The Quantum Dynamics Division, led by Gerhard Rempe at the Max Planck Institute of Quantum Optics, is well known for its broad range of activities, ranging from atomic to molecular physics, from quantum optics to quantum gases, and from cavity quantum electrodynamics to quantum information science. Dynamical effects occurring in driven dissipative systems play a pivotal role, in particular when the system constituents are strongly coupled to each other.
A paradigm example of our research is a single atom strongly coupled to a single photon inside an optical resonator of the highest possibly quality. This novel hybrid system is ideal to investigate fundamental nonlinear quantum phenomena of light-matter interaction like photon blockade or the deterministic generation of squeezed light or single photons by means of an atom with one-dimensional radiation characteristics. The system is also the scientifically most advanced implementation of a universal quantum network node capable to produce, store and distribute entanglement over large distances, to teleport information between material memories, and to make quantum computation and long-distance quantum communication with individual qubits scalable.
A complementary system to explore quantum-nonlinear phenomena of light-matter interaction at the level of single photons is an ultracold quantum gas of Bose-Einstein-condensed atoms. Here, the collective response of many atoms, all perfectly at rest, to impinging single photons, in combination with the giant nonlinearity provided by highly excited Rydberg atoms is utilized to realize all-optical information processing devices like single-photon switches and even single-photon transistors featuring gain. The novel ultracold Rydberg system is also perfect for the exploration of strongly correlated quantum systems and even molecules.
Molecules with their complex internal structure open up a plethora of exciting new avenues for research in quantum science including quantum-many body physics and quantum information processing. In fact, the many rotational and vibrational states as well as the permanent electric dipole moment in chemically stable molecules are yet unexplored treasures. Pioneering experiments have been performed in the group by electrically guiding and trapping naturally occurring molecules, by slowing them with a rapidly spinning centrifuge, by cooling them into the low millikelvin regime, corresponding to velocities around a meter per second, and most recently by producing pure low-entropy ensembles of trapped molecules.