Efficient algorithms for weakly interacting quantum spin systems
Phys. Rev. A 114, 012432 – Published 13 July, 2026
DOI: https://doi.org/10.1103/45rz-42gr
Abstract
We establish efficient algorithms for weakly interacting quantum spin systems at arbitrary temperature. In particular, we obtain a fully polynomial-time approximation scheme for the partition function and an efficient approximate sampling scheme for the thermal distribution over a classical spin space. Our approach is based on the cluster expansion method and a standard reduction from approximate sampling to approximate counting.
