Eur. Phys. J. B (2013) 86: 507
https://doi.org/10.1140/epjb/e2013-40684-y

Regular Article

Spinon and η-spinon correlation functions of the Hubbard chain

¹ Centro de Física das Interacções Fundamentais, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
² Beijing Computational Science Research Center, Beijing 100084, P.R. China
³ Department of Physics and Institute of Theoretical Physics, The Chinese University of Hong Kong, Hong Kong, P.R. China
⁴ Centre and Department of Physics, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal
⁵ Institut für Theoretische Physik III, Universität Stuttgart, 70550 Stuttgart, Germany

^a e-mail: pdss@cfif.ist.utl.pt

Received: 19 July 2013
Received in final form: 30 October 2013
Published online: 16 December 2013

Abstract

We calculate real-space static correlation functions of spin and charge degrees of freedom of the one-dimensional Hubbard model that are described by operators related to singly occupied sites with spin up or spin down (spinons) and unoccupied or doubly occupied sites (η-spinons). The spatial decay of their correlation functions is determined using density matrix renormalization group results. The nature and spatial extent of the correlations between two sites on the Hubbard chain is studied using the eigenstates and eigenvalues of the two-site reduced density matrix. The results show that the spinon-spinon correlation functions decay algebraically and the η-spinon correlation functions decay exponentially, both in the half-filling and metallic phases. The results provide evidence that these degrees of freedom are organized in boundstates in the interacting system.