Optimal quantum state transfer in noisy qubit-channels

ANALIA ZWICK, GUY BENSKY, GONZALO ALVAREZ, GERSHON KURIZKI

Conferencia; Quantum Information; 2013

Contributed Talk: Quantum communication between remote registers is one of the key building blocks for building quantum computers. Spin chains can act as quantum channels for the transmission of information with an accuracy that depends of the interaction between the spins. Perfect state transfer channels can be obtained by accurately engineering each of those interactions to well specified values. In the eagerness to avoid such demanding and challenging requirement, we show that, by tailoring only the boundary qubit interactions of the simplest homogeneous channel, a high fidelity transfer can be achieved. The method work even for room temperature and it is also robust against static perturbations. We find an optimal regime for fast transfer and we observe a power-law scaling of the fidelity depending on the chain length and the disorder strength. In general, improving the fidelity and/or the robustness of the channel requires longer times for transferring the information. By adding also dynamical control on the boundary interactions, we can increase by orders of magnitude the information transfer speed and the fidelity while keeping a comparable robustness against perturbations. This is done by using a general optimization method for dynamical control of quantum open systems.