SAIFR:4517

Emergence of Fermi's Golden Rule

(2024). Emergence of Fermi's Golden Rule. ICTP South American Institute for Fundamental Research. https://scivideos.org/ictp-saifr/4517

Emergence of Fermi's Golden Rule. ICTP South American Institute for Fundamental Research, Aug. 21, 2024, https://scivideos.org/ictp-saifr/4517 

          @misc{ scivideos_SAIFR:4517,
            doi = {},
            url = {https://scivideos.org/ictp-saifr/4517},
            author = {},
            keywords = {ICTP-SAIFR, IFT, UNESP},
            language = {en},
            title = {Emergence of Fermi{\textquoteright}s Golden Rule},
            publisher = { ICTP South American Institute for Fundamental Research},
            year = {2024},
            month = {aug},
            note = {SAIFR:4517 see, \url{https://scivideos.org/ictp-saifr/4517}}
          }
Tobias Micklitz
Talk numberSAIFR:4517
Source RepositoryICTP – SAIFR
Collection
Talk Type Conference
Subject

Abstract

Fermi's Golden Rule (FGR) applies in the limit where an initial quantum state is weakly coupled to a continuum of other final states overlapping its energy. In this seminar I will discuss what happens away from this limit, where the set of final states is discrete, with a nonzero mean level spacing. This question arises, for example, in the context of thermalization of closed many-body quantum systems when the many body localized phase becomes unstable to avalanches. After a brief motivation, I will discuss for different symmetry classes, the universal crossovers in the average decay of the initial state as the level spacing is varied, with the Golden Rule emerging in the limit of a continuum. Among the corrections to the exponential decay of the initial state given by FGR is the appearance of the spectral form factor in the long-time regime for small but nonzero level spacing.