On single qubit quantum process tomography for trace-preserving and nontrace-preserving maps

TL;DR

This paper reviews single-qubit quantum process tomography, deriving explicit constraints for data fitting, revealing tighter bounds on nontrace-preserving processes, and including methods to handle imperfect input states.

Contribution

It provides explicit forms of constraints for quantum process tomography, offering new insights into process matrix structure and bounds for nontrace-preserving maps.

Findings

Derived explicit constraints for process matrix fitting.

Revealed tighter bounds on the trace of nontrace-preserving processes.

Included methods to incorporate imperfect input states.

Abstract

We review single-qubit quantum process tomography for trace-preserving and nontrace-preserving processes, and derive explicit forms of the general constraints for fitting experimental data. These forms provide additional insight into the structure of the process matrix as well as reveal a tighter bound on the trace of a nontrace-preserving process than has been previously stated. We also describe, for completeness, how to incorporate measured imperfect input states.