Acoustic coupling between magnon Bose–Einstein condensates in yttrium iron garnet films

The excitation of a magnon Bose–Einstein condensate in an yttrium iron garnet film due to acoustic coupling with the condensate in the second sample is experimentally studied. A nonlinear nature of this excitation is demonstrated. The formation of a phonon Bose–Einstein condensate in the substrate is assumed. This experiment opens the possibility of creating qubits based on acoustically interacting Bose–Einstein condensates.