I am a physicist specialising in the theory of quantum fluids in cold atoms and superconductors. Together with my collaborators, we are interested in discovering and understanding novel phenomena in far-from-equilibrium scenarios. We employ both analytical and numerical tools to model the dynamics of various many-body systems.

Further details about our research can be found in the research and publications sections.

Research highlights are shown in the gallery below -- click the pictures for more information.

Observation of a Dissipative Time Crystal (Viewpoint, News)
Dynamical control of order in a cavity-BEC system (News)
Emergent limit cycles and time crystal dynamics in an atom-cavity system
Higgs time crystal in a high-Tc superconductor (News)
Center-of-mass motion as a sensitive convergence test for variational multi-mode quantum dynamics
Therrmalization in closed quantum systems: semiclassical approach

Recent Activities

23 July 2021

Observation of a dissipative time crystal

Together with collaborators from the University of Hamburg, we were able to create a time crystal that is exposed to the environment in a controlled way. Using a Bose-Einstein condensate inside an optical cavity, we demonstrate that periodic modulation of the light-mater coupling may lead to a periodic switching of the spatial configuration of the atoms between two sublattices of a chequerboard pattern. More interestingly, the complete cycle requires two driving periods suggesting that time-translation symmetry is broken - a hallmark of time crystals.

Our work represents a crucial step in potentially making this phase of matter useful since almost all time crystals require isolation from the environment. On a more fundamental level, we provide a prototypical example of interesting phases arising from the complex interplay between many-body interaction, driving, and dissipation.


Physical Review Letter (Editors' Suggestion)

Commentary articles:

"Time crystals in Open Systems" by Z. Gong and M. Ueda

"Quantum time crystals open up" by P. Ball

News articles and interviews:

"The first experimental realization of a dissipative time crystal" (Phys.org)

"Zu verrückt, um falsch zu sein" (Die Zeit)

"Auf den Spuren von Raum und Zeit" (Forschung und Lehre)

10 June 2021

Higgs mode mediated enhancement of interlayer transport in high-Tc cuprate superconductors

The famous Higgs boson in particle physics has an analogue in condensed matter, which is aptly called the Higgs mode. Beyond fundamental and theoretical interests, can we possibly use this elusive mode for practical purposes?

In our recently published work, the answer appears to be "yes". In particular, we predict that the transport property of cuprate superconductors can be enhanced by essentially shining them with light at a frequency slightly above the Higgs frequency. The resulting oscillation of the Higgs mode then leads to a parametric amplification of the superconducting response.


Physical Review B

25 February 2021

Dynamical density wave order in an atom–cavity system

We demonstrate theoretically and experimentally the emergence of a dynamical density wave order by resonant driving in an atom-cavity system. The oscillating density grating, associated with this order, suppresses the scattering of photons into the cavity.


New Journal of Physics

11 November 2020

Higgs time crystal in a high-temperature superconductor

Manipulating equilibrium properties via non-equilibrium dynamics has led to novel phenomena, such as light-induced superconductivity. Recently, a new class of genuine dynamical states was discovered called time crystals. The rigidity of emergent oscillations in a time crystal makes it a promising tool for precision frequency generation. Here, we propose to induce a time crystal in a high-Tc superconductor by driving a sum resonance between two fundamental excitations in systems with broken U(1) symmetry - the Higgs mode and the phase or plasma mode. Our work advances light-assisted dynamical control of solids towards genuine non-equilibrium states, which have no counterpart in equilibrium.


Physical Review Research

Press coverage