Wehrl's entropy and a measure of intermode correlations in phase space

The properties of the entangled pure states in phase space are analysed usi ng the classical entropy introduced by Wehrl. The general entropy inequalit ies for non-entangled pure states are derived, which are violated by any en tangled state. To measure the strength of intermode correlations in phase s pace the parameters related to these inequalities are proposed. As an examp le we study the correlations between amplitudes and phases for two-mode Foc k states. We find that the amplitudes as well as phases of different modes are correlated. It is also shown that the degree of the intermode correlati on strongly depends on the photon number difference in two-mode Fock states .