Minimizing back-action through entangled measurements

Abstract

When an observable is measured on an evolving coherent quantum system twice, the first measurement generally alters the statistics of the second one, which is known as measurement back-action. We introduce, and push to its theoretical and experimental limits, a novel method of back-action evasion, whereby entangled collective measurements are performed on several copies of the system. This method is inspired by a similar idea designed for the problem of measuring quantum work [Perarnau-Llobet \textit{et al}., (https://doi.org/10.1103/PhysRevLett.118.070601) Phys. Rev. Lett. \textbf{118}, 070601 (2017)]. By utilizing entanglement as a resource, we show that the back-action can be extremely suppressed compared to all previous schemes. Importantly, the back-action can be eliminated in highly coherent processes.

References in corpus (12)

• Fluctuation theorems: Work is not an observable
• Negativity and contextuality are equivalent notions of nonclassicality
• Stronger uncertainty relations for the sum of variances
• Tunable ion-photon entanglement in an optical cavity
• Anomalous Weak Values Are Proofs of Contextuality
• Non-equilibrium quantum fluctuations of work
• Dynamics of simultaneously measured non-commuting observables
• Sequential weak measurement
• Anomalous Weak Values and the Violation of a Multiple-measurement Leggett-Garg Inequality
• Experimentally reducing the quantum measurement back-action in work distributions by a collective measurement
• Construction of extremal local positive operator-valued measures under symmetry
• Implementation of generalized measurements on a qudit via quantum walks