Could it be possible that we are living in a two-dimensional space and are just perceiving the third-dimension? Thats what scientists are suggesting in this recent article published in APS Physics. In the article, scientists Arjun Bagchi, Rudranil Basu, Daniel Grumiller, and Max Riegler, show a theoretical mathematical model that proofs the holographic principal developed by physicist Juan Maldacena.

Maldacena’s model only covered exotic spaces with negative curvature, but these new proofs extend the theory to flat spacetime, such as we experience in our universe. Daniel Grumiller from the TU Vienna, Austria has suspected for some time that a correspondence principle could also hold true for our real universe. To test this hypothesis, gravitational theories have to be constructed, which do not require exotic anti-de-sitter spaces, but live in a flat space. For three years, he and his team have been working on that, in cooperation with the University of Edinburgh, Harvard, IISER Pune, the MIT and the University of Kyoto.

“If quantum gravity in a flat space allows for a holographic description by a standard quantum theory, then there must be physical quantities, which can be calculated in both theories – and the results must agree”, says Grumiller. Quantum entanglement must appear in the gravitational theory.

When quantum particles are entangled, they cannot be described individually – they form a single quantum object. The measure for the amount of entanglement in a quantum system is called “entropy of entanglement”. Together, the researchers have shown that the entropy of entanglement takes the same value in flat quantum gravity and in a low dimension quantum field theory.

“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”, says Max Riegler (TU Wien). “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”, says Daniel Grumiller.