Abstract
Anderson localisation is an important phenomenon arising in many areas of physics, and here we explore it in the context of quantum information devices. Finite dimensional spin chains have been demonstrated to be important devices for quantum information transport, and in particular can be engineered to allow for "perfect state transfer" (PST). Here we present extensive investigations of disordered PST spin chains, demonstrating spatial localisation and transport retardation effects, and relate these effects to conventional Anderson localisation. We provide thresholds for Anderson localisation in these finite quantum information systems for both the spatial and the transport domains. Finally, we consider the effect of disorder on the eigenstate and energy spectrum of our Hamiltonian, where results support our conclusions on the presence of Anderson localisation.
Highlights
Anderson localisation was predicted in 1958 [1], to explain experimental findings of anomalously long relaxation of spins in semiconductors, and linked to the metalinsulator transition
In this paper we have investigated the phenomenon of localisation in one-dimensional perfect state transfer” (PST) spin chains
For low disorder these chains are known to exhibit some robustness in their transport properties, which is why they are of interest for quantum information transport
Summary
Anderson localisation was predicted in 1958 [1], to explain experimental findings of anomalously long relaxation of spins in semiconductors, and linked to the metalinsulator transition. We focus on one dimensional finite spin chains, which have been set up for “perfect state transfer” (PST) [14,15,16] In recent years this type of spin chain has acquired growing importance within the field of quantum information processing, as a means of efficiently transferring information [17,18], or for creating and distributing entanglement [19] within a solid state-based quantum processor or computer. Due to their properties, PST spin chains may display, for a given level of disorder and within the same chain, different regimes of transport and localisation behaviour (including Anderson localisation) This demonstrates that PST spin chains form an interesting new class of systems in which to study localisation phenomena
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