Photonic variational quantum eigensolver for NISQ-compatible quantum technology

TL;DR

This paper explores the implementation of the variational quantum eigensolver (VQE) algorithm on photonic quantum systems, emphasizing their advantages for practical, NISQ-era quantum computing in solving complex problems.

Contribution

It introduces methodologies for realizing VQE on photonic platforms, demonstrating their potential for scalable and practical quantum computation in noisy environments.

Findings

Photonic systems can implement VQE using multiple qubits or a single qudit.

Photonic platforms operate at room temperature with low decoherence.

Photonic VQE can address a wide range of quantum problems.

Abstract

Quantum computers have the potential to deliver speed-ups for solving certain important problems that are intractable for classical counterparts, making them a promising avenue for advancing modern computation. However, many quantum algorithms require deep quantum circuits, which are challenging to implement on current noisy devices. To address this limitation, variational quantum algorithms (VQAs) have been actively developed, enabling practical quantum computing in the noisy intermediate-scale quantum (NISQ) era. Among them, the variational quantum eigensolver (VQE) stands out as a leading approach for solving problems in quantum chemistry, many-body physics, and even integer factorization. The VQE algorithm can be implemented on various quantum hardware platforms, including photonic systems, quantum dots, trapped ions, neutral atoms, and superconducting circuits. In particular, photonic platforms offer several advantages: they operate at room temperature, exhibit low decoherence, and support multiple degrees of freedom, making them suitable for scalable, high-dimensional quantum computation. Here we present methodologies for realizing VQE on photonic systems, highlighting their potential for practical quantum computing. We first provide a theoretical overview of the VQE framework, focusing on the procedure for variationally estimating ground state energies. We then explore how photonic systems can implement these processes, showing that a wide variety of problems can be addressed using either multiple qubit states or a single qudit state.