论文标题
耦合群集理论的有吸引力的费米气体的正常状态
The normal state of attractive Fermi gases from coupled-cluster theory
论文作者
论文摘要
我们介绍了耦合群集（CC）理论，用于对两种组分的正常状态的数值研究，稀释了在零温度下具有有吸引力的短距离相互作用的费米气体。我们专注于具有双重激发（CCD）的CC理论，并讨论了其与T-Matrix近似（即通过随机相近似的梯形图重新召集）的密切关系。我们进一步讨论了它与雪佛兰（Chevy）在费米极化（Fermi Polaron）上的变异波函数ANSATZ的关系，并认为CCD是其自然扩展到非零少数族裔浓度。研究正常状态能量学对于一系列相互作用强度以下和更高，我们发现CCD与固定节点扩散蒙特卡洛产生了良好的一致性。我们发现CCD不会收敛于小极化和较大的相互作用强度，我们推测这将其归因于新生的不稳定性。
We introduce coupled-cluster (CC) theory for the numerical study of the normal state of two-component, dilute Fermi gases with attractive, short-range interactions at zero temperature. We focus on CC theory with double excitations (CCD) and discuss its close relationship with -- and improvement upon -- the t-matrix approximation, i.e., the resummation of ladder diagrams via a random-phase approximation. We further discuss its relationship with Chevy's variational wavefunction ansatz for the Fermi polaron and argue that CCD is its natural extension to nonzero minority species concentrations. Studying normal state energetics for a range of interaction strengths below and above unitarity, we find that CCD yields good agreement with fixed-node diffusion Monte Carlo. We find that CCD does not converge for small polarizations and large interaction strengths, which we speculatively attribute to the nascent instability to a superfluid state.
