عنوان مجله
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COMMUNICATIONS IN THEORETICAL PHYSICS
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چکیده
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We study thermodynamics of the parabolic Lemaitre–Tolman–Bondi (LTB) cosmology supported by a
perfect fluid source. This model is the natural generalization of the flat Friedmann–Robertson–Walker (FRW) universe,
and describes an inhomogeneous universe with spherical symmetry. After reviewing some basic equations in the parabolic
LTB cosmology, we obtain a relation for the deceleration parameter in this model. We also obtain a condition for which
the universe undergoes an accelerating phase at the present time. We use the first law of thermodynamics on the
apparent horizon together with the Einstein field equations to get a relation for the apparent horizon entropy in LTB
cosmology. We find out that in LTB model of cosmology, the apparent horizon’s entropy could be feeded by a term,
which incorporates the effects of the inhomogeneity. We consider this result and get a relation for the total entropy
evolution, which is used to examine the generalized second law of thermodynamics for an accelerating universe. We also
verify the validity of the second law and the generalized second law of thermodynamics for a universe filled with some
kinds of matters bounded by the event horizon in the framework of the parabolic LTB model.
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