Transferência de mágnons em cadeias de Heisenberg desordenadas

Abstract

This work investigates the magnon transference throughout a disordered Heisenberg chain. We considered a model consisting of a source S, site number one, connected to a receiver R, in the last site, using Heisenberg spins. The inner sites work as a channel connecting S and R. In our model, the Heisenberg coupling between nearest-neighbor spins at the channel are random numbers. In addition, we also include an external magnetic field. In our model, the magnetic field is also random numbers uniformly distributed. The coupling between the sites S and R and the inner sites is a tunable parameter called g. Our calculations were done by considering a spin deviation at site number one and obtaining its propagation for long times. Our analyzes indicate that for g much smaller than one e for a weak disorder, it is possible to obtain quantum transfer of magnon from the first to the last site whenever the effective diagonal energies of the first and from the last site are close to the uniform mode, E = 0. We discuss in detail the necessary conditions to maintain this magnon transfer. In particular, we obtained approximately mean maximum values for disorder in internal couplings and field disturbance magnetic, which we can choose to keep good transfer.