Fred Jendrzejewski

Juniorprofessor and part of the effort to build Synthetic Quantum Systems here at the Kirchhoff-Institut. As such I am the new team leader of the NaLi experiment, which I took over from Markus Oberthaler.

Current Research

Ultracold atoms have become a remarkable tool to study complex systems with extremely high precision. Here, we employ a mixture of ultracold atoms to study the dynamics of particles that are immersed in a quantum environment.

-----------------------------------------------

We are always looking for motivated and talented master and PhD students. Please contact me directly for more informations on open projects.

-----------------------------------------------

Previous research

Postdoctoral research

During my postdoctoral research I joined the laser cooling group around Bill Philipps and Gretchen Campbell at the Joint Quantum Institute to explore the new possibilities of atomic ciruits as measurement devices. 

These studies are based on the premise that new highly controlled materials, like ultracold atomic gases, can lead to new devices. This approach allowed for the development of transistors, superconducting magnetometers or utrastable atomic clocks. We were therefore investigating simple ring geometries with Bose-Einstein-condensates to test their potential as atomtronic quantum interference devices [1,2,3].

Refs:

[1] Eckel, S. et al. Hysteresis in a quantized superfluid ‘atomtronic’ circuit. Nature 506, 200 (2014).

[2] Jendrzejewski, F. et al. Resistive Flow in a Weakly Interacting Bose-Einstein Condensate. Phys. Rev. Lett. 113, 045305 (2014).

[3] Eckel, S. et al. Interferometric Measurement of the Current-Phase Relationship of a Superfluid Weak Link. Phys. Rev. X 4, 031052 (2014).

PhD research

I performed my PhD studies at the Institute d'Optique on the topic of disordered systems. Remarkably, quantum interference can fundamentally alter the transport when a disordered potential is present, an effect known as localization. In its most dramatic manifestation it can even lead to the full suppression of transport, i.e. Anderson localization.

Observing the expansion of a Bose-Einstein condensate in a strong light disorder, we were able to demonstrate Localization of matterwaves in three dimensions. This case is of special interest as it is has proven experimentally challenging for several decades and theoretical predictions are notoriously hard [1].

Further, we could observe directly Coherent backscattering of ultracold atoms, which is a direct signal of the role of quantum coherence in quantum transport in disordered media [2].

Refs:

[1] Jendrzejewski, F. et al. Three-dimensional localization of ultracold atoms in an optical disordered potential. Nat. Phys. 8, 398 (2012).

[2] Jendrzejewski, F. et al. Coherent Backscattering of Ultracold Atoms. Phys. Rev. Lett. 109, 195302 (2012).

 
up
Fred Jendrzejewski