Preserving multilevel quantum coherence by dynamical decoupling

Quantum information processing with multilevel 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 Be-9(+) 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.

Automated summary

A proof-of-principle experiment demonstrates the use of dynamical decoupling to protect superpositions in multilevel systems (qudits) from environmental magnetic field interference, significantly prolonging coherence. This experiment opens up possibilities for long coherence quantum memory, metrology, and information processing with qudits.