Phase-sensitive measurements on a Fermi-Hubbard quantum processor

Fermionic quantum processors are a promising platform for quantum simulation of correlated fermionic matter. In this work, we study a hardware-efficient protocol for measuring complex expectation values of the time-evolution operator, commonly referred to as Loschmidt echoes, with fermions in an optical superlattice. We analyze the algorithm for the Fermi–Hubbard model at half-filling as well as at finite doping. The method relies on global quench dynamics and short imaginary time evolution, the latter being realized by architecture-tailored pulse sequences starting from a product state of plaquettes. Our numerical results show that complex-valued Loschmidt echoes can be efficiently obtained for large many-body states over a broad spectral range. This allows one to measure spectral properties of the Fermi–Hubbard model, such as the local density of states, and paves the way for the study of finite-temperature properties in current fermionic quantum simulators.

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539: Matter; Molecular Physics; Atomic and Nuclear physics; Radiation; Quantum Physics

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https://creativecommons.org/licenses/by/4.0/

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publishedVersion

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q-2026-05-12-2103.pdf

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4.25 MB

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Phase-sensitive measurements on a Fermi-Hubbard quantum processor