Structure Formation in a Quenched Antiferromagnetic Spinor Bose-Einstein Condensate


In this thesis, we study the structure formation following a quench of the detuning of spin exchange. For this, we employ an effective spin-1 87Rb Bose-Einstein condensate in a one-dimensional situation. Bogoliubov theory predicts unstable momentum modes for specific regimes of the detuning. These are populated by spin-changing collisions and the emerging structure can be observed in the transversal spin directions. We present our experimental system and discuss the relevant parameters. After introducing two analysis methods, the spin Fourier spectrum and the spatial correlation function, we compare the homogeneous Bogoliubov theory to the experimentally obtained results for short evolution times. The characteristic structure size follows the theoretical predictions. Further, we discuss longer evolution times where the Bogoliubov approximation becomes invalid. The observed behaviour can be partially understood by an altered interaction strength due to the depletion of the condensed mode. We see first indications for emerging structures that cannot be explained by Bogoliubov theory.