Quantum tomography for quantum systems optimization

TL;DR

This paper explores how quantum tomography can be used to estimate and correct errors in quantum state transformations, enabling more accurate quantum gate operations despite imperfections.

Contribution

It introduces a method to estimate preparation and measurement errors from experiments and uses these estimates to build a robust quantum tomography model for error correction.

Findings

Accurately reconstructs unitary errors of single-qubit gates.

Enables transformations close to ideal despite gate imperfections.

Mitigates cross-talk in single-qubit gates.

Abstract

Debugging quantum states transformations is an important task of modern quantum computing. The use of quantum tomography for these purposes significantly expands the range of possibilities. However, the presence of preparation and measurement errors complicates the practical use of this procedure. In this work, we investigate the possibility of estimating these errors from experiment. These estimates are subsequently used to build a robust quantum tomography model. The model allows one to accurately reconstruct unitary errors of single-qubit gates. We show that, having such imperfect single-qubit gates with pre-estimated errors, one can obtain transformations close to ideal ones. A similar approach can also significantly mitigate single-qubit gates cross-talk.