Measurement Back Action on Qubit Systems by a Cavity Probe

TL;DR

This paper develops a theoretical framework to analyze how a cavity probe's measurement back action affects quantum entanglement in multi-qubit systems, highlighting the importance of entanglement back action in quantum measurement sensitivity.

Contribution

It introduces an exact quantum state stochastic Schrödinger equation approach to study measurement back action on entanglement in multi-qubit systems within a cavity probe.

Findings

Back action influences quantum entanglement dynamics.

Measurement sensitivity analysis must include entanglement back action.

Provides a new theoretical method for studying measurement effects.

Abstract

We study the back action on a coupled multiple-qubit system induced by a quantum cavity probe in a non-demolition quantum measurement scheme. The exact quantum state stochastic Schr\"{o}dinger equation is derived to systematically investigate the dynamics of quantum entanglement of the multiple-qubit system inside the cavity probe. Although quantum entanglement cannot be directly measured through experiments, the back action on quantum entanglement in the multi-qubit system is witnessed by applying the exact quantum state stochastic equations. Our results demonstrate that the analysis on the sensitivity of the quantum measurement should include not only the standard quantum limit of the canonical operators, but also the back action on the quantum entanglement. Our new method proposed a theoretical approach to investigate the effects of the measurement back action on the multi-qubit systems induced by the cavity probe.