English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In this study, we utilize the many-body expansion (MBE) framework todecompose electronic structures into fragments by incrementing the virtualorbitals. Our work aims to accurately solve the ground and excited stateenergies of each fragment using the variational quantum eigensolver anddeflation algorithms. Although our approach is primarily based on unitarycoupled cluster singles and doubles (UCCSD) and a generalization thereof, wealso introduce modifications and approximations to conserve quantum resourcesin MBE by partially generalizing the UCCSD operator and neglecting therelaxation of the reference states. As a proof of concept, we investigate thepotential energy surfaces for the bond-breaking processes of the ground stateof two molecules ($\rm H_2O$ and $\rm N_2$) and calculate the ground andexcited state energies of three molecules (LiH, CH$^+$, and $\rm H_2O$). Theresults demonstrate that our approach can, in principle, provide reliabledescriptions in all tests, including strongly correlated systems, whenappropriate approximations are chosen. Additionally, we perform modelsimulations to investigate the impact of shot noise on the total MBE energy andshow that precise energy estimation is crucial for lower-order MBE fragments.

Many-Body-Expansion Based on Variational Quantum Eigensolver and Deflation for Dynamical Correlation