Minimum Disturbance Rewards with Maximum Possible Classical Correlations

TL;DR

This paper explores how weak measurements on bipartite quantum systems can maximize information gain while minimizing disturbance, using a cost function based on weak discord and fidelity.

Contribution

It introduces a cost function combining weak discord and fidelity to optimize measurement strength for minimal disturbance and maximal classical correlations.

Findings

Optimal measurement strength balances information gain and disturbance.

Weak measurements can reveal information with minimal state disturbance.

The cost function guides the choice of measurement parameters.

Abstract

Weak measurements done on a subsystem of a bipartite system having both classical and nonClassical correlations between its components can potentially reveal information about the other subsystem with minimal disturbance to the overall state. We use weak quantum discord and the fidelity between the initial bipartite state and the state after measurement to construct a cost function that accounts for both the amount of information revealed about the other system as well as the disturbance to the overall state. We investigate the behaviour of the cost function for families of two qubit states and show that there is an optimal choice that can be made for the strength of the weak measurement.