Julien Bernu: Overview of quantum optics experiments in ANU

Tuesday, September 23, 2014 3:30 pm - 4:30 pm EDT (GMT -04:00)

Julien Bernu, Australian National University (ANU)

1- Photon number discrimination without photon counting (theory and experiment)
There is been a recent push in quantum optics towards 'hybrid' experiments: experiments combining both continuous variable (CV) and discrete variable (DV) measurements, probing both the particle and wave nature of light, utilising both photon counting and field quadrature detection. Combining these two radically different approaches brings a range of new possibilities, but also comes with great experimental difficulties. I will show how photon counting may be mimicked in some cases using only CV techniques, leading to apparent contradictions with no-go theorems.

2-  Einstein-Podolsky-Rosen (EPR) entanglement distillation using noiseless linear amplification (theory)
I will show how a non-deterministic noiseless amplifier may be used in a lossy EPR entanglement distribution channel to distill entanglement and obtain states that would be impossible otherwise.

3- Cold atom memories for light (experiment)
The Gradient Echo Memory (GEM) protocol pioneered at the ANU and realised in hot vapour cells has given great results. The main problem of the 'hot' experiment lies in the limited decoherence time due to fast atomic motion. Consequently, we started a new memory project with cold atoms. We engineered an ultra high optical depth magneto-optical trap (MOT)  and used it to demonstrate GEM and electromagnetically induced transparency (EIT) with unprecedented results