Systematic many-fermion Hamiltonian input scheme and spectral calculations on quantum computers

TL;DR

This paper introduces a new input scheme for many-fermion Hamiltonians that respects fermionic properties and symmetries, enabling efficient spectral calculations on quantum computers with demonstrated applications to calcium isotopes.

Contribution

The paper proposes a novel input scheme for second-quantized Hamiltonians that incorporates fermionic relations and symmetries, facilitating quantum spectral calculations.

Findings

Designed explicit quantum circuits with gate cost analysis.

Successfully computed low-lying spectra of calcium isotopes.

Provided a hybrid quantum-classical framework for fermionic systems.

Abstract

We present a novel input scheme for general second-quantized Hamiltonians of relativistic or non-relativistic many-fermion systems. This input scheme incorporates the fermionic anticommutation relations, particle number variations, and respects the symmetries of the Hamiltonian. Based on our input scheme, we propose a hybrid quantum-classical framework for spectral calculations on future quantum hardwares. We provide explicit circuit designs and the associated gate cost. We demonstrate our hybrid framework by solving the low-lying spectra of ${^{42}}$Ca and ${^{46}}$Ca. Our input scheme provides new pathways to solving the spectra and dynamics of the relativistic and nonrelativistic many-fermion systems via first-principles approaches.