Phonon phase shifter

The goal of this project is to dynamically control the propagation of traveling phonons in silicon-based waveguide devices and thereby realize a phonon phase shifter [1]. In combination with recently developed phonon waveguides [2,3] and a beamsplitter[4], we thereby complete the toolbox needed for performing linear quantum operations using phonons - analog to linear optical quantum computing [5]. With this toolbox, we obtain full coherent control over traveling acoustic modes on-chip, which can be used to distribute quantum information between various quantum systems and therefore act as a transducer for hybrid quantum systems. Our approach relies on manipulating the phononic dispersion relation by introducing strain to the suspended phononic waveguides. To experimentally induce the required strain in the waveguide, we implement piezoelectric elements on both sides of the phononic waveguides. Our simulations predict that applying a voltage of ±50V to a 300 µm-long waveguide will induce a phase shift of ±π/2. Furthermore, we present the design, fabrication, and initial characterization of our devices.

[1] J. C. Taylor, E. Chatterjee, W. F. Kindel, D. Soh, M. Eichenfield, Npj Quantum Inf. 8(1), 19 (2022).

[2] A. Zivari, R. Stockill, N. Fiaschi, S. Gröblacher, Nat. Phys. 18, 789–793 (2022).

[3] A. Zivari, N. Fiaschi, R. Burgwal, E. Verhagen, R. Stockill, S. Gröblacher, Sci. Adv. 8(46), eadd2811 (2022).

[4] A. Zivari, N. Fiaschi, L. Scarpelli, M. Jansen, R. Burgwal, E. Verhagen, S. Gröblacher, arXiv preprint arXiv:2312.04414 (2023).

[5] E. Knill, R. Laflamme, and G. J. Milburn, , Nature 409, 46 (2001).