University of Basel

Welcome to the quantum atom optics lab

We belong to the Department of Physics of the University of Basel in Switzerland. Our research focuses on the quantum physics of ultracold atoms and on hybrid quantum systems in which atoms interact with solid-state micro- and nanostructures. The main experimental tool is an "atom chip", which allows us to laser-cool, trap, and coherently manipulate neutral atoms at micrometer distances from a chip surface. [more]

Our research combines quantum-optical with solid-state systems and experiment with theory, employing techniques of laser cooling, Bose-Einstein condensation, micro- and nanofabrication.

Group Picture

News from the lab

Sympathetic cooling of a membrane oscillator in a hybrid mechanical-atomic system

We have used ultracold atoms to cool the vibrations of a nanomechanical membrane from room-temperature to 650 mK. While sympathetic cooling with atoms has previously been used to cool other microscopic particles, we extend it to the cooling of an engineered solid-state structure, whose mass is 10 orders of magnitude larger than that of the atoms.
Nature Nanotechnology (2014), see also the news features in Deutschlandfunk and Telebasel.

Two poster prizes for microwave field imaging with atomic vapor cells

Andrew won two poster prizes at the 28th European Frequency and Time Forum in Neuchatel and at the Australian Institute of Physics Congress in Canberra - congratulations! He reported on the application of our microwave field imaging technique to study atom-wall interactions and characterize high-performance vapor cell atomic clocks. The experiments were carried out in collaboration with the Mileti group.

Quantum metrology with a scanning probe atom interferometer

We use a small atomic Bose-Einstein condensate as an interferometric scanning probe to map out a microwave field near a chip surface with a few micrometers resolution. Our interferometer overcomes the standard quantum limit by operating with a many-particle entangled state.
The paper appeared in Phys. Rev. Lett. 111, 143001 (2013).

Microwave field imaging with hot atoms

We have used hot atoms in a vapor cell for imaging of microwave fields near an integrated circuit. Our apparatus is simple and compact and does not require cryogenics or ultra-high vacuum, making this technique interesting for applications.
The paper appeared in Appl. Phys. Lett. 101, 181107 (2012).

Spectroscopy of mechanical dissipation in micro-mechanical membranes

We have measured the frequency dependence of the mechanical quality factor (Q) of SiN membrane oscillators and observed a variation of Q by more than two orders of magnitude. Several distinct resonances in Q were observed that can be explained by coupling to membrane frame modes. [more]
The paper appeared in Applied Physics Letters 99, 143109 (2011).

Realization of an optomechanical interface between atoms and a membrane

We have experimentally realized a hybrid optomechanical system by coupling ultracold atoms to a micromechanical membrane oscillator. We observe both the effect of the membrane vibrations onto the atoms as well as the backaction of the atomic motion onto the membrane. [more]
The paper appeared in Phys. Rev. Lett. 107, 223001 (2011), see also the accompanying Physics Viewpoint.

Quantum state tomography of a spin-squeezed BEC

We have developed a new technique for quantum state tomography on the Bloch sphere and use it to reconstruct the Wigner function of a spin-squeezed Bose-Einstein condensate. [more]
The paper appeared in the New Journal of Physics focus issue on Modern Frontiers of Matter Wave Optics and Interferometry: New J. Phys. 13, 065019 (2011).

Microwave field imaging with ultracold atoms

We have used ultracold atoms for high-resolution imaging of microwave fields near integrated microwave circuits. [more]
The paper appeared on the cover of Applied Physics Letters [APL 97, 051101 (2010)]. For a popular article, see SPS-Communications 33, 10 (2011).