This work presents a series of experiments with ultracold one-dimensional Bose gases, which establish said gases as an ideal model system for exploring a wide range of non-equilibrium phenomena. With the help of newly developed tools, like full distributions functions and phase correlation functions, the book reveals the emergence of thermal-like transient states, the light-cone-like emergence of thermal correlations and the observation of generalized thermodynamic ensembles. This points to a natural emergence of classical statistical properties from the microscopic unitary quantum evolution, and lays the groundwork for a universal framework of non-equilibrium physics. The thesis investigates a central question that is highly contested in quantum physics: how and to which extent does an isolated quantum many-body system relax? This question arises in many diverse areas of physics, and many of the open problems appear at vastly different energy, time and length scales, ranging from high-energy physics and cosmology to condensed matter and quantum information. A key challenge in attempting to answer this question is the scarcity of quantum many-body systems that are both well isolated from the environment and accessible for experimental study.

Auteur
Dr. Tim Langen studied physics in Mainz, Marseille, Paris and Vienna. He is currently a postdoctoral fellow at JILA, Boulder. His research interests include atomic and molecular physics, quantum optics and quantum many-body systems.

Contenu
Introduction to One-Dimensional Bose Gases.- Experimental Realization of One-Dimensional Bose Gases.- Isolated Quantum Systems out of Equilibrium.- Relaxation and Prethermalization in One-Dimensional Bose Gases.- Local Emergence of Thermal Correlations.- Experimental Observation of a Generalized Gibbs Ensemble.- Relaxation Dynamics in An Imbalanced Pair of One-Dimensional Bose Gases.- Conclusion and Outlook.