Non-equilibrium Dynamics of Tunnel-Coupled Superfluids: Relaxation to a Phase-Locked Equilibrium State in a One-Dimensional Bosonic Josephson Junction

The experimental study of a relaxation phenomenon in a one-dimensional bosonic Josephson junction is presented, where a large spatial separation and a tilt of the double-well potential enable the preparation of initial states. Tunneling dynamics exhibit a relaxation to a phase-locked equilibrium state, contradicting theoretical predictions.

Format: Paperback / softback
Length: 187 pages
Publication date: 29 August 2021
Publisher: Springer Nature Switzerland AG

The study of the relaxation of isolated quantum many-body systems is a fundamental and complex problem in modern physics, with profound implications for our understanding of the universe. Despite its importance, the realization of experimentally accessible and well-isolated quantum many-body systems remains a challenge. In recent years, however, significant progress has been made in this field, largely driven by advancements in ultra-cold atom technology.

This book focuses on the experimental investigation of a relaxation phenomenon that occurs in a one-dimensional bosonic Josephson junction. The system under study consists of two 1D quasi Bose-Einstein condensates (QBCs) of rubidium atoms, which are magnetically trapped on an atom chip. By employing radio-frequency dressing techniques, the author deforms a single harmonic trap, where the atoms are initially condensed, into a double-well potential. This deformation creates a splitting of the wave function, leading to the preparation of a wide range of initial states by precisely controlling the initial population and relative phase of the two wave packets.

One of the key features of the system is the large spatial separation between the two wells, which allows for the exploration of tunneling regimes. In particular, the author investigates Josephson (plasma) oscillations and macroscopic quantum self-trapping, which are characterized by the relaxation of the system to a phase-locked equilibrium state. These results challenge theoretical predictions and highlight the significant differences between non-equilibrium and equilibrium dynamics, which are typically described by thermodynamics and statistical physics.

To support the experimental findings, the author develops an empirical model that allows for quantitative discussions based on various experimental parameters. This model provides a framework for understanding the complex interplay between the system's parameters and the observed relaxation behavior. The results presented in this book shed light on the complex nature of quantum many-body systems and have important implications for fields such as quantum information science, condensed matter physics, and astrophysics.

In conclusion, the experimental study of the relaxation phenomenon in a one-dimensional bosonic Josephson junction presented in this book represents a significant step forward in our understanding of quantum many-body systems. The use of ultra-cold atoms and advanced experimental techniques has enabled researchers to explore the non-equilibrium dynamics of these complex systems and challenge theoretical predictions. The results obtained have profound implications for various fields of physics and have the potential to revolutionize our understanding of the universe.

Weight: 326g
Dimension: 235 x 155 (mm)
ISBN-13: 9783030528461
Edition number: 1st ed. 2020