Entropic Gravity SISSA, Statistical Physics JC Friday 28, 2011 E. Verlinde, arXiv: v2 [hep-th]

F EntropyEntropy

Outlook Background: Holographic Principle (Black Hole Thermodynamics, Entropy Bound) Verlinde argument for an entropic gravity (II principle of dynamics, Newton’s law of gravity) … editorial discussion

Black body radiation

R E A

Toward the holographic principle… 100 bits of information Number of degrees of freedom Ex 3 Quantum field theory V oscillators and n states per oscillator

How many different states can be in a region to describe all the physics inside of it? What is the entropy of the «fundamental system»? A region with boundary of area A is fully described by no more than A/4 degrees of freedom, or about 1 bit of information per Planck area

Outlook Background: Holographic Principle (Black Hole Thermodynamics, Entropy Bound) Verlinde argument for an entropic gravity (II principle of dynamics, Newton’s law of gravity) … editorial discussion

SPACE as a storage of information Holographic screen … nothing yet… Emerged space We further assume the theory has a notion of time and that its dynamics is traslational invariant Energy Stat. Phys. Temperature

Holographic screen Unruh Effect Force and Inertia

Newton’s law of gravity Holographic principle T

(i)The number of degrees of freedom is proportional to the area of the screen (Holographic principle) (ii)The energy is evenly distributed over these degrees of freedom (iii) There is a change of entropy in the emergent direction Bekenstein + Unruh

ɸ is a coarse-graining variable Coarse- Graining Space is emerging! Amount of coarse graining

Dark Energy

Unruh Effect It works for dimensional consistency!

References E. Verlinde ‘On the origin of Gravity and the Newton laws’ S.Gao Comment on "On the Origin of Gravity and the Laws of Newton" A. Chivukula ‘Gravity as an entropic phenomenon’ T. Jacobson, ‘Thermodynamics of Spacetime’ Phys. Rev. Lett. (1995) R. Bousso ‘The holographic principle’ R. Ruffini and H. Ohanian ‘Gravitation and spacetime’