SP Seminar @ICTP Stasi Seminar Rm Tuesday 18 December 11am - Monika AIDELSBURGER

[CM Section]

Joint ICTP/SISSA Statistical Physics Seminar

Tuesday 18 December at 11:00 a.m.
Luigi Stasi Seminar Room, first floor, Leonardo building

Monika AIDELSBURGER (LMU Munich, Germany)

Ultracold Atoms in Periodically-Driven Optical Lattices


Floquet engineering is an important tool for the engineering of novel band
structures with interesting properties that go beyond those offered by 
static
systems. Recently, Floquet systems have enabled the generation of Bloch
bands with non-trivial topological properties, such as the Hofstadter and
Haldane model. This led, among others, to direct measurements of
momentum-resolved Berry curvatures and the development of novel techniques
to determine the Chern-number of the artificially generated energy bands.

Besides this success studies of many-body phases in driven systems remain
experimentally challenging in particular due to the interplay between 
periodic
driving and interactions. In driven, time-periodic systems, energy 
conservation
is relaxed due to the absorption and emission of energy quanta from the
drive, and any ergodic system is expected to eventually heat up to infinite
temperatures.

In this talk, I briefly review recent experimental advances in the 
generation
of topological band structures in the non-interacting regime using 
Floquet engineering
and present first studies of interacting atoms in driven 1D lattices. In 
particular, I will
present experimental results obtained with bosonic atoms in driven 1D 
lattices that
directly reveal the existence of parametric instabilities that lead to a 
depletion of the
condensate. Our results point out ways to overcome these limitations in 
future experiments.

In the last part of my talk I will present recent results, where we have 
used a combination
of periodic modulation and strong Hubbard interactions to realize a 
minimal building
block of Z_2 lattice gauge theories. We engineer a minimal coupling 
between matter and
gauge fields using two different internal states of bosonic Rb atoms. 
The obtained
lattice model displays local Z_2 gauge symmetry, which we study 
experimentally in a
double-well potential – the building block of extended lattice models.