On the statistical-mechanical meaning of the Bousso bound
On the statistical-mechanical meaning of the Bousso bound
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DOI：
10.1088/0264-9381/25/12/125005
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发表时间：
2008-03
影响因子：
3.5
通讯作者：
A. Pesci
中科院分区：
文献类型：
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作者：
A. Pesci
的Bousso熵界，在其广义的形式，调查的情况下，完美的流体在当地的热力学平衡和证据被发现，当且仅当一个特定的本地热力学性质成立，新兴的约束满足时，试图应用到薄层的物质。这个属性包括存在一个最终的下限l* 的厚度的切片，一个物理力学的描述是可行的，取决于l* 的物理变量，定义系统的状态的本地。这种极限尺度通常比普朗克尺度大得多（因此不一定需要引用普朗克尺度物理来证明它），似乎与引力无关，这表明广义熵界可能植根于传统的平坦时空统计力学，但最大公认的熵实际上也由引力决定。理想流体的一些例子被认为是为了确定的机制，可以设置一个下限的压缩力学的描述和这些系统被发现尊重下限尺度l*。光子气体，特别是，似乎饱和这一限制规模和结果得出，对于系统组成的一个单一的切片的光子气体厚度l*，广义Bousso约束饱和。有人认为，这似乎为黑洞熵的特殊理解开辟了道路：如果一个熵可以有意义地（即用第二定律）分配给一个黑洞，那么它的值A/4（其中A是黑洞的面积）只需要（传统的）统计力学耦合到广义相对论。
The Bousso entropy bound, in its generalized form, is investigated for the case of perfect fluids at local thermodynamic equilibrium and evidence is found that the bound is satisfied if and only if a certain local thermodynamic property holds, emerging when the attempt is made to apply the bound to thin layers of matter. This property consists of the existence of an ultimate lower limit l* to the thickness of the slices for which a statistical-mechanical description is viable, depending l* on the thermodynamical variables which define the state of the system locally. This limiting scale, found to be in general much larger than the Planck scale (so that no Planck scale physics must be necessarily invoked to justify it), appears not related to gravity and this suggests that the generalized entropy bound is likely to be rooted on conventional flat-spacetime statistical mechanics, with the maximum admitted entropy being however actually determined also by gravity. Some examples of ideal fluids are considered in order to identify the mechanisms which can set a lower limit to the statistical-mechanical description and these systems are found to respect the lower limiting scale l*. The photon gas, in particular, appears to seemingly saturate this limiting scale and the consequence is drawn that for systems consisting of a single slice of a photon gas with thickness l*, the generalized Bousso bound is saturated. It is argued that this seems to open the way to a peculiar understanding of black hole entropy: if an entropy can meaningfully (i.e. with a second law) be assigned to a black hole, the value A/4 for it (where A is the area of the black hole) is required simply by (conventional) statistical mechanics coupled to general relativity.