[en] The ultra-relativistic heavy ion experiments are aimed at observing a new state of hadron matter called quark-gluon plasma (QGP). Various different steps are involved between the nuclear collision process, QGP production and experimentally observed final results. These steps span over the whole range of QGP life history starting from its birth. In this talk, a mechanism of conversion of projectile energy into the production of this new state of matter is discussed. Schwinger's mechanism of pair production through breakdown of constant electric field is summarized. A new theoretical framework is developed to include confinement and finite spatial dimension effects on pair creation through this mechanism. Its relevance to QGP formation in ultra-relativistic heavy ion collision is pointed out. The qualitative predictions of the theory are compared and contrasted with the others published in the literature. (author). 7 refs