We show that the coherent oscillations of the e.m. field induced by the
collective quantum fluctuations of the nuclear matter field associated with the
giant resonances, with frequencies ωA≃78A−1/3 MeV, give
rise to a significant (e+e−) pair production in high energy Heavy Ion
collisions. The approximate parameterless calculation of such yield is in good
agreement with recent experimental observations.Comment: 27 pages, 13 figure