If Universe a Hologram, Is 3D an Illusion?

That the universe is not what it appears to be is not a new thought to comprehend. However imagining the universe as a big giant hologram with the third dimension an illusion, could be disorienting. A group of mathematicians and physicists have done just that.

The researchers have shown correspondence between three dimensional gravitational phenomenon and two dimensional quantum phenomenon in flat space, which was earlier considered possible only in extreme theoretical spaces called the anti-di-sitter spaces. The universe too can mathematically show such a correspondence, and thus behave like a hologram.

Researchers, who hypothesized that the universe could be understood as a hologram, proved it by showing that entropy of entanglement can take the same value in calculations involving gravitation and quantum theories. Entropy of entanglement is a measure of entanglement of particles in a quantum field.

"This calculation affirms our assumption that the holographic principle can also be realized in flat spaces. It is evidence for the validity of this correspondence in our universe. The fact that we can even talk about quantum information and entropy of entanglement in a theory of gravity is astounding in itself and would hardly have been imaginable only a few years back. That we are now able to use this as a tool to test the validity of the holographic principle, and that this test works out, is quite remarkable", said Daniel Grumiller of Vienna University of Technology.

Researchers clarified their calculations does not imply that we are actually living in a hologram. It only shows the mathematically possibility of such an understanding for the universe.