A microwave-activated controlled-phase gate between a transmon and a fluxonium
ORAL
Abstract
In the quest for high qubit coherence, fluxonium qubits have emerged as promising candidates for
storing quantum information, reaching 1 ms coherence times. On the other hand, large
superconducting qubit devices based on transmon qubits have been built due to the relative
simplicity of the circuit and the ability to perform fast two-qubit gates compared to their coherence
times. We here analyze how two-qubit gates between a transmon and a fluxonium can be realized in
a possible hybrid architecture. The observation that the typical transmon frequencies are at least one
order of magnitude larger than those of the fluxonia leads immediately to the following question:
how can we couple qubits with such different frequencies? We show that this is possible by
microwave-activating the coupling by virtually exciting the fluxonium to its higher levels. In
particular, we consider a microwave-driven controlled-phase gate between capacitively-coupled
transmon and fluxonium qubits, similar to the approach proposed in [Ficheux et al, Phys. Rev. X 11,
021026, (2021)] for two fluxonia. We perform simulations of the gate, including relaxation and
dephasing noise, and show that the gate can be realized with high fidelity while allowing for low
leakage and low residual ZZ coupling.
storing quantum information, reaching 1 ms coherence times. On the other hand, large
superconducting qubit devices based on transmon qubits have been built due to the relative
simplicity of the circuit and the ability to perform fast two-qubit gates compared to their coherence
times. We here analyze how two-qubit gates between a transmon and a fluxonium can be realized in
a possible hybrid architecture. The observation that the typical transmon frequencies are at least one
order of magnitude larger than those of the fluxonia leads immediately to the following question:
how can we couple qubits with such different frequencies? We show that this is possible by
microwave-activating the coupling by virtually exciting the fluxonium to its higher levels. In
particular, we consider a microwave-driven controlled-phase gate between capacitively-coupled
transmon and fluxonium qubits, similar to the approach proposed in [Ficheux et al, Phys. Rev. X 11,
021026, (2021)] for two fluxonia. We perform simulations of the gate, including relaxation and
dephasing noise, and show that the gate can be realized with high fidelity while allowing for low
leakage and low residual ZZ coupling.
*B.M.V., N.J. and B.T. are supported by QuTech NWO funding 2020-2024 – Part I "Fundamental Research" with project number 601.QT.001-1. A. C. acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy – Cluster of Excellence Matter and Light for Quantum Computing (ML4Q) EXC 2004/1 – 390534769 and from the German Federal Ministry of Education and Research in the funding program "quantum technologies – from basic research to market" (contract number 13N15585). C. K. A. would like to acknowledge support from NWO and Qutech.
–
Presenters
-
Alessandro Ciani
- Forschungszentrum Jülich