Open Positions
We are always interested in prospective PhD students as well as postdocs. Also, students are encouraged to apply for semester/bachelor/master projects at any time. For information or application, please contact Tilman Esslinger and/or Tobias Donner.
Postdoc Opening
Quantum Simulation of Devices
Transport of fermionic lithium atoms through mesoscopic structures shaped by laser light
Two atomic reservoirs are smoothly connected by a mesoscopic channel, forming a two-terminal
configuration. In this rather unique set-up we measure conductances of small quantum gas samples,
such as two-dimensional films and quantum wires, often with direct
analogies to quantum electronic devices.
Employing ultrahigh-resolution microscope objectives and a Digital
Micromirror Device we generate almost arbitrary optical potentials for
the lithium gas, ranging from single obstacles to optical lattices. This
flexibility together with the unique tunability of interactions in lithium
enables us to probe mesoscopic transport of strongly correlated
matter.
In a recent study we measured quantized conductance through a spin-selective atomic point contact.
A strongly focused laser (red in the upper figure) acts as an optical tweezer or anti-tweezer, i.e. it is
tuned to repel one atomic state (blue) and to attract the other (orange). Although the light is close to
resonance, we are able to observe quantized plateaus of conductance after measuring for several
seconds without detrimental heating. This also gives us the possibility of detecting minute variations in
the number of atoms in the channel, seeing the distance between the conductance plateaus being
modified by a change of only two particles.
In another study we created band and correlated insulators of cold
fermions in a mesoscopic lattice structure, which connected the two
reservoirs. For weak interactions we witnessed the emergence of a band-
insulating phase by observing a conductance gap. As interactions are tuned
from weakly to strongly attractive, we discover that this insulating state
persists, hinting at the presence of a Luther-Emery liquid, a phase
predicted uniquely for one-dimensional structures.
The goal of the project is to identify and characterize non-equilibrium phenomena in strongly correlated
many-body physics. The research is carried out in a small team and a strong background in
experimental quantum gas physics as well as in theoretical many-body physics would be welcome.
Starting time and duration of the PostDoc position are flexible.
References:
[1] M. Lebrat, S. Häusler, P. Fabritius, D. Husmann, L. Corman, and T. Esslinger, Quantized Conductance through a Spin-Selective Atomic Point Contact. Phys. Rev. Lett. 123, 193605 (2019).
[2] M. Lebrat, P. Grišins, D. Husmann, S. Häusler, L. Corman, T. Giamarchi, J.-P. Brantut, and T. Esslinger, Band and Correlated Insulators of Cold Fermions in a Mesoscopic Lattice. Phys. Rev. X 8, 011053 (2018)