  Following the recent work of Connes, Douglas and Schwarz, we study the
M(atrix) model compactified on a torus with a background of the three-form
field. This model is given by a super Yang-Mills theory on a quantum torus. To
consider twisted gauge field configurations, we construct twisted U(n) bundles
on the quantum torus as a deformation of its classical counterpart. By properly
taking into account membranes winding around the light-cone direction, we
derive from the M(atrix) model the BPS spectrum which respects the full
SL(2,Z)*SL(2,Z) U-duality in M theory.
