Lee-Yang theorem for fermions
quant-ph, cond-mat.stat-mech, cond-mat.str-el, cs.CC, math-ph, math.MP
Submitted: 2026-09-20
Updated: 2026-09-20
Comments: 16 pages
License: http://creativecommons.org/licenses/by/4.0/
The gist: Lee-Yang theorems are a powerful tool for studying many-body systems, with applications ranging from analyzing phase transitions to proving the efficiency of certain classical and quantum algorithms.
Terminology
Abstract
Lee-Yang theorems are a powerful tool for studying many-body systems, with applications ranging from analyzing phase transitions to proving the efficiency of certain classical and quantum algorithms. In this work, we prove a Lee-Yang zero-freeness theorem for the partition function of a broad class of interacting fermion models, implying the existence of a provably efficient quantum algorithm for estimating their ground-state energies. This class includes several well-known models such as the attractive Hubbard model, repulsive Hubbard model on bipartite graphs, and the interacting Hofstadter model. Our results also rigorously establish the nonexistence of phase transitions in these models in the presence of a nonzero local external field.
Sources
- The Complexity of Stoquastic Local Hamiltonian Problems
- Efficient quantum algorithm for Heisenberg spin systems
- Spectral gap of Lee-Yang Hamiltonians
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