We explore fundamental quantum physics with atoms, photons and phonons and harness it for applications in quantum metrology and quantum information. In our experiments we study many-particle entanglement in Bose-Einstein condensates and develop quantum interfaces between atoms and solid-state nanosystems such as mechanical oscillators and semiconductor quantum dots. Our research combines experiment with theory, employing techniques of laser cooling, atom chips, optomechanics, and nanofabrication. A common goal of our activities is to investigate quantum physics in systems of increasing size and complexity.
Engineering strong Hamiltonian interactions between quantum systems is usually only possible over short distances. We demonstrate a new scheme for long-distance interactions mediated by light and use it for a range of experiments in hybrid atom-optomechanics. Our technique opens up a range of opportunities for quantum control and coherent feedback in quantum networks and metrology. The results were reported in Science.
Congratulations to Matteo Fadel, who was awarded a Prix Schläfli of 2019 by the Swiss Academy of Science for an excellent dissertation in the natural sciences. The Prix Schläfli was first awarded in 1866. Since then 104 young talents in different natural science disciplines have been distinguished. You can read Matteo's dissertation here.
For their paper Bell Correlations in a Bose-Einstein Condensate, Roman Schmied, Jean-Daniel Bancal, Baptiste Allard, Matteo Fadel, Valerio Scarani, Philipp Treutlein and Nicolas Sangouard have won the Paul Ehrenfest best paper award for quantum foundations 2017. Pictured (left to right) are Philipp, Jean-Daniel, Matteo, Nicolas, and Roman at the award ceremony in Vienna earlier today.
Have a look at our new review article on "Non-classical states of atomic ensembles: fundamentals and applications in quantum metrology", a joint work of L. Pezzè, A. Smerzi, M. K. Oberthaler, R. Schmied and P. Treutlein. Now published in Rev. Mod. Phys. 90, 035005 (2018).
By directly measuring the spin correlations between spatially separated parts of a spin-squeezed Bose-Einstein condensate we observe entanglement that is strong enough for Einstein-Podolsky-Rosen steering: We can predict measurement outcomes for noncommuting observables in one spatial region on the basis of corresponding measurements in another region with an inferred uncertainty product below the Heisenberg uncertainty bound. This method could be exploited for entanglement-enhanced imaging of electromagnetic field distributions and quantum information tasks. The results were reported in Science 360, 409-413.