“Superconducting hybrid nanostructures: physics and application”

Quantum interaction between acoustic resonator and superconducting qubits

Julia Zotova1, Alexey Bolgar1, Oleg Astafiev1.2

1Moscow Institute of Physics and Technology 2Royal Holloway University of London

In this work we have shown quantum interaction between an acoustic resonators and a superconducting qubit (transmon). The acoustic resonator is the resonator which works using surface acoustic wave propagation on a piezoelectric substrate. A key structure of the acoustic resonator is an inter-digital transducer (IDT), which looks like two combs which pit in inside each other. IDT can transform electric signal to mechanical surface wave and vice versa. Capacity of a transmon have shape the similar as IDT – two combs with different polarity – and it can be use as IDT too. That is why the superconducting qubit can “hear” mechanical wave. In this work we focused on low-temperature measurement results of single phonon regime of acoustic resonator: hf>>kT. Also we mention fabrication process to achieve high working frequency – 3 Ghz. It requires strong periodical structure with wide and gap between electrodes as 250 nm. Due to implement acoustic resonator-qubit we can drive a qubit via a resonator and measure qubit characteristics, and also we can use an acoustic resonator to create and implement quantum gate. Also, interaction between quantum systems via phonons is be not affected be electric or magnetic field. In addition geometric size of an acoustic resonator is much smaller, than QED devices[1,2].

Acknowledgements We would like to thank Ilya Besedin and Kirill Shulga for their help with conducting low-temperature measurement.

[1]Aref T. et al. Quantum Acoustics with Surface Acoustic Waves //Superconducting Devices in Quantum Optics. – Springer International Publishing, 2016. – С. 217-244.

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