Cosmological topologically massive gravitons and photons

Abstract

We study topologically massive (2+1)-dimensional gravity with a negative
\ncosmological constant. The masses of the linearized curvature excitations about
\nAdS3 backgrounds are not only shifted from their flat background values but
\nalso, more surprisingly, split according to chirality. For all finite values of the
\ntopological mass, we find a single bulk degree of freedom with positive energy,
\nand exhibit a complete set of normalizable, finite-energy wave packet solutions.
\nThis model can also be written as a sum of two higher-derivative SL(2,R)
\nChern–Simons theories, weighted by the central charges of the boundary
\nconformal field theory. At two particular ‘critical’ values of the couplings, one
\nof these central charges vanishes, and linearized topologically massive gravity
\nbecomes equivalent to topologically massive electromagnetism; however, the
\nphysics of the bulk wave packets remains unaltered here.