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?