Constraints on Space-Time-Matter Theory in the Framework of the Standard-Model Extension

James Overduin,Hamna Ali,Francis Walz

doi:10.3390/galaxies9020026

James Overduin, Hamna Ali + Show 1 more

Open Access

https://doi.org/10.3390/galaxies9020026

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Abstract

We use experimental limits on Lorentz violation within the framework of the Standard-Model Extension to derive quantitative constraints on Space-Time-Matter theory, a version of Kaluza–Klein theory in which the cylinder condition is relaxed so that four-dimensional physics can in principle depend on the extra coordinates. The extra dimensions are not necessarily compact or length-like. We find that the associated variation in fundamental quantities such as rest mass must occur slowly, on cosmological scales.

Highlights

Space-Time-Matter TheoryCurrent approaches to unification of fundamental interactions based on extra dimensions assume that those dimensions are compact and undetectable at experimentally accessible energies (as in string theories), or that they are large but “off limits” to standardmodel fields (as in brane theories), or that they are mathematical artifacts only (as in projective theories)
We use experimental limits on Lorentz violation within the framework of the StandardModel Extension to derive quantitative constraints on Space-Time-Matter theory, a version of Kaluza
It is not necessarily ad hoc to allow gravitons to propagate off the brane, while all other fields are restricted to it

Summary

Space-Time-Matter Theory

Current approaches to unification of fundamental interactions based on extra dimensions assume that those dimensions are compact and undetectable at experimentally accessible energies (as in string theories), or that they are large but “off limits” to standardmodel fields (as in brane theories), or that they are mathematical artifacts only (as in projective theories). Space-Time-Matter or STM theory ( referred to by some authors as Kaluza–Klein gravity or induced-matter theory) is an alternative approach in which cylindricity is not imposed from the outset, and extra coordinates are not assumed to be closed or compact in scale, or even to have the physical dimension of length [4,5,6]. The approach is general: to take the new coordinates seriously, whatever their physical dimension, and not to unnecessarily hobble the theory by imposing cylindricity from the outset. To put it in colloquial terms: not to throw out the baby of possible new physics with the bathwater of Lorentz violation.

Physical Interpretation

Lorentz Violation in the Flat-Space Limit

Findings

Conclusions and Discussion