Relative Phase and Coherence in Bright Matter-Wave Solitons

Bright matter-wave solitons are self-stabilizing waves composed of ultracold atoms, which are robust to collisions, that is they behave in a particle-like way. They are formed from ultracold dilute atomic gases which have undergone a phase transition to a Bose-Einstein condensate, where the atoms in a sense all behave as one. Bright matter-wave solitons are observed to emerge from such an atomic Bose-Einstein condensate when, through appropriate control of magnetic fields, the atoms change from repelling one another, to feeling an attraction to one another. This process usually results in the formation of several solitons, which are generally thought to have a well-defined phase with respect to one another. In addition to their fundamental interest, bright matter-wave solitons offer advantages in matter-wave-based ideas on precision measurement. Such technologies require a source of reproducible bright matter-wave solitons and an understanding of their properties; it is therefore of crucial importance, as well as fundamental interest, to understand the process of soliton formation and soliton dynamics, particularly with regard to their phase properties and long-term stability.