Year: 2020
Type: dissertation
Abstract: Bridging the gap between macroscopic thermodynamics and microscopic quantum dynamics is one of the most fundamental problems in statistical physics, dating back to von Neumann.Recently, nonequilibrium dynamics of isolated quantum many-body systems have been observed in highly controllable quantum systems, such as ultracold atoms, superconducting qubits, and trapped ions.Both theoretical and experimental studies have revealed that isolated manybody systems thermalize under the unitary time evolution.These studies triggered progress in understanding mechanisms of thermalization.A widely accepted mechanism of thermalization is based on a conjecture called the eigenstate thermalization hypothesis (ETH).The ETH is a counterpart of ergodicity in quantum systems and states that all the energy eigenstates of a chaotic Hamiltonian are indistinguishable from the thermal states.The ETH has been numerically confirmed for many nonintegrable systems, while it is violated in integrable systems and localized systems.Another essential concept of thermodynamics is the second law, which is formulated in several ways, such as the entropy increase and the impossibility of the perpetual motion of the second kind.The second law in quantum systems has been studied based on quantum * 1 The Srednicki's ansatz (2.29) is not a mathematically rigorous statement, because the left-hand side of Eq. (2.29) is not a stochastic variable, while the right-hand side is a stochastic variable.
DOI: 10.15083/0002004841
Author: KANEKO, KAZUYA
Institution: The University of Tokyo
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Award: 量子情報理論を用いた孤立量子系の熱力学第二法則の構築
OpenAlex ID: W7207701550