شماره راهنما :
1160 دكتري
پديد آورنده :
عبوديت، فاطمه
عنوان :
نظريه هاي اصلاح شده گرانش
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك
صفحه شمار :
[ح]، ۱۵۶ص.: مصور، جدول
استاد راهنما :
بهروز ميرزا
توصيفگر ها :
سامانه هاي ديناميكي , نظريه ميمتيك , عدم قطعيت تعميم يافته , گذارفاز در سياه چاله ها
استاد داور :
مدعو: علي مهدي فر، مجيد منعم زاده; داور داخلي: احمد شيرزاد
تاريخ ورود اطلاعات :
1396/12/23
كد ايرانداك :
ID1160 دكتري
چكيده انگليسي :
abstractThe thesis is devoted to study modified theories of gravity After a short review on the action and equa tions of motion of General Relativity and Friedman equations f R T theory is explained where Tis the trace of energy momentum tensor and R is Richi scalar is explained After obtaining equationsof motion we study future singularities of two kinds of equations of state for this theory We willsee assuming conservation of energy and a constant equation of state parameter there is no futuresingularity but with changing equation of state it is possible to have some kinds of singularity whichare categurized for this theory Then we studied Neother symmetry for f R T theory and calcu lated the conserved charge and Neother functions for two special cases After that a short review onfundamentals of teleparallel gravity is presented which is an equivalent General Relativity with thedifference that space time is assumed to be twisted flat defined with Weitzenboch connection Thenf T theory is studied which is a straight forward modification of teleparalell gravity like f R the ory for General Relativity Then the method of dynamical systems is explained and three theories ofgravity f R T f R T R T and f T is checked with this method Critical points and phasetrajectories are studied for these theories We found f T and f R T theories are able to explainthe nowadays acceleration of the universe and some parts of standard cosmology Finally mimetictheory is explained which is a solution to the problem of dark energy and dark matter This theory isextended to explain f T mimetic dark matter
استاد راهنما :
بهروز ميرزا
استاد داور :
مدعو: علي مهدي فر، مجيد منعم زاده; داور داخلي: احمد شيرزاد
