Control of entanglement and two-qubit quantum gates with atoms crossing a detuned optical cavity

TL;DR

This paper presents a method to generate and control entanglement between two four-level atoms using a detuned optical cavity and laser, enabling implementation of key two-qubit quantum gates with adjustable parameters.

Contribution

It introduces a novel scheme for entangling atoms and implementing two-qubit gates by controlling atomic velocities and positions within a cavity setup.

Findings

Entanglement degree can be tuned by atom velocity and initial spacing.

Proposes realistic schemes for i-swap, controlled-Z, and CNOT gates.

Analyzes optimal atomic velocities and distances for reliable gate operation.

Abstract

A scheme is proposed to generate an entangled state between two (Lambda-type) four-level atoms that interact effectively by means of a detuned optical cavity and a laser beam that acts perpendicularly to the cavity axis. It is shown how the degree of entanglement for two atoms passing through the cavity can be controlled by manipulating their velocity and the (initial) distance between the atoms. In addition, three realistic schemes are suggested to implement the two-qubit gates within the framework of the suggested atom-cavity-laser setup, namely, the i-swap gate, controlled-Z gate and the controlled-NOT gate. For all these schemes, we analyze and discuss the atomic velocities and inter-atomic distances for which these gates are realized most reliably.