An Error Model for the Cirac-Zoller CNOT gate

TL;DR

This paper models realistic imperfections in the Cirac-Zoller CNOT gate for ion-trap quantum computing, focusing on laser pulse errors that cause information leakage and affect gate fidelity.

Contribution

It introduces a novel error model for the Cirac-Zoller CNOT gate considering physically realistic laser pulse imperfections.

Findings

Laser pulse imperfections cause information leakage.

Imperfections lead to both unitary and non-unitary errors.

The model highlights the impact of auxiliary state leakage.

Abstract

In the framework of ion-trap quantum computing, we develop a characterization of experimentally realistic imperfections which may affect the Cirac-Zoller implementation of the CNOT gate. The CNOT operation is performed by applying a protocol of five laser pulses of appropriate frequency and polarization. The laser-pulse protocol exploits auxiliary levels, and its imperfect implementation leads to unitary as well as non-unitary errors affecting the CNOT operation. We provide a characterization of such imperfections, which are physically realistic and have never been considered before to the best of our knowledge. Our characterization shows that imperfect laser pulses unavoidably cause a leak of information from the states which alone should be transformed by the ideal gate, into the ancillary states exploited by the experimental implementation.