Interaction-induced Thouless pumping
In a joint theory-experiment collaboration between the ETH Zurich, Centro
Atomico Bariloche and our group published in
Phys. Rev. X 14, 021049 (2024) , we demonstrate interaction induced charge pumping in a system of
interacting fermions in a quantum gas experiment, supported by numerical
simulations for realistic conditions. This constitutes one of the first
instances of topology in an interacting system. The initial quantized
pumping is eventually surpassed by a breakdown due low-energy spin
excitations, rooted in the many-body physics of the ionic Hubbard model.
The figure shows a sketch of the experimental set-up.
Dynamical quantities of electron phonon systems
In our recent study
Jansen et al., Phys. Rev. B 102, 165155 (2020) , we use a density-matrix renormalization group method combined with
local basis optimization to efficiently compute thermodynamic expectation
values and finite-temperature spectral functions of the Holstein polaron
model. Focusing on the intermediate electron-phonon coupling regime, we
first test our approach by comparing the spectral function to that
obtained with the finite-temperature Lanczos method. We then compute the
electron-emission spectrum and the phonon spectral function. As
temperature is increased, we observe that spectral weight is shifted to
lower frequencies and larger momenta for the electron-emission spectrum.
For the phonon spectral function, larger temperatures allow us to observe
a reflected polaron band.
Delocalization in patterned disorder potentials
Understanding the emergent dynamics of many-body quantum systems in the
presence of disorder remains a key topic in condensed matter theory. In
our recent work
Rev. B 109, 125127 (2024), we investigate the dynamics and entanglement in the presence of a
patterned disorder, where clean sites are periodically immersed into a
disordered system. We demonstrate that this leads to high-entanglement
states in the sea of area law states on finite systems, and consequently,
initial state dependent relaxation dynamics. The figure shows the set-up
and relevant initial states.
