Research projects

dipole trap

Single atom quantum interfaces

One of the cleanest quantum information storage systems are internal degrees of freedom of single atoms. We want to understand the basics of atom-light interaction for future quantum interfaces.


Entanglement tests with photon pairs

Bell inequalities are a powerful tool in discriminating whether nature is better described by classical or non-local theories. We explore how close an experiment can approach the prediction of quantum physics, and explore an algorithmic alternative of assessing non-locality.


Four-wave mixing

Efficent transfer of entanglement in photons to stationary qubits such as atoms requires narrowband photons. We generate narrowband correlated photon pairs via four wave mixing in a Rubidium-87 MOT.

random number

Quantum Random Numbers

We use quantum noise in a photodetection process for a fast compact physical random number generator.

stellar inteferometry

Stellar Interferometry, revisited

Photon bunching measurements allow for high precision probing of spatial and temporal properties of thermal light sources. We improve the bunching signal via spectral filtering and investigate possible applications in astronomy.

type-2 PDC

Sources of entangled photon pairs

Most quantum information experiments depend on strong sources for entangled photons. We try to improve the entanglement quality, brightness and usability of such sources based on parametric down conversion.


Quantum cryptography

A practical  application of quantum information ideas to establish a secure communication channel. Our experiments implement entanglemend-based cryptography protocols via a free-space optical link.

Past projects


Magnetometry with diamond NV centers

Single NV centers in diamond are photostable single quantum systems that can be used for a number of quantum information processing tasks. Here we use the Larmor precession in the electronic ground states of an NV center as a highly sensitive microscopic magnetic field probe.

information leakage

Quantum hacking

Quantum key distribution can be really secure if you have a clean system and you know everything about it. Realistic systems, however, do have issues, and we look into physical vulnerabilities of representative implementations.

joint spectrum

Multiphoton entanglement

Complex quantum information protocols can be based on multiphoton entanglement. We investigate preparation of such states via parametric down conversion with femtosecond pump pulses.


Quantum state estimation

Optical quantum communication and measurements require often complete quantum state estimation. Our minimal polarimeter topologies allow efficient tomography of single and multiphoton states.