The main focus of our research group is the theory of ultracold atoms and solid state systems, with particular emphasis on many-body effects. Our primary research interests are
Many-body dynamics in ultra-cold atom systems
The field of many-body dynamics is one of the fundamental frontiers of condensed matter theory. Ultra-cold atom experiments provide the ideal environment to study this field, because of the high level of tunability and control. We use both numerical methods, such as the Truncated Wigner approximation, and analytical approaches, such as renormalization group ideas, to understand this rich field.
Recent projects include the investigation of a dynamic Kosterlitz-Thouless transition in two dimensional Bose gases, the description of photoconductivity of fermionic atoms in an optical lattice via non-linear dynamics, and superfluid properties of ultra-cold atoms in a toroidal trap.
“Quantum engineering” of many-body phases with ultra-cold atoms
We study many-body phases in ultra-cold atom systems. In particular, the physics of ordered states in lower dimensions has a fascinating richness. We use Luttinger liquid theory, as an analytical tool, and time-evolving block decimation, as a numerical method, to study the quantum phases of one-dimensional systems. The method of functional renormalization group calculations is used to study competing orders of Fermi systems in two dimensions.
Recent projects include the investigation of Fermi gases in an optical lattice that interact via dipolar and quadrupolar interactions. Another recent project was the investigation of one-dimensional Bose-Fermi mixtures in the strong coupling regime.
Advancement of the technology of ultra-cold atom systems
The technological development of cooling and manipulating ultra-cold atoms has been one of the important achievements in physics over the last decades. One of our objectives is to contribute to the technological advancement of the field. We develop ideas for cooling techniques, and study measurement approaches, such as extracting the noise correlations from time-of-flight images.
Recent projects include the detection of counterflow and paired superfluid order via noise correlations and via dipole oscillations.
Ultra-fast dynamics in solid state systems
We investigate how ultra-fast light pulses affect solid state systems. A brief, strong drive can trigger a transient response of a fluctuating system, such as a superconductor at finite temperature. We investigate the properties of these short-lived states both numerically and analytically. Key platforms include high Tc superconductors and graphene.