We have demonstrated a quantum memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency, and with an acceptance bandwidth of δf=0.66 GHz. This memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. These results were published in Physical Review Letters 119, 060502.
We congratulate Boris Décamps for winning a poster prize at the International Conference on Laser Spectroscopy 2017. His poster was entitled Coherence Times, EPR Entanglement, and Bell Correlations in a Bose-Einstein Condensate. He reported on violation of the EPR steering criteria by spatially separated regions of a spin squeezed BEC, as well as N-particle witnesses of Bell correlations, and quantitative models of decoherence that can be used to correct for phase noise.
Congratulations to Philipp Treutlein, whom the American Physical Society recognized in the 2017 iteration of their highly selective Outstanding Referee Program. This year only 150 people of the roughly 60000 currently active referees were honored with this lifetime award. The APS instituted the program in 2008 to thank and recognize those referees, whose efforts not only keep the standards of the journals high, but also help authors improve the quality and readability of their articles.
Congratulations to Janik Wolters, who won a best poster award at the International Conference on Quantum Communication, Measurement and Computing (QCMC) in Singapore. He reported progress towards the storage of single quantum dot photons in a rubidium quantum memory. The experiments were carried out in collaboration with the Warburton group.
The strongest form of correlations between particles are those that violate a Bell inequality. We have detected such Bell correlations between 480 atoms in a Bose-Einstein condensate, using a witness inequality that we derived in collaboration with the theory groups of N. Sangouard and V. Scarani. The results were reported in Science 352, 441-444 (2016).
Dr. Janik Wolters was awarded a Marie-Skłodowska-Curie Fellowship from the European Commission for the project "Cold atom-semiconductor quantum interface" - congratulations! We thank the European Union for the generous support and hope that the project will help to exploit the potential of quantum science to benefit the European economies and societies.
The European Research Council has awarded a Starting Grant to Prof. Philipp Treutlein for the project "Modular mechanical-atomic quantum systems", which is scheduled to start in early 2016. We thank the European Union for generously supporting the Swiss research community.
We record images of microwave fields with sub-100 μm resolution using a microfabricated alkali vapor cell. The setup can additionally image dc magnetic fields, and can be configured to image microwave electric fields. Our technique could prove transformative in the design, characterisation, and debugging of microwave devices and find applications in medical imaging. These results were published in New Journal of Physics 17, 112002 (2015) as a fast track communication.
In collaboration with the Warburton group, we have developed a semiconductor quantum dot single photon source that emits transform-limited photons at 780 nm, the wavelength of the Rubidium D2 line. The quantum dot photons are tuned into exact resonance with hyperfine transitions of natural Rubidium atoms, a key step towards storing them in an atomic quantum memory. These results were published in Phys. Rev. B 92, 245439 (2015)..
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. These results were published in Nature Nanotechnology 10, 55 (2015). See also the news features in Deutschlandfunk and Telebasel.