Towards quantum computing for high-energy excited states in molecular systems: quantum phase estimations of core-level states

TL;DR

This paper investigates the application of quantum phase estimation (QPE) for calculating high-energy core-level excited states in molecules, comparing its effectiveness with existing many-body methods and discussing its potential for challenging shake-up states.

Contribution

It demonstrates the feasibility of using quantum phase estimation for high-energy excited states and compares its performance with traditional many-body techniques.

Findings

QPE can identify challenging shake-up states.

QPE shows promising accuracy for core-level states.

Comparison with high-accuracy methods highlights strengths and limitations.

Abstract

This paper explores the utility of the quantum phase estimation (QPE) in calculating high-energy excited states characterized by promotions of electrons occupying inner energy shells. These states have been intensively studied over the last few decades especially in supporting the experimental effort at light sources. Results obtained with the QPE are compared with various high-accuracy many-body techniques developed to describe core-level states. The feasibility of the quantum phase estimator in identifying classes of challenging shake-up states characterized by the presence of higher-order excitation effects is also discussed.