Graduate Program in Physics at UFSC, Florianópolis

THE PHYSICS GRADUATE PROGRAM invites everyone to the seminar: 

Detection of quantum entanglement: experiments with spatially entangled photon pairs 

Stephen Patrick Walborn

Instituto de Física – UFRJ

 Abstract:

The twin photons produced by spontaneous parametric down-conversion have been an exceptional tool for the study of entanglement and quantum information. The spatial correlation of these photons was one of the first properties to be studied. Nevertheless, the convenient and efficient detection of quantum entanglement in the spatial variables is still an active area of research, with possible applications in quantum cryptography and communication. Here we present several experiments performed at the Quantum Optics Laboratory at the Instituto de Física, Universidade Federal do Rio de Janeiro. We present several novel experimental methods to detect the entanglement in the transverse spatial variables of photon pairs. Both methods use spatial light modulators to imprint an appropriate phase profile on the down-converted photons. Our first method uses this phase profile to measure the spatial correlation functions directly. With these, we can evaluate known entanglement witnesses in a more efficient fashion, without the need for a position-dependent detection system. Our second method uses complementary masks to discretize the detection system, again allowing for a more efficient identification of entanglement via a novel entanglement witness.

Date: 17/April/2015 – (friday) – Place: Sala 212 – Auditório do Departamento de Física– Time: 10h15min

5min