Speaker
Description
We analyze the Extended Quasi-Dilaton Massive Gravity model around a Friedmann-Lemaitre-Robertson-Walker cosmological background. We present a careful stability analysis of asymptotic fixed points. We find that the traditional fixed point cannot be approached dynamically, except from a perfectly fine-tuned initial condition involving both the quasi-dilaton and the Hubble parameter. A less-well examined fixed-point solution, where the time derivative of the 0-th Stuckelberg field vanishes $\dot\phi^0=0$, encounters no such difficulty, and the fixed point is an attractor in some finite region of initial conditions. We examine the question of the presence of a Boulware-Deser ghost in the theory. We show that the additional constraint which generically allows for the elimination of the Boulware-Deser mode is $\textit{only}$ present under special initial conditions. We find that the only possibility corresponds to the traditional fixed point, and the initial conditions are the same fine-tuned conditions that allow the fixed point to be approached dynamically.
Statement of Acknowledgement: This presentation was made possible, in part, through financial support from the School of Graduate Studies at Case Western Reserve University.
