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. 
F. Darabi and S. Jalalzadeh
gr-qc