Quantum dynamics and response functions of skyrmions

Recent research activities have turned to studying quantum effects in skyrmion-hosting ordered phases within the context of numerical diagonalization of quantum spin Hamiltonians as well as semiclassical magnonic theories. One of the works on two-dimensional chiral magnets has unveiled a force due to magnons exerting on a skyrmion sitting in a field-polarized ferromagnetic background. It arises from the scattering between the magnons and the skyrmion. In this talk, it will be shown how magnons in a skyrmion gas scatter off multiple skyrmions, and how this effectively generates an inter-skyrmiom interaction. Various features of this novel interaction such as its temperature dependence and its dependence on skyrmion density will be discussed. Finally, results from the same semiclassical theory on various correlation functions, which lie at the heart of linear responses of skyrmions to external probes, will be reported.