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Unified Models of Dark Energy and Dark Matter using Two Measures. Eduardo Guendelman, Unified Models of Dark Energy and Dark Matter using Two Measures. Eduardo Guendelman, Ben Gurion University, Israel. What is beyond the SM, 16 Conference Bled, 2013.

We introduce 4 scalar fields in 4 -D Which will play an important geometrical We introduce 4 scalar fields in 4 -D Which will play an important geometrical role, by the way, other authors have found that 4 scalar fields in 4 -D can be used to define a generally covariant mass term for the graviton. A much simpler use of four scalars in 4 D is to define a new MEASURE.

The Basic Idea of the Two Measures Theory (TMT) The Basic Idea of the Two Measures Theory (TMT)

simple example: Softly Broken Conformal Invariance, simple example: Softly Broken Conformal Invariance,

Now we will solve for the scalar Now we will solve for the scalar

Effective Potential for Exponential forms of U and V (scale invariance) Effective Potential for Exponential forms of U and V (scale invariance)

Use of these ideas for unification of dark enegy and dark matter Use of these ideas for unification of dark enegy and dark matter

In a generally covariant form We can write the energy momentum in a “fluid In a generally covariant form We can write the energy momentum in a “fluid form”

Indeed defining the four velocity Indeed defining the four velocity

The cosmic coincidence problem Which is why the dark energy and the dark matter The cosmic coincidence problem Which is why the dark energy and the dark matter are of comparable magnitudes today? , do they balance? , but M, representing the DE is a constant!

Some References • • • Dynamical measure and field theory: Guendelman, A. B. Kaganovich Some References • • • Dynamical measure and field theory: Guendelman, A. B. Kaganovich Phys. Rev. D 60: 065004, 1999. e-Print: gr-qc/9905029 . Model Constrained by S. I. : Scale invariance, new inflation and decaying lambda terms. E. I. Guendelman, Mod. Phys. Lett. A 14: 1043 -1052, 1999. e-Print: grqc/9901017 Adding curvature Square and obtaining two flat regions : Inflation and transition to a slowly accelerating phase from SSB of scale invariance. E. I. Guendelman, O. Katz, Class. Quant. Grav. 20: 1715 -1728, 2003. e-Print: grqc/0211095 Using this model plus CC in Einstein frame to get ………Emerging Universe from Scale Invariance. S. del Campo, E. I. Guendelman , R. Herrera , P. Labrana, JCAP 1006: 026, 2010. e. Print: ar. Xiv: 1006. 5734 [astro-ph. CO] Expresing the results of the above in terms of the energy density of the flat region with lower energy density : Non Singular Origin of the Universe and its Present Vacuum Energy Density. E. I. Guendelman, Int. J. Mod. Phys. A 26: 29512972, 2011. e-Print: ar. Xiv: 1103. 1427 [gr-qc] See also Proceedings of What is beyond the Standard model for the year 2011.

Dark Matter Dark Energy Unification A two measure model of dark energy and Dark Matter Dark Energy Unification A two measure model of dark energy and dark matter. E. Guendelman, D. Singleton, N. Yongram: ar. Xiv: 1205. 1056 [gr-qc], Published in JCAP 1211 (2012) 044; Unified DE/DM model with inverse Quintessence, S. Ansoldi and E. Guendelman, JCAP 1305 (2013) 036 e-Print: ar. Xiv: 1209. 4758 [gr-qc]