Explanation of the accelerated expansion of the universe and dark energy with irreversible thermodynamics∗

摘要

In this paper, by invoking the laws of irreversible thermodyudnamics the accelerated expansion of the universe isudexplained. It is shown that the entropy of the universe, at anudy particular instant of time, plays a significant roleudin the accelerated expansion of the universe. Considering tudhe universe to be filled with a classical mono-atomic,udhomogeneous and isotropic gas under classical non-equilibudrium situations, two generalized forces causing theudexpansion of the universe are arrived at. One of the two forceuds, the trivial force, has affinity to volume expansionudand the non-trivial force has affinity to spatial expansion.udThe acceleration of the expansion of the universe is dueudto the spatial expansion caused by the non-trivial force andudwhich in turn might account for the presence of the darkudenergy. It is shown in this paper that the non-trivial generaudlized force and the dark energy, providing the negativeudpressure for spatial expansion, can be explained with irrevudersible thermodynamics.