Amplified quantum non-demolition measurements of optical quadratures using quadratic nonlinearity

TL;DR

This paper introduces a novel quantum non-demolition measurement scheme for optical quadratures using a non-degenerate optical parametric amplifier, enabling amplification without quantum back-action.

Contribution

It proposes a new QND measurement method that amplifies optical quadratures while avoiding quantum back-action, advancing quantum measurement techniques.

Findings

The scheme can amplify quadratures without back-action.

Proper parameter settings enable back-action evasion.

Potential applications in quantum information processing.

Abstract

Quantum non-demolition (QND) measurement is a special technique that allows to evade quantum back-action. In this paper, we propose a new QND measurement scheme of the optical field quadratures based on the non-degenerate optical parametric amplifier. We show that for a proper set of parameters, this scheme can realize a new type of QND measurement, where the quadrature of interest is amplified, but still does not subject to any back action.