Abstract
It is known that Dvali-Gabadadze-Porrati (DGP) braneworld model has a self-acceleration branch. However, this cosmological solution contains a spin-2 ghost. We study the possibility of avoiding the appearance of the ghost by slightly modifying the model, introducing the second brane. As a result we find we cannot avoid the appearance of ghost by two-branes model. Then we discuss whether spin-2 ghost is really harmful or not by evaluating the rate of spontaneous particle production due to ghost instability. We explain that non-covariant cutoff momentum arises rather naturally in the case of spin-2 ghost. As a result, the particle production rate is extremely suppressed and therefore the presence of a ghost might be harmless.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
