Generalized Second Law of Thermodynamics in Parabolic LTB Inhomogeneous Cosmology

(整期优先)网络出版时间:2015-11-21
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WestudythermodynamicsoftheparabolicLemaitre-Tolman-Bondi(LTB)cosmologysupportedbyaperfectSuidsource.ThismodelisthenaturalgeneralizationoftheSatFriedmann-Robertson-Walker(FRW)universe,anddescribesaninhomogeneousuniversewithsphericalsymmetry.AfterreviewingsomebasicequationsintheparabolicLTBcosmology,weobtainarelationforthedecelerationparameterinthismodel.Wealsoobtainaconditionforwhichtheuniverseundergoesanacceleratingphaseatthepresenttime.WeusethefirstlawofthermodynamicsontheapparenthorizontogetherwiththeEinsteinfieldequationstogetarelationfortheapparenthorizonentropyinLTBcosmology.WefindoutthatinLTBmodelofcosmology,theapparenthorizon’sentropycouldbefeededbyaterm,whichincorporatestheeffectsoftheinhomogeneity.Weconsiderthisresultandgetarelationforthetotalentropyevolution,whichisusedtoexaminethegeneralizedsecondlawofthermodynamicsforanacceleratinguniverse.WealsoverifythevalidityofthesecondlawandthegeneralizedsecondlawofthermodynamicsforauniversefilledwithsomekindsofmattersboundedbytheeventhorizonintheframeworkoftheparabolicLTBmodel.