Standard lattice formulations of non-relativistic Fermi gases with two spin components suffer from a sign problem in the cases of repulsive contact interactions and attractive contact interactions
with spin imbalance. We discuss the nature of this sign problem and the applicability of stochastic quantisation with complex Langevin evolution in both cases. For repulsive interactions, we find
that the results converge, using adaptive step size scaling and a Gaussian regulator to modify the lattice action. We present results on density profiles and correlations of a harmonically trapped
system in one spatial dimension.
F. Attanasio, M. Bauer, and J. M. Pawlowski, “Density profiles and correlations of harmonically trapped ultracold fermions via complex Langevin”, PoS LATTICE2022, 363 (2023).
Related to Project C01, C02