Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2012 Dec 14;109(24):240401. doi: 10.1103/PhysRevLett.109.240401. Epub 2012 Dec 10.
A three-component Fermi gas near a broad Feshbach resonance does not have a universal ground state due to the Thomas collapse, while it does near a narrow Feshbach resonance. We explore its universal phase diagram in the plane of the inverse scattering length 1/ak(F) and the resonance range R()k(F). For a large R()k(F), there exists a Lifshitz transition between superfluids with and without an unpaired Fermi surface as a function of 1/ak(F). With decreasing R(*)k(F), the Fermi surface coexisting with the superfluid can change smoothly from that of atoms to trimers ("atom-trimer continuity"), corresponding to the quark-hadron continuity in a dense nuclear matter. Eventually, there appears a finite window in 1/ak(F) where the superfluid is completely depleted by the trimer Fermi gas, which gives rise to a pair of quantum critical points. The boundaries of these three quantum phases are determined in regions where controlled analyses are possible and are also evaluated based on a mean-field plus trimer model.
在宽的费什巴赫共振附近的三组分费米气体由于托马斯坍塌而没有通用基态，而在窄的费什巴赫共振附近则有通用基态。我们在倒散射长度 1/ak(F)和共振范围 R()k(F)的平面上探索其通用相图。对于大的 R()k(F)，随着 1/ak(F)的变化，存在带和不带未配对费米表面的超流之间的 Lifshitz 转变。随着 R(*)k(F)的减小，与超流共存的费米表面可以从原子平滑地转变为三聚体（“原子-三聚体连续性”），对应于稠密核物质中的夸克-强子连续性。最终，在 1/ak(F)的有限窗口中，超流完全被三聚体费米气体耗尽，这导致一对量子临界点的出现。这三个量子相的边界在可以进行受控分析的区域中确定，并基于平均场加三聚体模型进行评估。
