Individual Addressing in Quantum Computation through Spatial Refocusing

TL;DR

This paper introduces a spatial refocusing method using interference of multiple laser beams to significantly reduce crosstalk noise in quantum computing, enhancing the precision of individual qubit addressing.

Contribution

It presents a novel spatial refocusing scheme applicable to various quantum gates, reducing crosstalk-induced errors with minimal additional resources.

Findings

Crosstalk-induced infidelity can be reduced by several orders of magnitude.

The method is compatible with practical Gaussian laser beams.

A moderate number of correction beams suffices for significant noise reduction.

Abstract

Separate addressing of individual qubits is a challenging requirement for scalable quantum computation, and crosstalk between operations on neighboring qubits remains as a significant source of noise for current experimental implementation of multi-qubit platforms. We propose a scheme based on spatial refocusing from interference of several coherent laser beams to significantly reduce the crosstalk noise for any type of quantum gates. A general framework is developed for the spatial refocusing technique, in particular with practical Gaussian beams, and we show under typical experimental conditions, the crosstalk-induced infidelity of quantum gates can be reduced by several orders of magnitude with a moderate cost of a few correction laser beams.