Bounds on cosmological variation of fundamental constants of non-gravitational physics. For an in-depth review, see .
The PPN Parameters and their significance (note that has been shown twice to indicate that it is a measure of two effects).
Metric theories and their PPN parameter values ( for all cases). The parameters , , , and denote complicated functions of and of the arbitrary constants. Here is not the cosmological constant , but is defined by Equation (37).
Current limits on the PPN parameters. Here is a combination of other parameters given by .
Constancy of the gravitational constant. For binary pulsar data, the bounds are dependent upon the theory of gravity in the strong-field regime and on neutron star equation of state. Big-bang nucleosynthesis bounds assume specific form for time dependence of G.
Parameters of the binary pulsar B1913+16. The numbers in parentheses denote errors in the last digit. Data taken from [18, 272]. Note that is not the same as the PPN parameter (see Equations (78)).
Parameters of other binary pulsars. References may be found in the text; for an online catalogue of pulsars with reasonably up-to-date parameters, see .
© Max Planck Society and the author(s)