Controllable coupling between a nanomechanical resonator and a coplanar-waveguide resonator via a superconducting flux qubit

Abstract

We study a tripartite quantum system consisting of a coplanar-waveguide (CPW) resonator and a nanomechanical resonator (NAMR) connected by a flux qubit, where the flux qubit has a large detuning from both resonators. By a unitray transformation and a second-order approximation, we obtain a strong and controllable (i.e., magnetic-field-dependent) effective coupling between the NAMR and the CPW resonator. Due to the strong coupling, vacuum Rabi splitting can be observed from the voltage-fluctuation spectrum of the CPW resonator. We further study the properties of single photon transport as inferred from the reflectance or equivalently the transmittance. We show that the reflectance and the corresponding phase shift spectra both exhibit doublet of narrow spectral features due to vacuum Rabi splitting. By tuning the external magnetic field, the reflectance and the phase shift can be varied from 0 to 1 and $-\pi$ to $\pi$, respectively. The results indicate that this hybrid quantum system can act as a quantum router.

8 pages, 6 figures

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Cited by in corpus (7)

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• Engineering Photon Delocalization in a Rabi Dimer with a Dissipative Bath
• Novel hermetically sealed device to realize unconventional phonon blockade at near-micron dimensions and milli Kelvin temperatures
• Multiphoton controllable transport between remote resonators
• Routing single photons with quantum emitters coupled to nanostructures
• Nonreciprocal routing induced by chirality in an atom-dimer waveguide-QED system