Semidefinite programs at finite fermion density
Scott Lawrence · Physical review. D/Physical review. D. · 2023
Semidefinite programs can be constructed to provide a nonperturbative view of the zero-temperature behavior of quantum systems. Past work has found that small semidefinite programs (relative to the dimension of Hilbert space) yield quantitatively accurate estimates for the ground-state energy and expectation values. This paper examines the properties of these semidefinite programs when applied to lattice-regulated field theories exhibiting fermion sign problems. Specifically on the finite-density Thirring model, small semidefinite programs still yield quantitatively accurate results, and there is no indication that these methods encounter exponential costs (analogous to the fermion sign problem) at finite chemical potential.