http://arxiv.org/abs/1706.00791
In a recent paper [D. Philipp, V. Perlick, D. Puetzfeld, E. Hackmann, and C. L\”ammerzahl, Phys. Rev. D 95, 104037 (2017)], a definition of a general-relativistic geoid, restricted to stationary spacetimes, was presented in terms of “isochronometric surfaces”. In this note, we explicate how this definition is just a special, highly restrictive case of our earlier formulation of the general-relativistic geoid using quasilocal frames, which is valid for generic, non-stationary spacetimes [M. Oltean, R.J. Epp, P.L. McGrath, and R.B. Mann, Class. Quantum Grav. 33, 105001 (2016)]. Moreover, like the isochronometric surface geoid, we show how our “geoid quasilocal frame” (GQF) can also be defined, simply and operationally, in terms of redshift measurements.
M. Oltean, R. Epp, P. McGrath, et. al.
Mon, 19 Jun 17
41/48
Comments: 6 pages, 1 figure