Thermodynamic Density Matrix renormalization Group Study of the Magnetic Susceptibility of Half-integer Quantum Spin Chains

TL;DR

This paper demonstrates how the density matrix renormalization group method can be adapted to calculate thermodynamic properties, specifically magnetic susceptibility, of quantum spin chains, with high accuracy at low temperatures.

Contribution

It introduces an adaptation of White's DMRG technique for thermodynamic calculations and validates it against exact solutions for spin chains.

Findings

Accurate susceptibility calculations for S=1/2 and S=3/2 chains

Agreement within 1% with Bethe ansatz for S=1/2 chain at low T

Finite size analysis ensures reliability of results

Abstract

It is shown that White's density matrix renormalization group technique can be adapted to obtain thermodynamic quantities. As an illustration, the magnetic susceptibility of Heisenberg S=1/2 and S=3/2 spin chains are computed. A careful finite size analysis is made to determine the range of temperatures where the results are reliable. For the S=1/2 chain, the comparison with the exact Bethe ansatz curve shows an agreement within 1% down to T=0.05J.