Hyperentanglement-enabled Direct Characterization of Quantum Dynamics

TL;DR

This paper demonstrates a hyperentanglement-assisted method for efficiently characterizing quantum processes with fewer measurements and high fidelity, advancing quantum process tomography techniques.

Contribution

It introduces an entanglement-assisted direct characterization method that reduces experimental configurations needed for quantum process tomography using hyperentangled photons.

Findings

Achieved single-qubit process fidelities up to 98.2%.

Reduced experimental configurations to one-third of standard methods.

Demonstrated compensation for Bell-state measurement errors.

Abstract

We use hyperentangled photons to experimentally implement an entanglement-assisted quantum process tomography technique known as Direct Characterization of Quantum Dynamics. Specifically, hyperentanglement-assisted Bell-state analysis enabled us to characterize a variety of single-qubit quantum processes using far fewer experimental configurations than are required by Standard Quantum Process Tomography (SQPT). Furthermore, we demonstrate how known errors in Bell-state measurement may be compensated for in the data analysis. Using these techniques, we have obtained single-qubit process fidelities as high as 98.2% but with one-third the number experimental configurations required for SQPT. Extensions of these techniques to multi-qubit quantum processes are discussed.