A powered full quantum eigensolver for energy band structures

TL;DR

This paper introduces the powered full quantum eigensolver (P-FQE), a quantum algorithm that improves energy band structure calculations, demonstrating feasibility on NISQ devices with numerical tests on graphene and Weyl semimetals.

Contribution

The paper proposes the P-FQE algorithm, enhancing success probability and robustness for energy spectra determination on noisy quantum hardware, with experimental validation.

Findings

Exponential increase in success probability under certain conditions

Feasibility demonstrated on superconducting quantum computers

Applicable to complex materials like graphene and Weyl semimetals

Abstract

There has been an increasing research focus on quantum algorithms for condensed matter systems recently, particularly on calculating energy band structures. Here, we propose a quantum algorithm, the powered full quantum eigensolver(P-FQE), by using the exponentiation of operators of the full quantum eigensolver(FQE). This leads to an exponential increase in the success probability of measuring the target state in certain circumstances where the number of generating elements involved in the exponentiation of operators exhibit a log polynomial dependence on the number of orbitals. Furthermore, we conduct numerical calculations for band structure determination of the twisted double-layer graphene. We experimentally demonstrate the feasibility and robustness of the P-FQE algorithm using superconducting quantum computers for graphene and Weyl semimetal. One significant advantage of our algorithm is its ability to reduce the requirements of extremely high-performance hardware, making it more suitable for energy spectra determination on noisy intermediate-scale quantum (NISQ) devices.