Entanglement in Finite Quantum Systems Under Twisted Boundary Conditions

Author(s)

Zawadzki, Krissia ^[1] ; D'Amico, Irene ^[2] ; Oliveira, Luiz N. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, Dept Fis & Ciencia Interdisciplinar, Caixa Postal 369, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ York, Dept Phys, York YO10 5DD, N Yorkshire - England

• Document type: Journal article
• Source: Brazilian Journal of Physics; v. 48, n. 5, p. 451-466, OCT 2018.
• Web of Science Citations: 0

Abstract

In a recent publication, we have discussed the effects of boundary conditions in finite quantum systems and their connection with symmetries. Focusing on the one-dimensional Hubbard Hamiltonian under twisted boundary conditions, we have shown that properties, such as the ground-state and gap energies, converge faster to the thermodynamical limit (L -> infinity) if a special torsion Theta{*} is adjusted to ensure particle-hole symmetry. Complementary to the previous research, the present paper extends our analysis to a key quantity for understanding correlations in many-body systems: the entanglement. Specifically, we investigate the average single-site entanglement (S-j) as a function of the coupling U/t in Hubbard chains with up to L = 8 sites and further examine the dependence of the per-site ground-state epsilon(0) on the torsion Theta in different coupling regimes. We discuss the scaling of epsilon(0) and (S-j) under Theta{*} and analyze their convergence to Bethe Ansatz solution of the infinite Hubbard Hamiltonian. Additionally, we describe the exact diagonalization procedure used in our numerical calculations and show analytical calculations for the case study of a trimer. (AU)

• FAPESP's process: 12/02702-0 - Magnetic relaxation in dilute magnetic alloys
• Grantee: Krissia de Zawadzki
• Support Opportunities: Scholarships in Brazil - Master