Extended study for unitary fermions on a lattice using the cumulant expansion technique
Jong-Wan Lee, Michael G. Endres, David B. Kaplan, Amy N. Nicholson
备注：
7 pages, 6 figures, Presented at 29th International Symposium on Lattice Field Theory (Lattice2011), Squaw Valley, Lake Tahoe, CA, USA, 10-16 July 2011
A recently developed lattice method for large numbers of strongly interacting nonrelativistic fermions exhibits a heavy tail in the distributions of correlators for large Euclidean time τ and large number of fermions N, which only allows the measurement of ground state energies for a limited number of fermions using standard techniques. In such cases, it is suggested that measuring the log of the correlator is more efficient, and a cumulant expansion of this quantity can be exactly related to the correlation function. The cumulant expansion technique allows us to determine the ground state energies of up to 66 unpolarized unitary fermions on lattices as large as 72$\times$14^3, and up to 70 unpolarized unitary fermions trapped in a harmonic potential on lattices as large as 72$\times$64^3. We have also improved our lattice action with a Galilean invariant form for the four-fermion interaction, which results in predictive volume scaling of the lowest energy of three fermions in a periodic box and in good agreement of our results for N \leq 6 trapped unitary fermions with those from other benchmark calculations.
A new approach for studying large numbers of fermions in the unitary regime
提出了一种新的格子方法来研究包含大量相互作用的非相对论费米子的系统。该结构非常适合于数值研究的费米子附近的么正性-一个强耦合的制度，对应于两个粒子的s波散射相移delta_0 = π/2。这样的系统可以通过实验用俘获原子实现，并为核物理的有效场论描述提供了一个起点。我们讨论我们的晶格理论的建设，这使我们能够研究系统高达（但绝不限于）38费米子具有高精度和适度的计算资源，并提供了概述的几个应用程序的技术。应用和模拟结果的更详细的讨论将在A. N. N.和J-W。L.
