Circuit-Efficient Qubit-Excitation-based Variational Quantum Eigensolver

TL;DR

This paper introduces a circuit-efficient Qubit-Excitation-Based (QEB) ansatz for VQE, significantly reducing circuit depth and enhancing quantum simulation performance on noisy devices.

Contribution

The paper presents a novel low-depth QEB ansatz within ADAPT-VQE, improving quantum simulation efficiency for electronic structures on noisy quantum hardware.

Findings

Significant reduction in circuit depth compared to previous methods

Effective simulation of ground and excited states for small molecules

Enhanced performance on current noisy quantum hardware

Abstract

The wave function Ansatze are crucial in the context of the Variational Quantum Eigensolver (VQE). In the Noisy Intermediate-Scale Quantum era, the design of low-depth wave function Ansatze is of great importance for executing quantum simulations of electronic structure on noisy quantum devices. In this work, we present a circuit-efficient implementation of two-body Qubit-Excitation-Based (QEB) operator for building shallow-circuit wave function Ansatze within the framework of Adaptive Derivative-Assembled Pseudo-Trotter (ADAPT) VQE. This new algorithm is applied to study ground- and excited-sate problems for small molecules, demonstrating significant reduction of circuit depths compared to fermionic excitation-based and QEB ADAPT-VQE algorithms. This circuit-efficient algorithm shows great promise for quantum simulations of electronic structures, leading to improved performance on current quantum hardware.