A Scale at 10 MeV, Gravitational Topological Vacuum, and Large Extra Dimensions

作者：Aydemir, Ufuk^*

来源：Universe, 2018, 4(7): 80.

DOI：10.3390/universe4070080

• MacDowell-Mansouri formalism
• Bjorken-Zeldovich scale
• Gauss-Bonnet term
• Einstein-Cartan formalism
• Big Bang nucleosynthesis
• cosmological constant
• Kodama wavefunctions

We discuss a possible scale of gravitational origin at around 10 MeV, or 10 12 cm, which arises in theMacDowell-Mansouri formalism of gravity due to the topological Gauss-Bonnet term in the action, as pointed out by Bjorken several years ago. A length scale of the same size emerges also in the Kodama solution in gravity, which is known to be closely related to theMacDowell-Mansouri formulation. We particularly draw attention to the intriguing incident that the existence of six compact extra dimensions originated from TeV-scale quantum gravity as well points to a length scale of 10 12 cm, as the compactification scale. The presence of six such extra dimensions is also in remarkable consistency with theMacDowell-Mansouri formalism; it provides a possible explanation for the factor of similar to 10120 multiplying the Gauss-Bonnet term in the action. We also comment on the relevant implications of such a scale regarding the thermal history of the universe motivated by the fact that it is considerably close to 1-2MeV below which the weak interactions freeze out, leading to Big Bang Nucleosynthesis.

• 出版日期2018-7
• 单位华中科技大学