Thermodynamic Density Matrix Renormalization Group Study of the Magnetic Susceptibility of Half-Integer Quantum Spin Chains

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 S0ex0ex=0ex0ex1/2 and S0ex0ex=0ex0ex3/2 spin chains are computed. A careful finite size analysis is made to determine the range of temperatures where the results are reliable. For the S0ex0ex=0ex0ex1/2 chain, the comparison with the exact Bethe ansatz curve shows an agreement within $1%$ down to T0ex0ex=0ex0ex0.05J.