Nima Khosravi

Department of Physics, Sharif University of Technology,

Department of Physics, Shahid Beheshti University

Random Matrix Gravity and Double Hierarchy Problem 

 

Abstract: Why are the cosmological constant, electroweak and Planck scales so different? This “double hierarchy” problem, where Λ≪M^2_EW≪M^2_p, is one of the most pressing in fundamental physics. We show that in a theory of N randomly coupled massive gravitons at the electroweak scale, these scales are linked precisely by such a double hierarchy for large N, with intriguing cosmological consequences. Surprisingly, in all the physical scales, only one massless graviton emerges which is also, effectively, the only one that is coupled to matter, giving rise to standard Einstein gravity, with M^2_pGμν=Tμν at large N. In addition, there is a tower of massive gravitons, the lightest of which can drive late-time acceleration. In this scenario, the observed empirical relation ΛMp^2∼M_EW^4 as well as the double hierarchy, arise naturally since since Λ ∼ M_EW^2/√(N) and Mp^2 ∼ √(N)M_EW^2.

یکشنبه  8 مهر 1403، ساعت 17:00

Sunday 29 September 2024 – 17:00 Tehran Time

Hybrid Seminar

دانشکده فیزیک – طبقه اول – کلاس فیزیک 3 Physics Department – first floor – Room Physics 3   /

https://vc.sharif.edu/ch/cosmology

گزینه ورود به صورت مهمان – Enter as a Guest