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  "path": "/papers/q-2026-05-12-2103/",
  "publishedAt": "2026-05-12T14:01:08.000Z",
  "site": "https://quantum-journal.org",
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    "https://doi.org/10.22331/q-2026-05-12-2103"
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  "textContent": "Quantum 10, 2103 (2026).\n\nhttps://doi.org/10.22331/q-2026-05-12-2103\n\nFermionic 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.",
  "title": "Phase-Sensitive Measurements on a Fermi–Hubbard Quantum Processor"
}