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Coupling two distant double quantum dots to a microwave resonator

With recent advances in the circuit quantum electrodynamics (cQED) architecture, hybrid systems that couple nano-devices to microwave resonators have been developing rapidly. Here we report an experimental demonstration of two graphene double quantum dots (DQDs) coupled over a distance of up to 60 μm, through a microwave resonator. We jointly measure the two DQDs' coupling to the resonator, which causes a nonlinear response in the resonator reflection amplitude in the vicinity of the degeneracy points of the two DQDs. This phenomenon is explained by the Tavis-Cummings (T-C) mode. We further characterize this nonlocal coupling by measuring the correlation between the DC currents in the two DQDs. This correlation is observed to be strongly dependent on the average photon number in the resonator. Our results explore T-C physics in electronic transport, and also contribute to the study of nonlocal transport and future implementations of remote electronic entanglement.