We investigate a non-adiabatic holonomic operation that enables us to entangle two fixed-frequency superconducting transmon qubits attached to a common bus resonator. Two coherent microwave tones are applied simultaneously to the two qubits and drive transitions between the first excited resonator state and the second excited state of each qubit. The cyclic evolution within this effective 3-level Λ-system gives rise to a holonomic operation entangling the two qubits. Two-qubit states with 95\% fidelity, limited mainly by charge-noise of the current device, are created within 213ns. This scheme is a step toward implementing a SWAP-type gate directly in an all-microwave controlled hardware platform. By extending the available set of two-qubit operations in the fixed-frequency qubit architecture, the proposed scheme may find applications in near-term quantum applications using variational algorithms to efficiently create problem-specific trial states.
@article{arxiv.1804.04900,
title = {Entanglement generation in superconducting qubits using holonomic operations},
author = {Daniel J. Egger and Marc Ganzhorn and Gian Salis and Andreas Fuhrer and Peter Mueller and Panagiotis Kl. Barkoutsos and Nikolaj Moll and Ivano Tavernelli and Stefan Filipp},
journal= {arXiv preprint arXiv:1804.04900},
year = {2019}
}