Tian, Y (reprint author), Univ Chinese Acad Sci, Sch Phys, Beijing 100049, Peoples R China.
[Tian, Yu] Univ Chinese Acad Sci, Sch Phys, Beijing 100049, Peoples R China
; [Tian, Yu
; Wu, Xiao-Ning] Chinese Acad Sci, Inst Theoret Phys, State Key Lab Theoret Phys, Beijing 100190, Peoples R China
; [Wu, Xiao-Ning] Chinese Acad Sci, Acad Math & Syst Sci, Inst Math, Beijing 100190, Peoples R China
; [Zhang, Hongbao] Vrije Univ Brussel, B-1050 Brussels, Belgium
; [Zhang, Hongbao] Int Solvay Inst, B-1050 Brussels, Belgium
The suspicion that gravity is holographic has been supported mainly by a variety of specific examples from string theory. In this paper, we propose that such a holography can actually be observed in the context of Einstein's gravity and at least a class of generalized gravitational theories, based on a definite holographic principle where neither is the bulk space-time required to be asymptotically AdS nor the boundary to be located at conformal infinity, echoing Wilson's formulation of quantum field theory. After showing the general equilibrium thermodynamics from the corresponding holographic dictionary, in particular, we provide a rather general proof of the equality between the entropy production on the boundary and the increase of black hole entropy in the bulk, which can be regarded as strong support to this holographic principle. The entropy production in the familiar holographic superconductors/superfluids is investigated as an important example, where the role played by the holographic renormalization is explained.