Charge and spin dynamics of the Hubbard chains

TL;DR

This paper investigates the charge and spin dynamics in Hubbard chains using advanced numerical methods, revealing how these excitations depend on interaction strength and electron filling, with implications for understanding correlated electron systems.

Contribution

The study applies density matrix renormalization group and recursion techniques to accurately compute local charge and spin correlations in Hubbard chains, highlighting their distinct low-energy behaviors.

Findings

Charge bandwidth proportional to hopping parameter t

Spin bandwidth proportional to exchange interaction J

Charge and spin correlations differ at low energies

Abstract

We calculate the local correlation functions of charge and spin for the one-chain and two-chain Hubbard model using the density matrix renormalization group method and the recursion technique. Keeping only finite number of states we get good accuracy for the low energy excitations. We study the charge and spin gaps, bandwidths and weights of the spectra for various values of the on-site Coulomb interaction U and the electron filling. In the low energy part, the local correlation functions are different for the charge and spin. The bandwidths are proportional to t for the charge and J for the spin, respectively.