Study of two-photon deterministic, passive quantum logical gates

Julio R. Gea-Banacloche, Leno M. Pedrotti

We use the ``modes of the universe'' approach to study a cavity-mediated two-photon logical gate recently proposed by Koshino, Ishizaka, and Nakamura. We clarify the relationship between the more commonly used input-output formalism and that of Koshino et al. and show that some elements of this gate had been anticipated by other authors. We conclude that their proposed gate can work both in the good and bad cavity limits, provided only that the pulses are long enough. Our formalism allows us to estimate analytically the size of the various error terms and to follow the spectral evolution of the field+cavity system in the course of the interaction.

Hwang Lee, Jonathan P. Dowling, Federico M. Spedalieri

William Konyk, Julio R. Gea-Banacloche

We show that an array of identical two-level systems coupled losslessly to a one-dimensional waveguide is able to realize a high-fidelity conditional phase shift useful for quantum logic. We propose two arrangements of emitters (one that relies on direct interactions between the emitters, and one that does not), and describe possible physical realizations and limitations.

Wolfgang Freudenberg, Masanori Ohya, NATALIYA TURCHINA +1 more

Adrien Borne, Orel Bechler, Serge Rosenblum +12 more

Using single-photon Raman interaction, we demonstrate a deterministic and passive SWAP gate and quantum memory between the states of a single photon and a single 87Rb atom coupled to high-Q microresonator.

Александр Алексеевич Горбацевич, Н. М. Шубин