Thermodynamics of fractal universe
Thermodynamics of fractal universe
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DOI：
10.1016/j.physletb.2012.12.072
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发表时间：
2012-10
影响因子：
4.4
通讯作者：
A. Sheykhi;Z. Teimoori;Bin Wang
中科院分区：
文献类型：
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作者：
A. Sheykhi;Z. Teimoori;Bin Wang
我们研究了分形宇宙中视界的热力学性质。我们发现，人们总是可以用熵平衡关系δq=ThdSh的形式改写分形宇宙的弗里德曼方程，其中δq和Thr是在视在视界内的加速观测者所看到的能量通量和Unruh温度。我们发现，熵Share由两个项组成，第一项服从通常的面积定律，第二部分是由于分形宇宙的非平衡热力学而产生的熵产生项。这表明，在一个分形宇宙中，可能需要用时空的非平衡热力学来处理。我们还在分形宇宙的框架下研究了广义热力学第二定律。当视界温度和视界内物质场的温度相等时，即T=Th，只要减速和状态方程参数取值范围为−1⩽Q<；0，−1⩽w<；−1/3或Q<；−1，w<；−1，则热力学第二定律即可满足.我们还发现，对于Th=Bt，对于b<；1，通过适当地选择分维参数β，可以保证热力学的GSL在一个分维宇宙中。
We investigate the thermodynamical properties of the apparent horizon in a fractal universe. We find that one can always rewrite the Friedmann equation of the fractal universe in the form of the entropy balance relation δQ=ThdSh, where δQ and Thare the energy flux and Unruh temperature seen by an accelerated observer just inside the apparent horizon. We find that the entropy Shconsists two terms, the first one which obeys the usual area law and the second part which is the entropy production term due to nonequilibrium thermodynamics of fractal universe. This shows that in a fractal universe, a treatment with nonequilibrium thermodynamics of spacetime may be needed. We also study the generalized second law of thermodynamics in the framework of fractal universe. When the temperature of the apparent horizon and the matter fields inside the horizon are equal, i.e. T=Th, the generalized second law of thermodynamics can be fulfilled provided the deceleration and the equation of state parameters ranges either as −1⩽q<0, −1⩽w<−1/3 or as q<−1, w<−1 which are consistent with recent observations. We also find that for Th=bT, with b<1, the GSL of thermodynamics can be secured in a fractal universe by suitably choosing the fractal parameter β.