Abstract:
Arrays of transmon qubits coupled to a λ/2 superconducting coplanar waveguide resonator have been studied by microwave spectroscopy. The emergence of a collective mode has been discovered for a cluster of N>5 qubits, whose coupling constant to the electromagnetic field in the resonator is √N times greater compared to a single qubit. In addition, the emergence of collective multiphoton transitions exciting higher levels of a qubit cluster has been demonstrated and the interaction of an individual qubit with such a cluster has been investigated.
Citation:
K. V. Shulga, P. Yang, G. P. Fedorov, M. V. Fistul, M. Weides, A. V. Ustinov, “Observation of a collective mode of an array of transmon qubits”, Pis'ma v Zh. Èksper. Teoret. Fiz., 105:1 (2017), 38–42; JETP Letters, 105:1 (2017), 47–50