Title: Benchmarking Adaptive Variational Quantum Eigensolvers

Abstract

By design, the variational quantum eigensolver (VQE) strives to recover the lowest-energy eigenvalue of a given Hamiltonian by preparing quantum states guided by the variational principle. In practice, the prepared quantum state is indirectly assessed by the value of the associated energy. Novel adaptive derivative-assembled pseudo-trotter (ADAPT) ansatz approaches and recent formal advances now establish a clear connection between the theory of quantum chemistry and the quantum state ansatz used to solve the electronic structure problem. Here we benchmark the accuracy of VQE and ADAPT-VQE to calculate the electronic ground states and potential energy curves for a few selected diatomic molecules, namely H ₂ , NaH, and KH. Using numerical simulation, we find both methods provide good estimates of the energy and ground state, but only ADAPT-VQE proves to be robust to particularities in optimization methods. Another relevant finding is that gradient-based optimization is overall more economical and delivers superior performance than analogous simulations carried out with gradient-free optimizers. The results also identify small errors in the prepared state fidelity which show an increasing trend with molecular size.

Authors:

Claudino, Daniel; Wright, Jerimiah; McCaskey, Alexander J.; Humble, Travis S.

Publication Date:

2020-12-04

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division

OSTI Identifier:

1731007

Alternate Identifier(s):

OSTI ID: 1771891

Grant/Contract Number:  

3ERKCG12; AC05-00OR22725

Resource Type:

Published Article

Journal Name:

Frontiers in Chemistry

Additional Journal Information:

Journal Name: Frontiers in Chemistry Journal Volume: 8; Journal ID: ISSN 2296-2646

Publisher:

Frontiers Media SA

Country of Publication:

Switzerland

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; ADAPT-VQE; quantum computing; quantum chemistry; VQE; potential energy scan; state fidelity