Nonreciprocal circuit elements form an integral part of modern measurement and communication systems. Mathematically they require breaking of time-reversal symmetry, typically achieved using magnetic materials and more recently using the quantum Hall effect, parametric permittivity modulation or Josephson nonlinearities. We realized an in-situ reconfigurable, magnetic-free, on-chip circulator based on reservoir-engineered electromechanic interactions.
You can find our most recent result here: Nature Communications, reprint, SI.