Application of simultaneous and continuous measurement of noncommutative observables: Preparation of the pure ideal quadrature-squeezed state by feedback control

TL;DR

This paper proposes a feedback control scheme using simultaneous continuous measurement of noncommutative observables to generate pure quadrature-squeezed states in a harmonic oscillator, surpassing previous single-observable methods.

Contribution

It introduces a novel feedback control approach based on simultaneous measurement of noncommutative observables to produce ideal squeezed states with arbitrary squeezing levels.

Findings

Pure ideal quadrature-squeezed states can be generated with adjustable squeezing.

The method outperforms single-observable measurement schemes by producing non-ideal squeezed states.

Feedback control parameters determine the quality of the squeezed state.

Abstract

As an application of the simultaneous and continuous measurement of noncommutative observables formulated in our previous paper [C. Jiang and G. Watanabe, Phys. Rev. A 102, 062216 (2020)], we propose a scheme to generate the pure ideal quadrature-squeezed state in a one-dimensional harmonic oscillator system by the feedback control based on such type of measurement of noncommutative quadrature observables. We find that, by appropriately setting the strengths of the measurement and the feedback control, the pure ideal quadrature-squeezed state with arbitrary squeezedness can be produced. This is in contrast to the scheme based on the single-observable measurement and the feedback control, where only nonideal squeezed states with squeezing of the measured quadrature are produced.