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 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.
@article{arxiv.2509.01637,
title = {Phase-Sensitive Measurements on a Fermi-Hubbard Quantum Processor},
author = {Alberto R. Cavallar and Luis Escalera-Moreno and Titus Franz and Timon Hilker and J. Ignacio Cirac and Philipp M. Preiss and Benjamin F. Schiffer},
journal= {arXiv preprint arXiv:2509.01637},
year = {2026}
}
Comments
10+7 pages, 5+6 figures, final version accepted for publication in Quantum