Entropy production and thermodynamic arrow of time in a recollapsing Universe

We investigate the thermodynamic arrow of time in a time-symmetrically reco llapsing Universe by calculating quantum mechanically the entropy productio n of a massive scalar field. It is found that even though the Hamiltonian h as a time-reversal symmetry with respect to the maximum expansion of the Un iverse, the entropy production is generic and the total entropy of the scal ar field increases monotonically. We conclude that the thermodynamic arrow of time is a universal phenomenon even in the expanding and subsequently re collapsing Universe due to the parametric interaction of matter field with gravity.