In this paper we study the geometry and the thermodynamics of a holographic
screen in the framework of the ultraviolet self-complete quantum gravity. To
achieve this goal we construct a new static, neutral, non-rotating black hole
metric, whose outer (event) horizon coincides with the surface of the screen.
The space-time admits an extremal configuration corresponding to the minimal
holographic screen and having both mass and radius equalling the Planck units.
We identify this object as the space-time fundamental building block, whose
interior is physically unaccessible and cannot be probed even during the
Hawking evaporation terminal phase. In agreement with the holographic
principle, relevant processes take place on the screen surface. The area
quantization leads to a discrete mass spectrum. An analysis of the entropy
shows that the minimal holographic screen can store only one byte of
information while in the thermodynamic limit the area law is corrected by a
logarithmic term.Comment: 18 pages, 4 figures; v2 additional references; v3 shortened version
in press as invited contribution to "Black hole Physics'', special issue of
Advances of High Energy Physics edited by X. Zeng, C. Corda and D. Che