Cosmology from quantum potential in brane–anti-brane system

Abstract

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.