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Seeing a Single Photon without Destroying it and Manipulating Entanglement in Atom-Cavity Experiments
  Manne Siegbahn Memorial Lectures

Tuesday 10 October 2000
from 08:00 to 18:00
Speaker : Serge Haroche (Ecole Normale Supérieure, Paris, France )
Abstract :

Light detection is usually a destructive process, in that detectors annihilate photons and convert them into electrical signals, making it impossible to see a single photon twice. But this limitation is not fundamental — quantum non-demolition strategies permit repeated measurements of physically observable quantities, yielding identical results.

The non-destructive measurement of a single photon requires an extremely strong matter-radiation coupling. This can be realized in cavity quantum electrodynamics, where the strength of the interaction between an atom and a photon can overwhelm all dissipative couplings to the environment.

In the experiments reported, an atomic interferometer has been used to measure the phase shift in an atomic wavefunction, caused by a cycle of photon absorption and emission.

The method amounts to a restricted quantum non-demolition measurement, which can be applied only to states containing one or zero photons. It may lead to quantum logic gates based on cavity quantum electrodynamics, and multi-atom entanglement.

Nordita  | Last modified 15 September 2015 12:14  |  HELP