Quantum dynamics of skyrmions in chiral magnets

Magnetic skyrmions are topologically protected spin structures that have emerged as attractive candidates for magnetic storage applications in a rapidly developing field known as skyrmionics. Skyrmions are typically described as classical magnetic textures which propagate with high mobility due to the absence of a mass, while damping is usually included phenomenologically.
The goal of this work is to go beyond this classical limit by providing a full quantum description of the propagation of skyrmions in insulating magnetic films at zero and finite temperatures. The quantum features become increasingly relevant for skyrmions at the nanometer scale where quantum fluctuations play an important role. The backaction of these magnon like modes on the skyrmion strongly affects its dynamics by giving rise to microscopic damping terms in the equation of motion that are non-local in time. As a striking consequence we find that the skyrmion can acquire an inertial mass not only at finite but also at zero-temperatures due to non-uniform magnetic terms that break translational invariance such as defects or magnetic traps. Our work shows that skyrmions are most promising candidates for the study of macroscopic quantum effects involving the collective motion of tens of thousands of spins.