Experimental test of entropic noise-disturbance uncertainty relations for spin-1/2 measurements

TL;DR

This paper derives a precise noise-disturbance uncertainty relation for qubit measurements and experimentally verifies it using neutron spin-1/2 systems with an optimal correction method.

Contribution

It provides the first experimental validation of a tight, state-independent noise-disturbance relation for spin-1/2 measurements in quantum mechanics.

Findings

Experimental results saturate the uncertainty relation with optimal correction.

Demonstrates the effectiveness of correction procedures in reducing disturbance.

Validates theoretical predictions for qubit noise-disturbance relations.

Abstract

Information-theoretic definitions for noise and disturbance in quantum measurements were given in Phys. Rev. Lett. 112, 050401 (2014) and a state-independent noise-disturbance uncertainty relation was obtained. Here, we derive a tight noise-disturbance uncertainty relation for complementary qubit observables and carry out an experimental test. Successive projective measurements on the neutron's spin-1/2system, together with a correction procedure which reduces the disturbance, are performed. Our experimental results saturate the tight noise-disturbance uncertainty relation for qubits when an optimal correction procedure is applied.