In this project, non-equilibrium dynamics in systems of cold atoms and molecules is being explored, as motivated by the unique properties of those systems. The goals are (i) to obtain a better understanding of non-equilibrium dynamics in strongly interacting systems, and (ii) to use non-equilibrium dynamics as a benchmark for characterizing where quantum simulators can be used to explore physics beyond what is possible with classical simulations. In the first part of the project we are studying (a) paradigms of transport dynamics, including the engineering and measurement of currents by coupling the system to a reservoir gas or a cavity mode, as well as purely coherent propagation of excitations engineered in the system; and (b) dynamics in the presence of dipolar interactions, as motivated by recent experimental developments with polar molecules, including the time-dependence of phase transition processes and thermalization of excitations. In each case, the dynamics are bein explored using a combination of analytical techniques and numerical methods, including time-dependent Density Matrix Renormalisation Group methods for 1D systems. Extensions of these methods to the treatment of dynamics with long range interactions will also be investigated. In the second part of the project, we explore possibilities to measure entanglement entropies in experiments, and use these measurements to gain a deeper understanding of many-body dynamics in these systems.
Understanding the non-equilibrium dynamics of microscopic many-particle systems is crucial to the description of very fundamental phenomena occurring in nature, including how a gas of particles reaches thermal equilibrium, and how moving conduction electrons in solids behave in quantum transport processes. Recent developments in experiments with ultracold gases of atoms and molecules have made it possible to explore such non-equilibrium dynamics in highly controllable systems, which can be manipulated and measured by well-understood processes in laser fields. In the research part of this project, we investigate how the unique properties of these systems, which are now available in the laboratory can be used to gain insight into fundamental aspects of non-equilibrium dynamics, including transport processes and thermalization. We will look to gain a deeper understanding of these process through our calculations, and to set a roadmap for the exploration of these phenomena in potential future experiments. We will also investigate means to measure the quantum mechanical entanglement in these experiments, which could be used both to gain further insight into the dynamics, and to demonstrate regimes where a quantum mechanical experiment realizes dynamics that go beyond what is computable with state-of-the-art numerical methods. The broader impacts of the supported work will also be enhanced by the education part of this project, where we will run a series of workshops in which basic concepts in quantum mechanics are explained to high-school teachers based on illustrative examples from current technologies, as well as from the research in this project. With the teachers we will explore possibilities and develop tools to communicate basic concepts in modern physics research to high school students.
