2019/08/31 by Dana Faiez, Dominik Šafránek, J. M. Deutsch +1
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Physics #Quantum #Quantum Information and Cryptography #Quantum many-body systems #Quantum mechanics #cond-mat.quant-gas #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1103/physreva.101.052101
published as Phys. Rev. A 101, 052101 (2020) · Additional comments are made in the caption of figure 10 (a). Equation 7 and a brief description are added in relation to figure 4
openalex publication_date 2020/05/04 · arxiv created 2020/05/28 · arxiv updated 2020/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In this paper, we investigate and compare two well-developed definitions of entropy relevant for describing the dynamics of isolated quantum systems: bipartite entanglement entropy and observational entropy. In a model system of interacting particles in a one-dimensional lattice, we numerically solve for the full quantum behavior of the system. We characterize the fluctuations and find the maximal, minimal, and typical entropy of each type that the system can eventually attain through its evolution. While both entropies are low for some particular configurations and high for more generic ones, there are several fundamental differences in their behavior. Observational entropy behaves in accord with classical Boltzmann entropy (e.g., equilibrium is a condition of near-maximal entropy and uniformly distributed particles, and minimal entropy is a very compact configuration). Entanglement entropy is rather different: Minimal entropy ``empties out'' one partition while maximal entropy apportions the particles between the partitions, and neither is typical. Beyond these qualitative results, we characterize both entropies and their fluctuations in some detail as they depend on temperature, particle number, and box size.