Cosmological quantum tunneling and holographic principle

The probable trajectory of the ground state wave function of the universe arises through a quantum tunneling by gravitational instantons. We calculate the quantum tunneling rate for a $n>2$ dimensional closed Friedmann-Robertson-Walker universe with a positive cosmological constant. In four dimensions, by using of the holographic principle, the tunneling rate is related to the maximal entropy of the early universe after quantum tunneling.