Welcome to the Ultracold Quantum Gases Group at the Physikalisches Institut of the Ruprecht-Karls-Universität Heidelberg



Our research is focused on ultracold Fermi systems. For more information, please read about our project! If you would like to know more, or if you have some comments or ideas, please don't hesitate to contact us!


Diploma thesis finished

The new BECThe new BEC
Johanna Bohn recently finished her diploma thesis, which describes the setup of our new dipole trap and the molecular BEC we are able to create in this trap.
The thesis can be found here: diplomarbeit_johanna.pdf.


Fermionization of Two Distinguishable Fermions

In our latest paper we make two distinguishable atoms behave as if they were fermions, and verify this by comparing them to two identical fermionic atoms. The paper has been selected as an editor's suggestion by PRL, and was highlighted by a Physics synopsis:
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.108.075303
2 distinguishable vs. 2 identical atoms2 distinguishable vs. 2 identical atoms


New paper published

We sucessfully prepared a tunable quantum system consisting of one to ten fermions. We prepare such a system using ultracold Lithium atoms in a micrometer sized optical dipole trap. Due to Pauli's principle one quantum state in the trap is occupied with one atom per spin state (red and blue balls). By tilting the trap we can control the number of remaining quantum states and thus the number of particles.
Schematic preparation scheme of the tunable few-fermion systemSchematic preparation scheme of the tunable few-fermion system
The paper is published in the current issue of Science. The ArXiv version can be found here and there is also a press release (in German) by the University of Heidelberg.


New Bubble Chamber at the MPI-K

The ultracold quantum gases group proudly present its new bubble chamber implemented at the Max-Planck Institute. Due to space constraints it has been temporarily placed inside Selim's office.

Experimental SetupExperimental Setup

First EventFirst Event


Another diploma thesis finished

Philipp Simon recently handed in his diploma thesis, which further characterizes the new MOT and Zeeman slower and can be found here:

diplomarbeit_philipp.pdf.


New paper published

We have associated an univeral three-body bound state, so called Efimov state, and measured its binding energy as a function of interaction strength with radio-frequency spectroscopy.
The paper has been published in the current issue of Science. The arxiv version can be found here.

Signal of the trimer association (red points) for different interaction strengths.Signal of the trimer association (red points) for different interaction strengths.


New MOT / diploma thesis finished

The new MOTThe new MOT
We recently finished the construction of a new magneto-optical trap (MOT). With loading rates of 3·10^8 and higher, it will serve as a fast and efficient precooling stage for future experiments. The background collision limited lifetime of atoms in the trap is approximately 23 minutes.

More details on the apparatus can be found in Martin Ries' diploma thesis, which was handed in recently. It is now available online: diplomarbeit_martin.pdf.


New Preprint Online

We have conducted a study of atom-dimer scattering in an ultracold three-component Fermi gas consisting of 6Li atoms in three different hyperfine states |1>,|2> and |3>.
For this we have prepared three different mixtures of atoms and dimers and observed their decay via inelastic atom-dimer collisions. In the |1>-|23> atom-dimer mixture we have observed resonant enhancement of the loss at the crossings of two Efimov-like trimer states with the |1>-|23> atom-dimer threshold. We have also found that these trimer states can cause a suppression of |3>-|12> → |1>-|23> exchange reactions in the |3>-|12> mixture, which allows to control the rate constants for these processes.
For more details on these results see arXiv:1003.0600

Two-body loss coefficient of the I1>-I23> mixture vs. magnetic field: the red line is a fit according to universal theory.Two-body loss coefficient of the I1>-I23> mixture vs. magnetic field: the red line is a fit according to universal theory..


First PhD thesis published

Congratulations Timo!
The thesis is available here:
Few-body physics in ultracold Fermi gases