Wu, Hua and George, Richard and Wesenberg, Janus and Molmer, Klaus and Schuster, David and Schoelkopf, Robert and Itoh, Koehi and Ardavan, Arzhang and Morton, John and Briggs, Andrew (2010) Storage of multiple coherent microwave excitations in an electron spin ensemble. Physical review letters, 105 (14): 140503. ISSN 1079-7114
Abstract
Strong coupling between a microwave photon and electron spins, which could enable a long-lived quantum memory element for superconducting qubits, is possible using a large ensemble of spins. This represents an inefficient use of resources unless multiple photons, or qubits, can be orthogonally stored and retrieved. Here we employ holographic techniques to realize a coherent memory using a pulsed magnetic field gradient and demonstrate the storage and retrieval of up to 100 weak 10 GHz coherent excitations in collective states of an electron spin ensemble. We further show that such collective excitations in the electron spin can then be stored in nuclear spin states, which offer coherence times in excess of seconds.