Qubit Coherent Control with Squeezed Light Fields

TL;DR

This paper investigates the use of squeezed light for qubit control, analyzing entanglement and gate errors, and finds that while squeezing influences entanglement, it does not significantly reduce overall gate errors.

Contribution

It provides a comparative analysis of squeezed versus coherent light for qubit control, highlighting the effects of phase on entanglement and error, and discusses the practical implications.

Findings

Squeezing phase affects atom-pulse entanglement and gate error.

Average gate error does not decrease with squeezing and may increase.

Measurement of gate error can indicate entanglement enhancement.

Abstract

We study the use of squeezed light for qubit coherent control and compare it with the coherent state control field case. We calculate the entanglement between a short pulse of resonant squeezed light and a two-level atom in free space and the resulting operation error. We find that the squeezing phase, the phase of the light field and the atomic superposition phase, all determine whether atom-pulse mode entanglement and the gate error are enhanced or suppressed. However, when averaged over all possible qubit initial states, the gate error would not decrease by a practicably useful amount and would in fact increase in most cases. We discuss the possibility of measuring the increased gate error as a signature of the enhancement of entanglement by squeezing.