Quantum hardware that processes information in N-level systems (qudits) as opposed to the conventional binary (qubit) encoding, has significant advantages. A qudit processor poses a resource-efficient way to increase the available Hilbert space and strongly reduce the number of required entangling gates (that are typically the most difficult to perform) for a given algorithm. To capitalize on the full potential of the higher-energy states in the transmon circuit, we are (1) designing circuits optimized for qudit coupling and readout, (2) employing quantum control techniques, inspired NMR and quantum optics, to perform high-fidelity single-and mulitple-qudit gates, and (3) exploring quantum computing, simulation -, and sensing protocols where qudits have advantage of qubits.

Relevant Publications

Quantum Information Scrambling in a Superconducting Qutrit Processor
M.S. Blok*, V. V. Ramasesh*, T. Schuster, K. O’Brien, J.M. Kreikebaum, D. Dahlen, A. Morvan, B. Yoshida, N. Y. Yao, I. Siddiqi.
Phys. Rev. X  11, 021010 (2021)| Arxiv:2003.03307

Qutrit randomized benchmarking
A. Morvan, V. V. Ramasesh, M. S. Blok, J.M. Kreikebaum, K. O’Brien, L. Chen, B. K. Mitchell, R. K. Naik, D. I. Santiago, I. Siddiqi
Phys. Rev. Lett. 126, 210504 (2021) |Arxiv:2008.09134