A linear quantum dynamical theory for squeezing the output of the trapped
Bose-Einstein condensate is presented with the Bogoliubov approximation. We
observe that the non-classical properties, such as sub-Poisson distribution and
quadrature squeezing effect, mutually oscillate between the quantum states of
the applied optical field and the resulting atom laser beam with time. In
particular, it is shown that an initially squeezed optical field will lead to
squeezing in the outcoupled atomic beam at later times.Comment: 6 pages, Latex file, Phys.Rev.A 63(2001)1560