Group Seminar at LMU and via Zoom: Novel phase transitions in driven and quasiperiodic optical lattice
Ulrich Schneider, University of Cambridge, UK
Group Seminar at LMU in seminar room H 107 and via zoom
Tuesday, September 27, 9.00 am (MEZ)
Phase transitions and critical phenomena have been at the heart of many-body physics—and quantum simulations with ultracold atoms—from the beginning. While almost all phase transitions in cold atoms systems are continuous, there is a renewed interest in discontinuous (first-order) phase transitions and the associated quantum metastability. We experimentally combine an optical lattice with a resonant Floquet drive that couples the lowest two bands of the lattice. This coupling can not only induce the superfluid to Mott insulator transition but furthermore enables us to control its character and turn the Mott transition into discontinuous transition. In addition, I will give an update on our work on optical quasicrystals. Quasicrystals are a novel form of condensed matter that is not periodic, but nonetheless long-range ordered. They can be described by self-similar, fractal tilings containing more than one type of unit cell, such as the celebrated Penrose tiling. Many foundational concepts of periodic systems such as Blochwaves or Brillouin zones are not applicable to quasicrystals, thereby giving rise to new physics. In particular, quasiperiodic potentials might host 2D Many-Body Localized states and give rise to novel topological effects.