Mixed-state quantum transport in correlated spin networks

Quantum spin networks can be used to transport information between separated registers in a quantum-information processor. To find a practical implementation, the strict requirements of ideal models for perfect state transfer need to be relaxed, allowing for complex coupling topologies and general i...

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Bibliographic Details
Main Authors: Ajoy, Ashok, Cappellaro, Paola
Other Authors: Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Format: Article
Language:en_US
Published: American Physical Society 2012
Online Access:http://hdl.handle.net/1721.1/71723
https://orcid.org/0000-0003-0544-5263
https://orcid.org/0000-0003-3207-594X
Description
Summary:Quantum spin networks can be used to transport information between separated registers in a quantum-information processor. To find a practical implementation, the strict requirements of ideal models for perfect state transfer need to be relaxed, allowing for complex coupling topologies and general initial states. Here we analyze transport in complex quantum spin networks in the maximally mixed state and derive explicit conditions that should be satisfied by propagators for perfect state transport. Using a description of the transport process as a quantum walk over the network, we show that it is necessary to phase-correlate the transport processes occurring along all the possible paths in the network. We provide a Hamiltonian that achieves this correlation and use it in a constructive method to derive engineered couplings for perfect transport in complicated network topologies.