Novel Quantum Chemistry Algorithms Based on the Variational Quantum Eigensolver

The variational quantum eigensolver (VQE) approach is currently one of the most promising strategies for simulating chemical systems on quantum hardware. In this work, I will describe a new quantum algorithm and a new set of classical algorithms based on VQE. The quantum algorithm, ADAPT-VQE, shows promise in mitigating many of the known limitations of VQEs: Ansatz ambiguity, local minima, and barren plateaus are all addressed to varying degrees by ADAPT-VQE. The classical algorithm family, O2DX-UCCSD, draws inspiration from VQEs, but is classically solvable in polynomial time. This group of algorithms yields equations similar to those of the linearized coupled cluster theory (LCCSD) but is more systematically improvable and, for X = 3 or X = ∞, can break single bonds, which LCCSD cannot do. The overall aim of this work is to showcase the richness of the VQE algorithm and the breadth of its derivative applications.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2023

Author dc:creator

• Grimsley, Harper Rex

Chair dc:contributor.committeechair

• Mayhall, Nicholas

Committee members dc:contributor.committeemember

• Valeyev, Eduard Faritovich
• Economou, Sophia E.
• Crawford, Daniel

• Quantum Chemistry
• Quantum Computing
• Variational Quantum Eigensolver
• Unitary Coupled Cluster

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:36017

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/113663