A frame-dependent gravitational effective action mimics a cosmological   constant, but modifies the black hole horizon
  A frame dependent effective action motivated by the postulates of three-space general coordinate invariance and Weyl scaling invariance exactly mimics a cosmological constant in Robertson-Walker spacetimes. However, in a static spherically symmetric Schwarzschild-like geometry it modifies the black hole horizon structure within microscopic distances of the nominal horizon, in such a way that $g_{00}$ never vanishes. This could have important implications for the black hole "information paradox". 
Stephen L. Adler
gr-qc hep-th math-ph math.MP