Broadband reconfigurable logic gates in phonon waveguides
  The high-quality-factor mechanical resonator in electromechanical systems has facilitated dynamic control of phonons via parametric nonlinear processes and paved the development of mechanical logic-elements. However the resonating element with a narrow bandwidth limits the resultant operation speeds as well as constraining the availability of nonlinear phenomena to a narrow spectral range. To overcome these drawbacks we have developed phonon waveguides in which the mechanical analogue of four-wave-mixing is demonstrated that enables the frequency of phonon waves to be converted over 1 MHz. We harness this platform to execute multiple binary mechanical logic gates in parallel, via frequency division multiplexing in a two-octave-wide phonon transmission band, where each gate can be independently reconfigured. The fidelity of the binary gates is verified via temporal measurements yielding eye diagrams which confirm the availability of high speed logic operations. The phonon waveguide architecture thus offers the broadband functionality that is essential to realising mechanical signal processors. 
Daiki Hatanaka, Tom Darras, Imran Mahboob, Koji Onomitsu and Hiroshi   Yamaguchi
cond-mat.mes-hall