2020/02/29 by Lorenzo Piroli, Christoph Sünderhauf, Xiao-Liang Qi · 3 citations
Computer Science · Physics and Astronomy · #Black Holes and Theoretical Physics #Central charge #Charge (physics) #Entropy (arrow of time) #Quantum #Quantum Information and Cryptography #Quantum entanglement #Quantum many-body systems #Scrambling #Semiclassical physics #Time evolution #Unitary state #cond-mat.stat-mech #hep-th #quant-ph
paper · pdf · doi:10.1007/jhep04(2020)063
published as JHEP (2020) 2020: 63 · 23 pages, 14 figures; v2: minor revision
openalex created_date 2020/03/06 · arxiv created 2020/04/04 · openalex publication_date 2020/04/09 · arxiv updated 2020/04/14 · openalex updated_date 2026/08/05
A bstract Inspired by the Hayden-Preskill protocol for black hole evaporation, we consider the dynamics of a quantum many-body qudit system coupled to an external environment, where the time evolution is driven by the continuous limit of certain 2-local random unitary circuits. We study both cases where the unitaries are chosen with and without a conserved U(1) charge and focus on two aspects of the dynamics. First, we study analytically and numerically the growth of the entanglement entropy of the system, showing that two different time scales appear: one is intrinsic to the internal dynamics (the scrambling time), while the other depends on the system-environment coupling. In the presence of a U(1) conserved charge, we show that the entanglement follows a Page-like behavior in time: it begins to decrease in the middle stage of the “evaporation”, and decreases monotonically afterwards. Second, we study the time needed to retrieve information initially injected in the system from measurements on the environment qudits. Based on explicit numerical computations, we characterize such time both when the retriever has control over the initial configuration or not, showing that different scales appear in the two cases.