Creating big time crystals with ultracold atoms

We investigate the size of discrete time crystals in the range s = 10 - 100 (ratio of response period to driving period) that can be created for a Bose-Einstein condensate (BEC) bouncing resonantly on an oscillating mirror. We consider the effects of having a realistic soft Gaussian potential mirror for the bouncing BEC, such as that produced by a repulsive light-sheet, which is found to have a significant effect on the dynamics of the system. Finally, we discuss the choice of atomic system for creating time crystals based on a bouncing BEC and present an experimental protocol for realizing big time crystals. Such a system provides a platform for investigating a broad range of non-trivial condensed matter phenomena in the time domain.