2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/36189If one introduces causality into quantum cosmology, then the prescription for the no-boundary universe should be revised. We show that the thermodymanic arrow of time associated with the perturbation modes should be reversed at the maximum expansion for the oscillating Hawking model. To an observer equipped with the time arrow, the universe will terminate its evolution after an half cycle.10 pagesGeneral Relativity and Quantum CosmologyCausality, Time Arrow and Half Cycling Universetext