Error-mitigated photonic variational quantum eigensolver using a single-photon ququart

TL;DR

This paper demonstrates an experimental photonic variational quantum eigensolver using single-photon ququarts with error mitigation, accurately estimating molecular ground state energies despite noise.

Contribution

It introduces a resource-efficient photonic VQE with error mitigation using four-dimensional single-photon states for molecular energy estimation.

Findings

Successfully estimates the ground state energy of He-H$^{+}$.

Demonstrates robustness against noise with quantum error mitigation.

Accurately models the bond dissociation curve.

Abstract

We report the experimental resource-efficient implementation of the variational quantum eigensolver (VQE) using four-dimensional photonic quantum states of single-photons. The four-dimensional quantum states are implemented by utilizing polarization and path degrees of freedom of a single-photon. Our photonic VQE is equipped with the quantum error mitigation (QEM) protocol that efficiently reduces the effects of Pauli noise in the quantum processing unit. We apply our photonic VQE to estimate the ground state energy of He--H$^{+}$ cation. The simulation and experimental results demonstrate that our resource-efficient photonic VQE can accurately estimate the bond dissociation curve, even in the presence of large noise in the quantum processing unit.