Experimental estimation of one-parameter qubit gates in the presence of phase diffusion

TL;DR

This paper investigates the fundamental limits and optimal strategies for estimating one-parameter qubit gates affected by phase diffusion, including experimental validation of adaptive estimation methods.

Contribution

It introduces an optimal estimation scheme for polarization qubits under phase diffusion and demonstrates an adaptive method to achieve this optimality experimentally.

Findings

Established quantum limits for phase-diffused qubit gate estimation

Developed and experimentally validated an adaptive estimation protocol

Identified optimal probes and measurements for the task

Abstract

We address estimation of one-parameter qubit gates in the presence of phase diffusion. We evaluate the ultimate quantum limits to precision, seek for optimal probes and measurements, and demonstrate an optimal estimation scheme for polarization qubits. An adaptive method to achieve optimal estimation in any working regime is also analyzed in details and experimentally implemented.