2010/09/30 by J. J. Lopez-Villarejo · 2 citations
Physics and Astronomy · Mathematics · #hep-th #gr-qc #math-ph #math.MP
paper · pdf · doi:10.1088/1475-7516/2011/11/002
published as JCAP11(2011)002 · 10 pages; amsart style; v3: version as appeared in JCAP, redaction improved
arxiv created 2012/05/22 · arxiv updated 2012/05/23
Transverse Diffeomorphism (TDiff) theories are well-motivated theories of gravity from the quantum perspective, which are based upon a gauge symmetry principle. The main contribution of this work is to firmly establish a correspondence between TransverseDiff and the better-known scalar-tensor gravity --- in its more general form ---, a relation which is completely analogous to that between unimodular gravity and General Relativity. We then comment on observational aspects of TDiff. In connection with this proof, we derive a very general rule that determines under what conditions the procedure of fixing a gauge symmetry can be equivalently applied before the variational principle leading to the equations of motion, as opposed to the standard procedure, which takes place afterwards; this rule applies to gauge-fixing terms without derivatives.