Quantum fluctuations and degeneracies of two-dimensional magnetic skyrmions

Abstract

In this thesis we use Holstein-Primakoff and Bogoliubov transformations to find the zero-point quantum fluctuations of two-dimensional magnetic skyrmion configurations found by R. Keesman et al. (arXiv:1506.00271). We show that skyrmions are promoted by quantum fluctuations as they lower the groundstate energy and increase the domains in which skyrmions were expected classically. More specifically, we show that quantum fluctuations shift the parameter values (spin coupling, Dzyaloshinskii-Moriya interaction, external magnetic field) at which degenerate skyrmion configurations occur, as classically degenerate skyrmion configurations generally have different zero-point energies. Our calculations show that these effects are large enough to be measurable.