author={John W. Moffat},
  journal={International Journal of Modern Physics D},
  • J. Moffat
  • Published 5 February 2002
  • Physics
  • International Journal of Modern Physics D
In the bimetric scalar–tensor gravitational theory there are two frames associated with the two metrics ĝμν and gμν, which are linked by the gradients of a scalar field ϕ. The choice of a comoving frame for the metric ĝμν or gμν has fundamental physical consequences for local observers in either metric spacetimes, while maintaining diffeomorphism invariance. If the metric gμν is chosen to be associated with comoving coordinates, then the speed of light varies in the frame with the metric… 
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