Response of strongly coupled fermions on classical and quantum computers

TL;DR

This paper advances the computational study of nuclear responses by developing classical and quantum algorithms, enabling more accurate modeling of complex nuclear states and revealing collective phenomena at strong coupling.

Contribution

It introduces a new classical algorithm for medium-heavy nuclei and a quantum algorithm for the Lipkin Hamiltonian, demonstrating quantum advantage in nuclear response calculations.

Findings

Classical method achieves spectroscopic accuracy for 120Sn dipole response.

Quantum algorithm accurately solves the Lipkin Hamiltonian at strong coupling.

Demonstrates quantum benefit in treating complex nuclear configurations.

Abstract

Studying the response of quantum systems is essential for gaining deeper insights into the fundamental nature of matter and its behavior in diverse physical contexts. Computation of nuclear response is critical for many applications, but its spectroscopically accurate description in medium-heavy nuclei in wide energy ranges remains particularly challenging because of the complex nature of nuclear quantum states in the high-level-density regime. Herein, we push the limits of configuration complexity in the classical computation of the nuclear response and present an algorithm with a quantum benefit for treating complex configurations. The classical computational method of approaching spectroscopic accuracy is implemented for medium-heavy nuclei and pioneered for the dipole response of 120Sn, while the quantum algorithm reaching the exact solution is realized for the Lipkin Hamiltonian to unravel the emergence of collectivity at strong coupling.