Month: January 2012

Spin chains for robust state transfer: Modified boundary couplings versus completely engineered chains | Phys. Rev. A 85, 012318 (2012)

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Analia Zwick, Gonzalo A. Álvarez, Joachim Stolze, and Omar Osenda

Received 9 November 2011; published 19 January 2012

Quantum state transfer in the presence of static disorder and noise is one of the main challenges in building quantum computers. We compare the quantum state transfer properties for two classes of qubit chains under the influence of static disorder. In fully engineered chains all nearest-neighbor couplings are tuned in such a way that a single-qubit state can be transferred perfectly between the ends of the chain, while in chains with modified boundaries only the two couplings between the transmitting and receiving qubits and the remainder of the chain can be optimized. We study how the disorder in the couplings affects the state transfer fidelity depending on the disorder model and strength as well as the chain type and length. We show that the desired level of fidelity and transfer time are important factors in designing a chain. In particular we demonstrate that transfer efficiency comparable or better than that of the most robust engineered systems can also be reached in chains with modified boundaries without the demanding engineering of a large number of couplings.

©2012 American Physical Society

via Phys. Rev. A 85, 012318 (2012): Spin chains for robust state transfer: Modified boundary couplings versus completely engineered chains.

Contour lines of the averaged transfer fidelity F = 0.9 for fully engineered PST systems (closed symbols) and boundary-controlled α-OST systems. To the left of the symbols the transfer fidelity F > 0.9 for every system.
Contour lines of the averaged transfer fidelity F = 0.9 for fully engineered PST systems (closed symbols) and boundary-controlled α-OST systems. To the left of the symbols the transfer fidelity F > 0.9 for every system.