2018/09/18 by Simon A. Weidinger, Simon Weidinger, Sarang Gopalakrishnan +1 · 37 citations
Physics and Astronomy · #Condensed matter physics #Hartree–Fock method #Non-equilibrium thermodynamics #Phenomenology (philosophy) #Physics #Physics of Superconductivity and Magnetism #Quantum #Quantum and electron transport phenomena #Quantum many-body systems #Quantum mechanics #Quasiperiodic function #Relaxation (psychology) #Statistical physics #cond-mat.dis-nn
paper · pdf · doi:10.1103/physrevb.98.224205
published in Physical review. B./Physical review. B 98(22) (American Physical Society) · 11 pages, 10 figures, Added references and expanded discussions
arxiv created 2018/09/18 · openalex publication_date 2018/12/26 · arxiv updated 2018/12/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
In this paper, we develop a self-consistent Hartree-Fock approach to theoretically study the far-from-equilibrium quantum dynamics of interacting fermions, and apply this approach to explore the onset of many-body localization (MBL) in these systems. We investigate the dynamics of a state with a nonequilibrium density profile; we find that at weak disorder the density profile equilibrates rapidly, whereas for strong disorder it remains frozen on the accessible timescales. We analyze this behavior in terms of the Hartree-Fock self-energy. At weak disorder, the self-energy fluctuates strongly and can be interpreted as a self-consistent noise process. By contrast, at strong disorder the self-energy evolves with a few coherent oscillations which cannot delocalize the system. Accordingly, the nonequilibrium site-resolved spectral function shows a broad spectrum at weak disorder and sharp spikes at strong disorder. Our Hartree-Fock theory incorporates spatial fluctuations and rare-region effects. As a consequence, we find subdiffusive relaxation in random systems; but, when the system is subjected to weak quasiperiodic potentials, the subdiffusive response ceases to exist, as rare region effects are absent in this case. This self-consistent Hartree-Fock approach can be regarded as a relatively simple theory that captures much of the MBL phenomenology.