Magnomechanical rotational Schrödinger’s cat

We propose a novel method to generate a rotational Schrödinger’s cat state made of a superposition of coherent angular oscillations (librations) of a levitated magnonic nanoparticle. By taking advantage of the magnetocrystalline anisotropy, we achieve quadratic magnon-rotational coupling. This coupling is particularly significant for small nanoscale objects. By driving the magnon with a bichromatic microwave field, we induce nonlinear rotational dissipation and parametrically excite the libration motion. This enables an efficient generation of a rotational cat state, which, under high vacuum conditions, can persist for several minutes. Our approach provides a robust and novel platform for exploring quantum superposition of rotation, which has potential applications in testing collapse models and gravitational effects on rotating quantum objects.