From non-hermitian linear response to dynamical correlations and fluctuation-dissipation relations in quantum many-body systems

• Verfasst von: Geier, Kevin [VerfasserIn]
• Verfasst von: Hauke, Philipp [VerfasserIn]
• Titel: From non-hermitian linear response to dynamical correlations and fluctuation-dissipation relations in quantum many-body systems
• Verf.angabe: Kevin T. Geier and Philipp Hauke
• E-Jahr: 2022
• Jahr: 15 July 2022
• Umfang: 34 S.
• Fussnoten: Gesehen am 05.12.20ww
• Titel Quelle: Enthalten in: PRX quantum
• Ort Quelle: College Park, MD : American Physical Society, 2020
• Jahr Quelle: 2022
• Band/Heft Quelle: 3(2022), 3, Artikel-ID 030308, Seite 1-34
• ISSN Quelle: 2691-3399
• DOI: doi:10.1103/PRXQuantum.3.030308
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1824439199

Abstract

Quantum many-body systems are characterized by their correlations. While equal-time correlators and unequal-time commutators between operators are standard observables, the direct access to unequal-time anticommutators poses a formidable experimental challenge. Here, we propose a general technique for measuring unequal-time anticommutators using the linear response of a system to a non-Hermitian perturbation. We illustrate the protocol at the example of a Bose-Hubbard model, where the approach to thermal equilibrium in a closed quantum system can be tracked by measuring both sides of the fluctuation-dissipation relation. We relate the scheme to the quantum Zeno effect and weak measurements, and illustrate possible implementations at the example of a cold-atom system. Our proposal provides a way of characterizing dynamical correlations in quantum many-body systems with potential applications in understanding strongly correlated matter as well as for novel quantum technologies.