title: Passive CPHASE Gate via Cross-Kerr Nonlinearities.
abstract: A fundamental and open question is whether cross-Kerr nonlinearities can be used to construct a controlled-phase (cphase) gate. Here we propose a gate constructed from a discrete set of atom-mediated cross-Kerr interaction sites with counterpropagating photons. We show that the average gate fidelity F between a cphase and our proposed gate increases as the number of interaction sites increases and the spectral width of the photon decreases; e.g., with 12 sites we find F>99%.
authors: Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, Ontario N2L 2Y5, Canada.
authors: Daniel J
authors: DJ
authors: Brod
authors: Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, Ontario N2L 2Y5, Canada.|Institute for Quantum Computing and Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors: Joshua
authors: J
authors: Combes