Comment on time-variation of fundamental constants

M. J. Duff

paper

Comment on time-variation of fundamental constants

arXiv:hep-th/0208093

Abstract

The possible time variation of dimensionless fundamental constants of nature, such as the fine-structure constant $α$ , is a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants, such as $ℏ$ , $c$ , $G$ , $e$ , $k$ ,... which are merely human constructs whose number and values differ from one choice of units to the next, has no operational meaning. To illustrate this, we refute a recent claim of Davies et al that black holes can discriminate between two contending theories of varying $α$ , one with varying $c$ and the other with varying $e$ . In Appendix A we respond to criticisms by P. Davies and two Nature referees. In Appendix B we respond to remarks by Magueijo and by T. Davis. In Appendix C we critique recent claims by Copi, A. Davis and Krauss to have placed constraints on $Δ G / G$ .} In Appendix D we provide extracts of a lecture by Dirac, of which we have only recently become aware, which includes the comment "Talking about whether a thing is constant or not does not have any absolute meaning unless that quantity is dimensionless".

In an Appendix we provide extracts of a lecture by Dirac, of which we have only recently become aware, which includes the comment "Talking about whether a thing is constant or not does not have any absolute meaning unless that quantity is dimensionless"

Comment on time-variation of fundamental constants

Abstract

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