J 2022

Best-Practice Aspects of Quantum-Computer Calculations: A Case Study of the Hydrogen Molecule

MIHÁLIKOVÁ, Ivana, Martin FRIÁK, Matej PIVOLUSKA, Martin PLESCH, Martin SAIP et. al.

Basic information

Original name

Best-Practice Aspects of Quantum-Computer Calculations: A Case Study of the Hydrogen Molecule

Authors

MIHÁLIKOVÁ, Ivana (703 Slovakia, belonging to the institution), Martin FRIÁK (203 Czech Republic, belonging to the institution), Matej PIVOLUSKA (703 Slovakia, belonging to the institution), Martin PLESCH (703 Slovakia, belonging to the institution), Martin SAIP (203 Czech Republic, belonging to the institution) and Mojmír ŠOB (203 Czech Republic, guarantor, belonging to the institution)

Edition

MOLECULES, SWITZERLAND, MDPI, 2022, 1420-3049

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10301 Atomic, molecular and chemical physics

Country of publisher

Switzerland

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

Impact factor

Impact factor: 4.600

RIV identification code

RIV/00216224:14310/22:00125831

Organization unit

Faculty of Science

UT WoS

000761013800001

Keywords in English

quantum computers; hydrogen molecule; variational quantum eigensolver; circuit architecture; quantum computing; quantum chemistry; COBYLA; SPSA

Tags

Tags

International impact, Reviewed
Změněno: 22/3/2023 16:01, Mgr. Marie Šípková, DiS.

Abstract

V originále

Quantum computers are reaching one crucial milestone after another. Motivated by their progress in quantum chemistry, we performed an extensive series of simulations of quantum-computer runs that were aimed at inspecting the best-practice aspects of these calculations. In order to compare the performance of different setups, the ground-state energy of the hydrogen molecule was chosen as a benchmark for which the exact solution exists in the literature. Applying the variational quantum eigensolver (VQE) to a qubit Hamiltonian obtained by the Bravyi–Kitaev transformation, we analyzed the impact of various computational technicalities. These included (i) the choice of the optimization methods, (ii) the architecture of the quantum circuits, as well as (iii) the different types of noise when simulating real quantum processors. On these, we eventually performed a series of experimental runs as a complement to our simulations. The simultaneous perturbation stochastic approximation (SPSA) and constrained optimization by linear approximation (COBYLA) optimization methods clearly outperformed the Nelder–Mead and Powell methods. The results obtained when using the Ry variational form were better than those obtained when the RyRz form was used. The choice of an optimum entangling layer was sensitively interlinked with the choice of the optimization method. The circular entangling layer was found to worsen the performance of the COBYLA method, while the full-entangling layer improved it. All four optimization methods sometimes led to an energy that corresponded to an excited state rather than the ground state. We also show that a similarity analysis of measured probabilities can provide a useful insight.

Links

MUNI/G/1596/2019, interní kód MU
Name: Development of algorithms for application of quantum computers in electronic-structure calculations in solid-state physics and chemistry (Acronym: Qubits4PhysChem)
Investor: Masaryk University, INTERDISCIPLINARY - Interdisciplinary research projects