Unconventional geometric quantum phase gates with a cavity QED system

TL;DR

This paper presents a novel method for implementing two-qubit quantum phase gates using geometric phases in a cavity QED system, which is robust against atomic decay and cavity loss.

Contribution

It introduces an unconventional geometric phase shift scheme where atoms interact with a detuned cavity and classical field without transitions, enhancing gate robustness.

Findings

The scheme achieves high fidelity two-qubit gates.

The method is insensitive to atomic spontaneous emission.

The cavity mode remains disentangled, reducing decoherence.

Abstract

We propose a scheme for realizing two-qubit quantum phase gates via an unconventional geometric phase shift with atoms in a cavity. In the scheme the atoms interact simultaneously with a highly detuned cavity mode and a classical field. The atoms undergo no transitions during the gate operation, while the cavity mode is displaced along a circle in the phase space, aquiring a geometric phase conditional upon the atomic state. Under certain conditions, the atoms are disentangled with the cavity mode and thus the gate is insensitive to both the atomic spontaneous emission and the cavity decay.