Dynamics of a Bose-Einstein condensate

This thesis presents a series of experiments aiming at characterizing the dynamics of a dilute Bose-Einstein condensate, focusing on its behaviour when stirred-up. Using a far-detuned laser beam, we have realized a dipole potential mimicking the rotating bucket experiment previously performed on Helium II: the stirring-up of the condensate generates quantized vortices characterized by a phase defect at their core. This topological defect has been directly detected by an atom interferometry experiment performed on two wave packets spatially separated. Moreover the angular momentum has been measured by surface mode spectroscopy of the cloud, allowing us to precise the actual nucleation mechanism of the vortices. These are generated through a dynamical instability of the condensate that crucially depends on the geometry of the stirrer. (author)