Elisabeth Giacobino (Laboratoire Kastler Brossel) - Jeudi 9 janvier.
For quantum information, critical resources are quantum memories, which enable the storage of quantum data. They will also allow the distribution of entanglement at large distances, in order to overcome transmission losses, since the no-cloning theorem prevents the amplification of a quantum signal.
A quantum memory relies on an efficient coupling between light and matter, allowing reversible mapping of quantum photonic information in and out of the material system. Our system involves the transfer of quantum information from light to atoms (writing) and back from atoms to light (retrieval), using electromagnetically induced transparency (EIT) in three-level transitions in a cold cesium atomic ensemble.
This set-up has allowed efficient storage of single photons carrying orbital angular momentum (OAM). Single photons carrying OAM are promising for the implementation of qubits and qudits since OAM constitutes a quantized and infinite space. Interfacing them with quantum memories opens the way to their use in quantum networks.
You can also watch this video on the multimedia site ENS :savoirs.ens.fr