Physical basis for the symmetries in the Friedmann–Robertson–Walker metric

http://hdl.handle.net/10150/614770
Title:
Physical basis for the symmetries in the Friedmann–Robertson–Walker metric
Author:
Melia, Fulvio
Affiliation:
The University of Arizona
Issue Date:
2016-03-03
Publisher:
Springer Verlag
Citation:
Physical basis for the symmetries in the Friedmann–Robertson–Walker metric 2016, 11 (4) Frontiers of Physics
Journal:
Frontiers of Physics
Rights:
© Higher Education Press and Springer-Verlag Berlin Heidelberg 2016
Collection Information:
Abstract:
Modern cosmological theory is based on the Friedmann-Robertson-Walker (FRW) metric. Often written in terms of co-moving coordinates, this well-known solution to Einstein's equations owes its elegant and highly practical formulation to the Cosmological principal and Weyl's postulate, upon which it is founded. But there is physics behind such symmetries, and not all of it has yet been recognized. In this paper, we derive the FRW metric coefficients from the general form of the spherically-symmetric line element, and demonstrate that, because the co-moving frame also happens to be in free fall, the symmetries in FRW are valid only for a medium with zero active mass. In other words, the spacetime of a perfect fluid in cosmology may be correctly written as FRW only when its equation-of-state is $\rho+3p=0$, in terms of the {\it total} pressure $p$ and {\it total} energy density $\rho$. There is now compelling observational support for this conclusion, including the Alcock-Paczy\'nski test, which shows that only an FRW cosmology with zero active mass is consistent with the latest model-independent Baryon Acoustic Oscillation data.
ISSN:
2095-0462; 2095-0470
DOI:
10.1007/s11467-016-0557-6
Keywords:
cosmological parameters; cosmological observations; cosmological theory; gravitation
Version:
Final accepted manuscript

DC FieldValue Language
dc.contributor.authorMelia, Fulvioen
dc.date.accessioned2016-06-25T01:05:25Z-
dc.date.available2016-06-25T01:05:25Z-
dc.date.issued2016-03-03-
dc.identifier.citationPhysical basis for the symmetries in the Friedmann–Robertson–Walker metric 2016, 11 (4) Frontiers of Physicsen
dc.identifier.issn2095-0462-
dc.identifier.issn2095-0470-
dc.identifier.doi10.1007/s11467-016-0557-6-
dc.identifier.urihttp://hdl.handle.net/10150/614770-
dc.description.abstractModern cosmological theory is based on the Friedmann-Robertson-Walker (FRW) metric. Often written in terms of co-moving coordinates, this well-known solution to Einstein's equations owes its elegant and highly practical formulation to the Cosmological principal and Weyl's postulate, upon which it is founded. But there is physics behind such symmetries, and not all of it has yet been recognized. In this paper, we derive the FRW metric coefficients from the general form of the spherically-symmetric line element, and demonstrate that, because the co-moving frame also happens to be in free fall, the symmetries in FRW are valid only for a medium with zero active mass. In other words, the spacetime of a perfect fluid in cosmology may be correctly written as FRW only when its equation-of-state is $\rho+3p=0$, in terms of the {\it total} pressure $p$ and {\it total} energy density $\rho$. There is now compelling observational support for this conclusion, including the Alcock-Paczy\'nski test, which shows that only an FRW cosmology with zero active mass is consistent with the latest model-independent Baryon Acoustic Oscillation data.en
dc.language.isoenen
dc.publisherSpringer Verlagen
dc.rights© Higher Education Press and Springer-Verlag Berlin Heidelberg 2016en
dc.subjectcosmological parametersen
dc.subjectcosmological observationsen
dc.subjectcosmological theoryen
dc.subjectgravitationen
dc.titlePhysical basis for the symmetries in the Friedmann–Robertson–Walker metricen
dc.typeArticleen
dc.contributor.departmentThe University of Arizonaen
dc.identifier.journalFrontiers of Physicsen
dc.eprint.versionFinal accepted manuscripten