1 research outputs found
Real-time energy dynamics in spin-1/2 Heisenberg chains
We study the real-time dynamics of the local energy density in the spin-1/2
XXZ chain starting from initial states with an inhomogeneous profile of bond
energies. Numerical simulations of the dynamics of the initial states are
carried out using the adaptive time-dependent density matrix renormalization
group method. We analyze the time dependence of the spatial variance associated
with the local energy density to classify the dynamics as either ballistic or
diffusive. Our results are consistent with ballistic behavior both in the
massless and the massive phase. We also study the same problem within Luttinger
Liquid theory and obtain that energy wave-packets propagate with the sound
velocity. We recover this behavior in our numerical simulations in the limit of
very weakly perturbed initial states.Comment: 15 pages, 21 figures, version as published, minor stylistic change