Multigravity and the cosmological constant

Abstract

The possibility of flat metric solutions in the presence of arbitrary, in particular, Planck mass sized cosmological constants is investigated within multigravity theory, the ghost-free theory of $(N+1)$ rank-2 tensor fields comprising one massless and $N$ massive spin-2 fields. It is found that, indeed, for any $N$, no matter how large, no flat solutions exist without fine-tuning parameters in the potential. For an infinite number of fields, however, flat solutions exist within an infinite-dimensional parameter space. Such a ground state may be viewed as a collective state that cannot be approximated by any finite $N$.

Comments: 8 pages