1204.5604 (Jaume de Haro)
Jaume de Haro
Different approaches to quantum cosmology are studied in order to deal with the future singularity avoidance problem. Our results show that these future singularities will persist but could take different forms. As an example we have studied the big rip which appear when one considers the state equation $P=\omega\rho$ with $\omega<-1$, showing that it does not disappear in modified gravity nor in the Randall-Sundrum escenario. On the other hand, it is well-known that quantum geometric effects in loop quantum cosmology introduce modifications in Friedmann's equation that replace the big rip by a non-singular bounce. However this modified Friedmann equation is obtained in an inconsistent way, what means that the obtained results from this equation, in particular singularity avoidance, are incorrect. In fact, we will show that instead of a non-singular bounce, the big rip singularity is replaced, in loop quantum cosmology, by a Type IV singularity.
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http://arxiv.org/abs/1204.5604
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