Pretty good state transfer of entangled states through quantum spin chains
New Journal of Physics Vol. 16, Nº , pp. 2 - 12, December, 2014.
ISSN (print): 1367-2630
Journal Impact Factor: 3,558 (in 2014)
Digital Object Identifier: 10.1088/1367-2630/16/12/123003
The XX model with uniform couplings represents the most natural choice for quantum state transfer through spin chains. Given that it has long been established that single-qubit states cannot be transferred with perfect fidelity in this model, the notion of pretty good state transfer has been recently introduced as a relaxation of the constraints on fidelity. In this paper, we study the transfer of multi-qubit entangled and unentangled states through unmodulated spin chains, and we prove that it is possible to have pretty good state transfer of any multi-particle state. This significantly generalizes the previous results on single-qubit state transfer and opens the way to using uniformly coupled spin chains as short-distance quantum channels for the transfer of arbitrary states of any dimension. Our results could be tested with current technology.