Entangling Interactions Between Artificial Atoms Mediated by a Multimode Left-Handed Superconducting Ring Resonator

PRX Quantum, vol. 5

Abstract

Superconducting metamaterial transmission lines implemented with lumped circuit elements can exhibit left-handed dispersion, where the group and phase velocity have opposite sign, in a frequency range relevant for superconducting artificial atoms. Forming such a metamaterial transmission line into a ring and coupling it to qubits at different points around the ring results in a multimode bus resonator with a compact footprint. Using flux-tunable qubits, we characterize and theoretically model the variation in the coupling strength between the two qubits and each of the ring-resonator modes. Although the qubits have negligible direct coupling between them, their interactions with the multimode ring resonator result in both a transverse exchange coupling and a higher-order ZZ interaction between the qubits. As we vary the detuning between the qubits and their frequency relative to the ring-resonator modes, we observe significant variations in both of these interqubit interactions, including zero crossings and changes of sign. The ability to modulate interaction terms such as the ZZ scale between zero and large values for small changes in qubit frequency provides a promising pathway for implementing entangling gates in a system capable of hosting many qubits. Published by the American Physical Society 2024

Authors 8

1. T. McBroom-Carroll

   Syracuse University

   Affiliation as printed

   Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA

2. A. Schlabes Aachen Institute for Quantum Information

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Institute for Quantum Information, RWTH Aachen University, Aachen D-52056, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technologies, Germany

   Peter Grünberg Institute (PGI-2), Forschungszentrum Jülich, Jülich 52428, Germany

3. Jaseung Ku

   Syracuse University

   Affiliation as printed

   Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA

4. B. Cole

   Syracuse University

   Affiliation as printed

   Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA

5. Sagar Indrajeet

   Syracuse University

   Affiliation as printed

   Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA

6. Matthew LaHaye

   U.S. Air Force Research Laboratory Information Directorate · Syracuse University

   Affiliation as printed

   Air Force Research Laboratory, Information Directorate, Rome, New York 13441, USA

   Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA

7. Mohammad H. Ansari Aachen Institute for Quantum Information

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Institute for Quantum Information, RWTH Aachen University, Aachen D-52056, Germany

   Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technologies, Germany

   Peter Grünberg Institute (PGI-2), Forschungszentrum Jülich, Jülich 52428, Germany

8. B. L. T. Plourde

   Syracuse University

   Affiliation as printed

   Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA