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Sharif University of Technology - Weekly Cosmology Seminar ( Sunday- 9 April 2017 - 20 Farvardin 1396)

دانشکده فیزیک دانشگاه صنعتی شریف

 

سمینار هفتگی گروه کیهان شناسی

 

 Energy-Momentum squared gravity (EMSG)

محمود روشن  (گروه فیزیک دانشکده علوم دانشگاه فردوسی مشهد)

 

Abstract:   

In this talk I review a covariant generalization of Einstein's general relativity which allows the existence of a term proportional to T_{\alpha\beta} T^{\alpha\beta} in the action functional of the theory ( T_{\alpha\beta} is the energy-momentum tensor). This simple generalization leads to interesting consequences in the early universe. Applying this theory to a homogeneous and isotropic spacetime, we find that there is a maximum energy density ρ_{max}, and correspondingly a minimum length a_{min}, in the thermal history of the universe. This means that there is a bounce at early times, and this theory avoids the existence of an early-time singularity. Also I review the possible consequences of this theory in the dynamics of compact objects like Neutron stars. More specifically I discuss the mass-radius relation for Neutron stars in this model.

The talk is based on the following paper:Roshan and Shojai PRD 2016: 10.1103/PhysRevD.94.044002

 

 

یکشنبه 20 فروردین ماه 1396، ساعت 15:00

    دانشکده فیزیک، طبقه اول کلاس فیزیک 3

physics.sharif.edu/~cosmology/