Phase-sensitive measurements on a Fermi–Hubbard quantum processor

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Cavallar, Alberto R. and Escalera-Moreno, Luis and Franz, Titus and Hilker, Timon and Cirac, J. Ignacio and Preiss, Philipp M. and Schiffer, Benjamin F. (2026) Phase-sensitive measurements on a Fermi–Hubbard quantum processor. Quantum, 10. 2103. ISSN 2521-327X (https://doi.org/10.22331/q-2026-05-12-2103)

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Abstract

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.

ORCID iDs

Cavallar, Alberto R., Escalera-Moreno, Luis, Franz, Titus, Hilker, Timon ORCID logoORCID: https://orcid.org/0000-0002-1012-5750, Cirac, J. Ignacio, Preiss, Philipp M. and Schiffer, Benjamin F.;
  • Item type:Article
    ID code:96319
    Dates:
    Date
    Event
    12 May 2026
    Published
    18 April 2026
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:21 May 2026 08:42
    Last modified:04 Jun 2026 07:40
    URI:https://strathprints.strath.ac.uk/id/eprint/96319
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