Implementing High-fidelity Quantum Gates in Multi-level Trapped Ions

Summary

The scalability of quantum processors is limited by current error rates for single-qubit gates. By encoding more than a single bit of information within a single ion, multi-level “qudits” offer a promising method of increasing the information density within a quantum processor, and therefore minimizing the number of gates and associated error rates. In this project we seek to improve the capabilities of trapped ion quantum processors, implementing all of the basic tools required to perform quantum information processing with multi-level qudits. To-date there have been few experimental efforts directed towards this area and many of the basic operations – such as reliably distinguishing among all possible basis states in a single-shot measurement or performing deterministic entangling gates – have not yet been demonstrated. In this project, we will design and construct a laser system that will be used to perform coherent operations, and to implement and characterize high-fidelity single-qudit gates. These will form some of the world’s first laboratory demonstrations of quantum computing with multi-level qudits. Because our approach will allow more information to be encoded with fewer qudits, and folds some of the complexity of a given algorithm into the non-entangling operations, there is reason to believe that the use of multi-level qudits could bring dramatic improvements to the scalability of quantum processors.