Demonstration of quadrature nonreciprocity

In a study published in Nature Physics today, we report a phenomenon of unidirectional signal transmission that challenges conventional wisdom about nonreciprocity: Instead of relying on magnetic fields that break time-reversal symmetry, it exploits interference between parametric amplification and regular mode coupling to achieve a type of transmission that we dub quadrature nonrecprocity. We demonstrate this experimentally in a nano-optomechanical system. Congratulations to (former) group members Jesse Slim and Javier del Pino, and thanks to our wonderful collaborators Clara Wanjura, Matteo Brunelli, and Andreas Nunnenkamp. See our press release and the paper itself.