Quantum dynamics of non-perturbative solutions

Kovtun, Andrei (2022): Quantum dynamics of non-perturbative solutions. Dissertation, LMU München: Fakultät für Physik

Abstract

The goal of this work is to study a recently introduced phenomenon called quantum breaking. This phenomenon stands for the destruction of the overall macroscopic dynamics of the semi-classical system due to the quantum effects, and is expressed in the capturing the difference between the classical evolution, and its true (or full) quantum evolution. Here, I would like to address several points. The first and foremost, is to introduce a unified formalism for computing approximate quantum evolution to capture non-trivial dynamical effects. It seems to be essential to do that, because all the approaches considered in the literature so far were subjected to peculiar features of the systems under consideration, and were different from one another. So, it is always handy to have an approach allowing for broad applicability. This approach manages two problems: the method of computation of the evolution, and the general criterion to identify timescale associated with quantum breaking. The second goal, is to actually simulate quantum evolution and detect quantum breaking for several relativistic systems emerging in the theory of the complex scalar field, and compare these results to the ones already obtained in previous research. The systems that are considered here are stable and unstable Bose-Einstein condensates emerging in the complex scalar field theory. The evolution was computed in both cases by using two-particle irreducible effective action equipped with "in-in" integration contour. Timescales of the quantum breaking were identified on the basis of the newly introduced criterion, and compared to those obtained in literature already.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: Quantum Field Theory, Quantum Breaking, Bose-Einstein Condensate, Non-perturbative Quantum Field Theory, 2PI Effective Action
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 530 Physik
• Fakultäten: Fakultät für Physik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 12. Dezember 2022
• 1. Bericht­erstatter:in: Dvali, Gia