Cosmology from quantum potential in brane–anti-brane system

Recently, some authors removed the big-bang singularity and predicted an infinite age of our universe. In this paper, we show that the same result can be obtained in string theory and M-theory; however, the shape of universe changes in different epochs. In our mechanism, first, N fundamental string decay to N D0–anti-D0-brane. Then, D0-branes join each other, grow and form a six-dimensional brane–antibrane system. This system is unstable, broken and at present the form of four-dimensional universes, one anti-universe in addition to one wormhole are produced. Thus, there isn't any big-bang in cosmology and the universe is a fundamental string at the beginning. Also, the total age of universe contains two parts, one is related to initial age and the other corresponds to the present age of universe ( ttot=tinitial+tpresent ). On the other hand, the initial age of universe includes two parts, the age of fundamental string and the time of transition ( tinitial=ttransition+tf-string ). We observe that only in the case of ( tf-string→∞ ), the scale factor of universe is zero and as a result, the total age of universe is infinity