# What is relation between Holographic principle and Hologram?

What is relation between Holographic principle and Hologram?

The holographic principle is a property of quantum gravity and string theories which states that the description of a volume of space can be thought of as encoded on a boundary to the region—preferably a light-like boundary like a gravitational horizon.

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## 1 Answer

They are pretty much unrelated concepts.

The only similarity is that both the holographic principle and the way holograms work can be described as encoding the information necessary to reconstruct an $N$-dimensional view on an $N-1$-dimensional surface. But beyond that qualitative description, there are not any meaningful similarities.

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There is a slight similarity in that the encoding of the extra dimension is by nonlocal Fourier transform looking things, and this was the motivation for thename, although how precise the analogy is I don't know. – Ron Maimon Sep 14 '12 at 20:29
It would be enlightening to have a statement somewhere which does make the analogy between optical holography and gravitational "holography" as precise as possible, but then highlights all the ways in which they are different. That is, you'd talk about the physics of holographic recording and holographic reconstruction, and about the mapping from bulk to boundary and vice versa, and then (somehow!) you'd comment on whether "reference beam" and "reconstruction beam" have any conceptual analogies in AdS/CFT and its relatives. – Mitchell Porter Oct 1 '12 at 2:46