Quantum Nondemolition Gate Operations and Measurements in Real Time on Fluctuating Signals

TL;DR

This paper demonstrates a broadband optical quantum nondemolition gate capable of real-time measurements on fluctuating signals, enabling advanced quantum information processing and error correction.

Contribution

It introduces a broadband QND gate compatible with non-Gaussian states, expanding capabilities for quantum computation and error correction.

Findings

QND gate bandwidth ~100 MHz

Real-time measurement on fluctuating signals achieved

Compatible with non-Gaussian wave-packet states

Abstract

We demonstrate an optical quantum nondemolition (QND) interaction gate with a bandwidth of about 100 MHz. Employing this gate, we are able to perform QND measurements in real time on randomly fluctuating signals. Our QND gate relies upon linear optics and offline-prepared squeezed states. In contrast to previous demonstrations on narrow sideband modes, our gate is compatible with non-Gaussian quantum states temporally localized in a wave-packet mode, and thus opens the way for universal gate operations and realization of quantum error correction.