The two-qubit controlled-phase gate based on cross-phase modulation in GaAs/AlGaAs semiconductor quantum wells

TL;DR

This paper proposes a practical all-optical two-qubit controlled-phase gate using cross-phase modulation in GaAs/AlGaAs quantum wells, enabling efficient photon-photon entanglement and quantum information processing.

Contribution

It introduces a novel scheme for a two-qubit controlled-phase gate leveraging giant cross-Kerr nonlinearity in semiconductor quantum wells, with a practical method for Bell state discrimination.

Findings

Achieved giant cross-Kerr nonlinearity with matched group velocities

Suppressed linear and self-Kerr optical absorption

Proposed a feasible experimental scheme for Bell state discrimination

Abstract

We present a realization of two-qubit controlled-phase gate, based on the linear and nonlinear properties of the probe and signal optical pulses in an asymmetric GaAs/AlGaAs double quantum wells. It is shown that, in the presence of cross-phase modulation, a giant cross-Kerr nonlinearity and mutually matched group velocities of the probe and signal optical pulses can be achieved while realizing the suppression of linear and self-Kerr optical absorption synchronously. These characteristics serve to exhibit an all-optical two-qubit controlled-phase gate within efficiently controllable photon-photon entanglement by semiconductor mediation. In addition, by using just polarizing beam splitters and half-wave plates, we propose a practical experimental scheme to discriminate the maximally entangled polarization state of two-qubit through distinguishing two out of the four Bell states. This proposal potentially enables the realization of solid states mediated all-optical quantum computation and information processing.