Density matrix renormalization group approach to two-fluid open many-fermion systems

TL;DR

This paper extends the DMRG method to complex-symmetric Hamiltonians for two-fluid open many-fermion systems, enabling efficient analysis of weakly-bound and unbound nuclear systems in the Gamow Shell Model.

Contribution

The authors develop a DMRG approach tailored for complex-symmetric Hamiltonians in the GSM, allowing treatment of large, complex nuclear systems beyond direct diagonalization.

Findings

Identified conditions for accurate ground state eigenvalues using GSM+DMRG.

Compared different truncation schemes within the DMRG framework.

Demonstrated the method on three- and four-nucleon systems.

Abstract

We have extended the density matrix renormalization group (DMRG) approach to two-fluid open many-fermion systems governed by complex-symmetric Hamiltonians. The applications are carried out for three- and four-nucleon (proton-neutron) systems within the Gamow Shell Model (GSM) in the complex-energy plane. We study necessary and sufficient conditions for the GSM+DMRG method to yield the correct ground state eigenvalue and discuss different truncation schemes within DMRG. The proposed approach will enable configuration interaction studies of weakly-bound and unbound strongly interacting complex systems which, because of a prohibitively large size of Fock space, cannot be treated by means of the direct diagonalization.