We propose a method to produce a definite number of ground-state atoms by adiabatic reduction of the depth of a potential well that confines a degenerate Bose gas with repulsive interactions. Using a variety of methods, we map out the maximum number of particles that can be supported by the well as a function of the well depth and interaction strength, covering the limiting case of a Tonks gas as well as the mean-field regime. We also estimate the time scales for adiabaticity and discuss the recent observation of atomic number squeezing [Chuu et al., Phys. Rev. Lett. 95, 260403 (2005)].

• Received 11 July 2006

DOI:https://doi.org/10.1103/PhysRevLett.98.063001