The universe as a hologram
Joscha Dutli, Boris Pestoni, University of Zürich
AST 202 The Universe: Contents, Origin, Evolution and Future
May 24, 2016
Premise
• Not everyone will be able to understand the holographic principle. (Leonard Susskind)
Contents
• Black holes: GTR vs QM • Susskind idea • Black holes ➔ universe • Juan Maldecena,
mathematical proof • Just a theory or reality?
Fermilab experiment
What are the information?
• Information: distinction between the fondamental particles that make up the atom in a body and the rest of the universe
What is a black hole?
Black hole information paradox
Sthepen Hawking
• Thermodynamics, general relativity, Hawking radiation
• The information of everything that goes into a black hole will be lost
Leonard Susskind
• Quantum mechanics • Information can’t be lost
Susskind intuition
• Classical physics: a particle can be only in one place at the same time
• Quantum mechanics: a particle can be in two places at the same time
• ➔ Holograpic principle
Holographic principle idea
From black holes to the universe
black hole ➔ universe event horizon ➔ cosmological horizon
The universe is finite
• According to the holographic principle, the universe can be described by a polyhedral surface with 10100 cloves: this means that the universe is not infinite, but only very very big!
Rigorous proof
• Juan Maldecena in 1997, using string theory, mathematically proves what until then was only a conjecture by Susskind and Gerard 't Hooft.
Physical recap of the previous slides
• Black hole: disorder = entropy ~ surface area • Entropy ~ information content => the
information-area connection might be extended to any properly defined spacetime.
• Amount of information in a 3D region ~ 2D surface area
• The total amount of information in the universe is finite
Which one is reality?
• Are we the projection or is the outer surface the projection?
• Which one is reality? • Whatever happens
here, happens there and vice versa ➔ it is our choice to say which is the reality because the mathematics says they’re equivalent
Does the theory match the reality?
• It’s a plausible theory. Is it correct?
• Craig Hogan, Fermilab experiment
Holographic noise
QM: Heisenberg uncertainty principle
Holographic principle: holographic noise
Apparatus
Purpose of the experiment
• 1 interferometer: holographic noise should cause the output of an interferometer to jiggle
• 2 interferometers, one beside the other: holographic noise would be uncorrelated
• 2 nested interferometers: the holographic noise should be correlated and, if the apparatus is big enough, measurable
Results and debate
• They found no jiggle ➔ Hogan concludes that the holographic principle is not a correct theory
• Debate: many physicists don’t believe that the holographic principle would require the existence of a noise ➔ the experiment is useless
Summary
• Holographic principle is a mathematically theory that could correspond to reality
• Unification of gravity and quantum mechanics through string theory.
• If it is true, the universe is finite and the total amount of information in the universe in finite
Thanks for your attention
Questions?