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论文类型：期刊论文

发表时间：2014-03-11

发表刊物：PHYSICAL REVIEW A

收录刊物：SCIE、EI、Scopus

卷号：89

期号：3

ISSN号：1050-2947

摘要：We derive the expressions for the virial coefficients up to the third order for two-species fermion mixtures, and investigate the fugacity of the species and the interaction energy density around the s-wave Feshbach resonance in Li-6-K-40 mixtures. The theoretical results show that the magnitude of the virial coefficients depends on the mass ratio in a mass-imbalanced system. We find that the contribution of two-body bound states to high-order virial coefficients is very small at temperatures of microkelvin order. With the decrease of T / T-F, the positions of the maxima of fugacity and interaction energy density shift away from the resonance position in the third-order virial expansion calculation. The mass ratio determines the relevance between the fugacity and number density of heavy species. Our conclusion is also effective for other mass-imbalanced systems.