Is our universe a hologram?
Credit: TU Wien
Is our universe a hologram
To us, the universe looks three dimensional. But one of the theories of theoretical physics challenges this assumption. The “holographic principle” suggests that a mathematical description of the universe actually requires one fewer dimensions than it seems. What we perceive as three dimensional may just be the image of two dimensional processes on a huge cosmic horizon. Now, scientists are taking a closer look at this theory .
Holograms are two-dimensional pictures that appear to the human eye as three-dimensional objects. Some scientists believe that our universe may behave similarly, existing as a sort of all-encompassing hologram.
As explained by Nature World News, “a mathematical description of the Universe actually requires one fewer dimension than it seems” according to the “holographic principle,” which would indicate that what appears to be a 3-D universe may actually “just be the image of 2-D processes on a huge cosmic horizon.”
Prior to this study, scientists looked into this holographic principle by applying their calculations to a universe presenting Anti de Sitter space. Anti de Sitter is the term used to describe space as having a hyperbolic shape, much like a saddle. This hyperbolic space shape behaves, mathematically, as special relativity would predict.
Special relativity is a theory put forth by Albert Einstein to describe the relationship between space and time, and is especially useful when studying very small particles moving at extreme speeds over cosmic distances. The concept of Anti de Sitter space assumes that spacetime itself is hyperbolic in its natural state, in the absence of matter or energy.
A team at the Vienne University of Technology looked at the holographic principle not in the usual Anti de Sitter space framework, but instead applied the principle to flat spacetime, as represents our physical universe.
“Our Universe, in contrast, is quite flat – and on astronomic distances, it has positive curvature,” team member Daniel Grumiller said in a statement.
The team created several gravitational theories that apply to flat space to see if calculations regarding quantum gravity would indicate a holographic description as has occurred in former calculations with theories applied to Anti de Sitter space.
“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,” Grumiller said.
The team found that the amount of quantum entanglement required for gravitational theory models expressed the same value in flat quantum gravity as in a low dimensional field theory, showing that the theory of a holographic universe can be successfully applied to the reality of the relatively flat field of spacetime evident in our universe.
“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” team member Max Riegler said.