Displacemon Electromechanics: How to Detect Quantum Interference in a Nanomechanical Resonator

• Main Authors: K. E. Khosla, M. R. Vanner, N. Ares, E. A. Laird
• Format: Article
• Language: English
• Published: American Physical Society 2018-05-01
• Series: Physical Review X
• Online Access: http://doi.org/10.1103/PhysRevX.8.021052

We introduce the “displacemon” electromechanical architecture that comprises a vibrating nanobeam, e.g., a carbon nanotube, flux coupled to a superconducting qubit. This platform can achieve strong and even ultrastrong coupling, enabling a variety of quantum protocols. We use this system to describe a protocol for generating and measuring quantum interference between trajectories of a nanomechanical resonator. The scheme uses a sequence of qubit manipulations and measurements to cool the resonator, to apply two effective diffraction gratings, and then to measure the resulting interference pattern. We demonstrate the feasibility of generating a spatially distinct quantum superposition state of motion containing more than 10^{6} nucleons using a vibrating nanotube acting as a junction in this new superconducting qubit configuration.