Effective Constraints and Physical Coherent States in Quantum Cosmology: A Numerical Comparison

Understand

A cosmological model with a cyclic interpretation is introduced, which is subject to quantum back-reaction and yet can be treated rather completely by physical coherent state as well as effective constraint techniques.

• By this comparison, the role of quantum back-reaction in quantum cosmology is unambiguously demonstrated.
• Also the complementary nature of strengths and weaknesses of the two procedures is illustrated.
• Finally, effective constraint techniques are applied to a more realistic model filled with radiation, where physical coherent states are not available.