KIP-Veröffentlichungen

In this thesis, we investigate the far-from-equilibrium dynamics of one-dimensional and quasi-one-dimensional spin-1 Bose-Einstein condensates based on numerical simulations, caused by different types of excitations. We assume the double sine-Gordon (DSG) model as an effective low-energy field theory for the spinor phase, which
leads to a periodic potential and allows (quasi-)topological excitations such as sine-Gordon-type solitons. We provide numerical simulations based on the split-step Fourier method to solve the classical equations of motion, while incorporating quantum fluctuations via the truncated Wigner approximation and study the system’s evolution after applying sine-Gordon soliton excitations in purely 1D and quasi-1D geometries, as well as spin wave excitations in quasi-1D. We analyze the simulations regarding the space-time evolution, the dynamics of the system’s order parameter and the distribution of the spinor phase across the minima of the DSG potential.
We observe critically slowed dynamics in the evolution of correlation function of the order parameter, characterized by a universal scaling behavior with exponents α ≈ β ≈ 1/4 for solitons in 1D, and β ≈ 1/3 for spin waves and solitons in quasi-1D. A comparison with previous studies supports the hypothesis that the distribution across multiple minima of the periodic DSG potential influences the universal scaling class of the system’s dynamics.