Error-compensation measurements on polarization qubits

TL;DR

This paper introduces an error-compensation method for polarization qubit measurements that significantly reduces systematic errors, enhancing accuracy in quantum optical experiments.

Contribution

It presents a novel error-compensation design for projective measurements on polarization qubits, reducing systematic errors to second order and improving measurement precision.

Findings

Achieved a 20-fold reduction in systematic error in quantum state tomography.

Reduced phase and angle errors in polarization measurement devices.

Enhanced measurement accuracy for high-precision quantum optics applications.

Abstract

Systematic errors are inevitable in most measurements performed in real life because of imperfect measurement devices. Reducing systematic errors is crucial to ensuring the accuracy and reliability of measurement results. To this end, delicate error-compensation design is often necessary in addition to device calibration to reduce the dependence of the systematic error on the imperfection of the devices. The art of error-compensation design is well appreciated in nuclear magnetic resonance system by using composite pulses. In contrast, there are few works on reducing systematic errors in quantum optical systems. Here we propose an error-compensation design to reduce the systematic error in projective measurements on a polarization qubit. It can reduce the systematic error to the second order of the phase errors of both the half-wave plate (HWP) and the quarter-wave plate (QWP) as well as the angle error of the HWP. This technique is then applied to experiments on quantum state tomography on polarization qubits, leading to a 20-fold reduction in the systematic error. Our study may find applications in high-precision tasks in polarization optics and quantum optics.