Journal of the Physical Society of Japan
Twist Method for Quantum Ground-State Problems and its Application to Antiferromagnetic Heisenberg Chains with Competing Interactions
Kiyomi Okamoto, Yohtaro Ueno
Abstract
We present a quantum version of the twist method which has been developed for classical systems. A finite size scaling form for the excess ground state energy is derived and tested for an S =1/2 antiferromagnetic Heisenberg chain with next nearest neighbor interactions: H = J ∑( S j · S j +1 + α S j · S j +2 ) with J >0 and α>0. Using an exact diagonalization method, we obtain the critical value \(\alpha_{c} \cong 0.246\) of the fluid-dimer transition, which is very close to the reliable value recently obtained by Okamoto and Nomura (Phys. Lett. A 169 (1992) 433).