Quantum-classical framework for many-fermion response and structure

TL;DR

This paper introduces a scalable quantum-classical framework utilizing the Lorentz integral transform to compute response functions and bound-state spectra of many-fermion systems, demonstrated on 9O.

Contribution

It presents a novel hybrid quantum-classical approach with practical circuit constructions for analyzing many-fermion systems, including response functions and spectra.

Findings

Successfully computed the bound-state spectrum of 9O

Accurately evaluated response functions for many-fermion systems

Demonstrated scalability and practicality of the framework

Abstract

Response functions are key observables for probing the structure and dynamics of many-body systems. We introduce and demonstrate a quantum-classical framework for computing response functions of general many-fermion systems that also provides the full bound-state spectrum. The framework employs the Lorentz integral transform and a new Hamiltonian input scheme that enables practical and scalable circuit constructions for general many-fermion Hamiltonians. Within this framework, we develop a hybrid strategy to evaluate the Lorentz integral and propose three protocols to extract response functions and bound-state structural information. As a demonstration, we apply the method to \({}^{19}\mathrm{O}\) with realistic internucleon interactions, computing both the bound-state spectrum and the response function. We envision that our approach will open new avenues for exploring the structure and dynamics of a broad class of many-body systems across diverse fields.