Preserving multi-level quantum coherence by dynamical decoupling

TL;DR

This paper demonstrates experimentally that dynamical decoupling can significantly extend the coherence time of multi-level quantum systems (qudits), specifically a three-level trapped ion, paving the way for advanced quantum memory and processing.

Contribution

First experimental demonstration of dynamical decoupling applied to protect superpositions in multi-level qudits, showing scalability and potential for quantum technologies.

Findings

Prolonged coherence by up to an order of magnitude

Successful protection of three-level superpositions

Scalable approach for multi-level quantum systems

Abstract

Quantum information processing with multi-level systems (qudits) provides additional features and applications than the two-level systems. However, qudits are more prone to dephasing and dynamical decoupling for qudits has never been experimentally demonstrated. Here, as a proof-of-principle demonstration, we experimentally apply dynamical decoupling to protect superpositions with three levels of a trapped $^9\rm{Be}^+$ ion from ambient noisy magnetic field, prolonging coherence by up to approximately an order of magnitude. Our demonstration, straightforwardly scalable to more levels, may open up a path toward long coherence quantum memory, metrology and information processing with qudits.