Impact of quantum coherence on the dynamics and thermodynamics of quenched free fermions coupled to a localized defect

Year: 2026

Authors: Donelli B., De Chiara G., Scazza F., Gherardini S.

Autors Affiliation: Ist Nazl Ott Consiglio Nazl Ric CNR INO, Largo Enr Fermi 6, I-50125 Florence, Italy; Univ Firenze, European Lab Nonlinear Spect, I-50019 Sesto Fiorentino, Italy; Univ Autonoma Barcelona, Dept Fis, Fis Teor Informacio & Fenomens Quant, Bellaterra 08193, Spain; Queens Univ Belfast, Ctr Quantum Mat & Technol, Sch Math & Phys, Belfast BT7 1NN, North Ireland; Univ Trieste, Dept Phys, I-34127 Trieste, Italy; Ist Nazl Ott Consiglio Nazl Ric CNR INO, I-34149 Trieste, Italy.

Abstract: We investigate the nonequilibrium quantum dynamics and thermodynamics of free fermions suddenly coupled to a localized defect in a one-dimensional harmonic trap. This setup realizes a quantum quench transformation that gives rise to the orthogonalization of the system’s wave function as an effect of the localized perturbation. Using the Loschmidt echo and the Kirkwood-Dirac quasiprobability (KDQ) distribution of the work done by the defect, we quantify the extent and rate of the orthogonalization dynamics. In particular, we show that initializing the system in a coherent superpositions of energy eigenstates leads to nonclassical features, such as Wigner function’s negativity and nonpositivity of the work KDQ distribution. Starting from simple single-particle superpositions and then progressing with coherent and cat states of few-body fermionic systems, we uncover how quantum coherence and few-body correlations shape the out-of-equilibrium response due to the presence of the defect.

Journal/Review: PHYSICAL REVIEW A

Volume: 113 (1)      Pages from: 13311-1  to: 13311-18

More Information: B.D., F.S., and S.G. acknowledge financial support from the PNRR MUR Project No. PE0000023-NQSTI funded by the European Union-Next Generation EU. G.D.C. and S.G. acknowledge support from the Royal Society Project IESR3223086 Dissipation-based quantum inference for out-of-equilibrium quantum many-body systems. F.S. acknowledges financial support from the European Union under the Horizon 2020 research and innovation program (Project OrbiDynaMIQs, GA No. 949438) . This publication has also received funding under the Horizon Europe HORIZON-CL4-2022-QUANTUM-02-SGA program (Project PASQuanS2.1, GA No. 101113690) .
KeyWords: Metals; Gases
DOI: 10.1103/5kt1-5m83