Quantum state estimation using weak measurements

TL;DR

This paper investigates quantum state estimation using weak measurements without relying on weak values, demonstrating through simulations that it can outperform traditional projective measurements under certain conditions.

Contribution

It introduces a novel scheme for quantum state estimation using weak measurements without weak values, effective for small ensembles and recyclable measurements.

Findings

Weak measurements cause less disturbance, allowing state rescue.

The proposed method can outperform projective measurements in specific scenarios.

Recycling measurements are more effective with small ensembles.

Abstract

We explore the possibility of using "weak measurements" without "weak value" for quantum state estimation. Since for weak measurements the disturbance caused during each measurement is small, we can rescue the state, unlike for the case of projective measurements. We use this property of weak measurements and design schemes for quantum state estimation for qubits and for Gaussian states. We show, via numerical simulations, that under certain circumstances, our method can outperform the estimation by projective measurements both for qubits and for Gaussian states. It turns out that ensemble size plays an important role and the scheme based on recycling works better for small ensembles.