Autonomous quantum error correction with application to quantum metrology

Christine Muschik
Institute für Quantenoptik und Quanteninformation, Universität Innsbruck

The quest to find viable strategies for quantum error correction is of fundamental interest and an essential prerequisite for the development of quantum technologies. I will present a new quantum error correction scheme that keeps a qubit alive by coupling it to an engineered environment that protects it against spin- or phase flips. Our scheme uses always-on couplings that run continuously in time and operates in a fully autonomous fashion without the need to perform measurements or feedback operations on the system. The correction of errors takes place entirely at the microscopic level through a build-in feedback mechanism. Our dissipative error correction scheme can be implemented in a system of trapped ions and can be used for improving high precision sensing. We show that the enhanced coherence time that results from the coupling to the engineered environment translates into a significantly enhanced precision for measuring weak fields and will enable proof-of-principle experiments with ions that take the study of dissipative methods for quantum information processing tasks to a new level beyond state preparation. In a broader context, this work constitutes a stepping stone towards the paradigm of self-correcting quantum information processing.