title: Effective scenario of loop quantum cosmology.
abstract: Semiclassical states in isotropic loop quantum cosmology are employed to show that the improved dynamics has the correct classical limit. The effective Hamiltonian for the quantum cosmological model with a massless scalar field is thus obtained, which incorporates also the next to leading order quantum corrections. The possibility that the higher order correction terms may lead to significant departure from the leading order effective scenario is revealed. If the semiclassicality of the model is maintained in the large scale limit, there are great possibilities for a k=0 Friedmann expanding universe to undergo a collapse in the future due to the quantum gravity effect. Thus the quantum bounce and collapse may contribute a cyclic universe in the new scenario.
authors.affiliation: Department of Physics, Beijing Normal University, Beijing 100875, China. youding@gmail.com
authors.forename: You
authors.initials: Y
authors.lastname: Ding
authors.forename: Yongge
authors.initials: Y
authors.lastname: Ma
authors.forename: Jinsong
authors.initials: J
authors.lastname: Yang