Massachusetts Institute of Technology Cambridge United States
The goal of the project Modular Paradigm for Scalable Quantum Information was to address some of the challenges facing the field of quantum information science QIS. The requirements to reliably control a scalable quantum system while staving off decoherence pose a contradiction, as fast control implies a strong coupling to a controlling external system, but this entails an undesired interaction with the environment, leading to decoherence. We thus studied a new paradigm for QIS, given by smaller building blocks composed of a quantum register and a controller that are connected by spin wires. Among the project accomplishments are novel strategies for time-optimal control via a quantum controller, a quantum feedback scheme where the controller is fully quantum, and the first implementation of quantum information transport in a mixed-state spin chain.