Quantum process tomography of a single solid state qubit

TL;DR

This paper demonstrates quantum process tomography on a single solid state qubit, specifically a Nitrogen-Vacancy center in diamond, analyzing decoherence effects over different time periods.

Contribution

It provides a detailed experimental implementation of quantum process tomography on a solid state qubit, including analysis of decoherence and process validation.

Findings

Successfully reconstructed quantum processes using $hind affine map representations

Quantified discrepancies between estimated and physically valid processes

Analyzed decoherence effects over multiple time intervals

Abstract

We present an example of quantum process tomography performed on a single solid state qubit. The qubit used is two energy levels of the triplet state in the Nitrogen-Vacancy defect in Diamond. Quantum process tomography is applied to a qubit which has been allowed to decohere for three different time periods. In each case the process is found in terms of the $\chi$ matrix representation and the affine map representation. The discrepancy between experimentally estimated process and the closest physically valid process is noted.