arXiv:0901.2342 · Physical Review B
Spectral functions in one-dimensional quantum systems at finite temperature using the density matrix renormalization group
Thomas Barthel, Ulrich Schollwöck, Steven R. White
Abstract
We present time-dependent density matrix renormalization group simulations $(t\text{-DMRG})$ at finite temperatures. It is demonstrated how a combination of finite-temperature $t\text{-DMRG}$ and time-series prediction allows for an easy and very accurate calculation of spectral functions in one-dimensional quantum systems, irrespective of their statistics for arbitrary temperatures. This is illustrated with spin structure factors of $XX$ and $XXX$ spin-$\frac{1}{2}$ chains. For the $XX$ model we can compare against an exact solution, and for the $XXX$ model (Heisenberg antiferromagnet) against a Bethe ansatz solution and quantum Monte Carlo data.