

Kalai Kumar Rajagopal, Patrizia Vignolo, Monica Tosi

arXiv:cond-mat/0503700Physica B Condensed MatterOct 13, 20045 citations

Quantum phase transition in a 2D atomic Bose gas with a g-wave Feshbach resonance

Zhang, Fan, Yin, Lan

Recent repoet on the formation of two-dimensional Bose-Einstein condensates (BECs) of spinning g-wave molecules is surprise. Here we study quantum phase transition in the quasi-2D atomic Bose gas with a g-wave Feshbach resonance, and show that there are two phase transitions in this system: from a phase with only a atomic Bose-Einstein condensate to a phase with coexistence of atomic and molecular condensation and from the coexistence phase to a phase with only a molecular Bose-Einstein condensate. We show that the g-wave resonance Feshbach has two features in the phase transitions, a phase with only a atomic Bose-Einstein condensate is no longer forbidden and resonance effects appear only at levels beyond the mean-field. We determine the T=0 beyond mean-field phase diagram of the gas as a function of magnetic field and molecular condensation density. We also detemine the ratio of atomic to molecular condensation in the coexistence phase, which can be tested in experiments.Recent repoet on the formation of two-dimensional Bose-Einstein condensates (BECs) of spinning g-wave molecules is surprise. Here we study quantum phase transition in the quasi-2D atomic Bose gas with a g-wave Feshbach resonance, and show that there are two phase transitions in this system: from a phase with only a atomic Bose-Einstein condensate to a phase with coexistence of atomic and molecular condensation and from the coexistence phase to a phase with only a molecular Bose-Einstein condensate. We show that the g-wave resonance Feshbach has two features in the phase transitions, a phase with only a atomic Bose-Einstein condensate is no longer forbidden and resonance effects appear only at levels beyond the mean-field. We determine the T=0 beyond mean-field phase diagram of the gas as a function of magnetic field and molecular condensation density. We also detemine the ratio of atomic to molecular condensation in the coexistence phase, which can be tested in experiments.

arXiv:2505.19070May 25, 20250 citations

Properties of a dilute Bose gas near a Feshbach resonance

Lan Yin, Zhenhua Ning

In this paper, properties of a homogeneous Bose gas with a Feshbach resonance are studied in the dilute region at zero temperature. The stationary state contains condensations of atoms and molecules. The ratio of the molecule density to the atom density is $\ensuremath{\pi}{\mathrm{na}}^{3}.$ There are two types of excitations, molecular excitations and atomic excitations. Atomic excitations are gapless, consistent with the traditional theory of a dilute Bose gas. The molecular excitation energy is finite in the long-wavelength limit as observed in recent experiments on ${}^{85}\mathrm{Rb}.$ In addition, the decay process of the condensate is studied. The coefficient of the three-body recombination rate is about 140 times larger than that of a Bose gas without a Feshbach resonance, in reasonably good agreement with the experiment on ${}^{23}\mathrm{Na}.$ In this paper, properties of a homogeneous Bose gas with a Feshbach resonance are studied in the dilute region at zero temperature. The stationary state contains condensations of atoms and molecules. The ratio of the molecule density to the atom density is $\ensuremath{\pi}{\mathrm{na}}^{3}.$ There are two types of excitations, molecular excitations and atomic excitations. Atomic excitations are gapless, consistent with the traditional theory of a dilute Bose gas. The molecular excitation energy is finite in the long-wavelength limit as observed in recent experiments on ${}^{85}\mathrm{Rb}.$ In addition, the decay process of the condensate is studied. The coefficient of the three-body recombination rate is about 140 times larger than that of a Bose gas without a Feshbach resonance, in reasonably good agreement with the experiment on ${}^{23}\mathrm{Na}.$

arXiv:cond-mat/0304548Physical Review ASep 19, 20038 citations

{}^{85}\mathrm{Rb}.

In addition, the decay process of the condensate is studied. The coefficient of the three-body recombination rate is about 140 times larger than that of a Bose gas without a Feshbach resonance, in reasonably good agreement with the experiment on

{}^{23}\mathrm{Na}.