After Leonard Susskind

Leonard Susskind

Leonard Susskind is the Felix Bloch Professor of Theoretical Physics at Stanford University. His research interests include string theory, quantum field theory, quantum statistical mechanics and quantum cosmology...

 proposed the black hole complementarity

Black hole complementarity

Black hole complementarity is a conjectured solution to the black hole information paradox, proposed by Leonard Susskind and Gerard 't Hooft.Ever since Stephen Hawking suggested information is lost in evaporating black hole once it passes through the event horizon and is inevitably destroyed at the...

 conjecture for black hole

Black hole

A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...

s in quantum gravity

Quantum gravity

Quantum gravity is the field of theoretical physics which attempts to develop scientific models that unify quantum mechanics with general relativity...

, he realized it would also apply to a de Sitter universe

De Sitter universe

A de Sitter universe is a cosmological solution to Einstein's field equations of General Relativity which is named after Willem de Sitter. It models the universe as spatially flat and neglects ordinary matter, so the dynamics of the universe are dominated by the cosmological constant, thought to...

 with a positive cosmological constant

Cosmological constant

In physical cosmology, the cosmological constant was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe...

 with the cosmological horizon in place of the event horizon

Event horizon

In general relativity, an event horizon is a boundary in spacetime beyond which events cannot affect an outside observer. In layman's terms it is defined as "the point of no return" i.e. the point at which the gravitational pull becomes so great as to make escape impossible. The most common case...

. The region within the horizon is the causal patch, and it is self-contained. This means we may neglect what happens beyond the cosmological horizon. A consequence of this radical conjecture is that the total number of states of the universe is finite.

See also

• Black hole complementarity
  Black hole complementarity
  Black hole complementarity is a conjectured solution to the black hole information paradox, proposed by Leonard Susskind and Gerard 't Hooft.Ever since Stephen Hawking suggested information is lost in evaporating black hole once it passes through the event horizon and is inevitably destroyed at the...
  
  
• de Sitter space
  De Sitter space
  In mathematics and physics, a de Sitter space is the analog in Minkowski space, or spacetime, of a sphere in ordinary, Euclidean space. The n-dimensional de Sitter space , denoted dS_n, is the Lorentzian manifold analog of an n-sphere ; it is maximally symmetric, has constant positive curvature,...