Quantum simulations employing connected moments expansions

TL;DR

This paper introduces a quantum computing method using connected moment expansions that reduces circuit depth and CNOT gates, demonstrating robustness and accuracy across molecular and condensed matter models.

Contribution

The authors develop a novel quantum approach employing finite-order connected moment expansions with efficient initial state preparation, applicable to complex many-body systems.

Findings

Accurately models H2 molecule potential energy surface.

Performs well on the Anderson model across correlation strengths.

Maintains agreement with exact solutions in challenging regimes.

Abstract

Further advancement of quantum computing (QC) is contingent on enabling many-body models that avoid deep circuits and excessive use of CNOT gates. To this end, we develop a QC approach employing finite-order connected moment expansions (CMX) and affordable procedures for initial state preparation. We demonstrate the performance of our approach employing several quantum variants of CMX through the classical emulations on the H2 molecule potential energy surface and the Anderson model with a broad range of correlation strength. The results show that our approach is robust and flexible. Good agreements with exact solutions can be maintained even at the dissociation and strong correlation limits.