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Assessment of a quantum phase gate operation based on nonlinear optics

S. Rebic·C. Ottaviani·G. Di Giuseppe·D. Vitali·P. Tombesi
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Abstract

We analyze in detail the proposal for a two-qubit gate for travelling single-photon qubits recently presented by C. Ottaviani \emph{et al}. [Phys. Rev. A \textbf{73}, 010301(R) (2006)]. The scheme is based on an ensemble of five-level atoms coupled to two quantum and two classical light fields. The two quantum fields undergo cross-phase modulation induced by electromagnetically induced transparency. The performance of this two-qubit quantum phase gate for travelling single-photon qubits is thoroughly examined in the steady-state and transient regimes, by means of a full quantum treatment of the system dynamics. In the steady-state regime, we find a general trade-off between the size of the conditional phase shift and the fidelity of the gate operation. However, this trade-off can be bypassed in the transient regime, where a satisfactory gate operation is found to be possible, significantly reducing the gate operation time.

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S. Rebic, C. Ottaviani, G. Di Giuseppe, D. Vitali, P. Tombesi. 2006-05-11. Assessment of a quantum phase gate operation based on nonlinear optics. https://doi.org/10.1103/physreva.74.032301

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