This current of heat creates a separation of electron spins that then diffuse through the Cu heat sink and affect the magnetization of
a second ferromagnetic layer, CoFeB, causing the magnetization to tilt and then precess.
The «wormhole» in this experiment is a sphere made of different layers: an external layer with a
ferromagnetic surface, a
second inner layer, made of superconducting material, and a
ferromagnetic sheet rolled into a cylinder that crosses the sphere from one end to the other.