On the cosmology of scalar-tensor-vector gravity theory
We consider the cosmological consequences of a special scalar-tensor-vector theory of gravity, known as MOG (for MOdified Gravity), proposed to address the dark matter problem. This theory introduces two scalar fields G ( x ) and μ( x ), and one vector field ##IMG## [http://ej.iop.org/icons/Entities...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
29 January 2018
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| In: |
Journal of cosmology and astroparticle physics
Year: 2018, Issue: 1, Pages: ? |
| ISSN: | 1475-7516 |
| DOI: | 10.1088/1475-7516/2018/01/048 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1088/1475-7516/2018/01/048 Verlag, Volltext: http://stacks.iop.org/1475-7516/2018/i=01/a=048 
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| Author Notes: | Sara Jamali, Mahmood Roshan and Luca Amendola |
| Summary: | We consider the cosmological consequences of a special scalar-tensor-vector theory of gravity, known as MOG (for MOdified Gravity), proposed to address the dark matter problem. This theory introduces two scalar fields G ( x ) and μ( x ), and one vector field ##IMG## [http://ej.iop.org/icons/Entities/phi.gif] phi α ( x ), in addition to the metric tensor. We set the corresponding self-interaction potentials to zero, as in the standard form of MOG. Then using the phase space analysis in the flat Friedmann-Robertson-Walker background, we show that the theory possesses a viable sequence of cosmological epochs with acceptable time dependency for the cosmic scale factor. We also investigate MOG's potential as a dark energy model and show that extra fields in MOG cannot provide a late time accelerated expansion. Furthermore, using a dynamical system approach to solve the non-linear field equations numerically, we calculate the angular size of the sound horizon, i.e. θ s , in MOG. We find that 8× 10 −3 rad<θ s <8.2× 10 −3 rad which is way outside the current observational bounds. Finally, we generalize MOG to a modified form called mMOG, and we find that mMOG passes the sound-horizon constraint. However, mMOG also cannot be considered as a dark energy model unless one adds a cosmological constant, and more importantly, the matter dominated era is still slightly different from the standard case. |
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| Item Description: | Gesehen am 09.03.2018 |
| Physical Description: | Online Resource |
| ISSN: | 1475-7516 |
| DOI: | 10.1088/1475-7516/2018/01/048 |