Young Investigator Program: Modular Paradigm for Scalable Quantum Information

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