Skyrmion burst and multiple quantum walk in thin ferromagnetic films

We propose a new type of quantum walk in thin ferromagnetic films. A giant Skyrmion collapses to a singular point in a thin ferromagnetic film, emitting spin waves, when external magnetic field is increased beyond the critical one. After the collapse the remnant is a quantum walker carrying spin S  . We determine its time evolution and show the diffusion process is a continuous-time quantum walk. We also analyze an interference of two quantum walkers after two Skyrmion bursts. The system presents a new type of quantum walk for S>1/2S>1/2, where a quantum walker breaks into 2S quantum walkers.

► A giant Skyrmion collapses to a singular point by applying strong magnetic field. ► Quantum walk is realized in thin ferromagnetic films by Skyrmion collapsing. ► Quantum walks for S=1/2S=1/2 and 1 are exact solvable, where S   represents the spin. ► Quantum walks for >1/2>1/2 presents a new type of quantum walks, i.e., “multiple quantum walks”. ► Skyrmion bursts which occur simultaneously exhibit an interference as a manifestation of quantum walk.