Holography Stabilizes the Vacuum Energy

Gravitational holography is argued to render the cosmological constant stable against divergent quantum corrections, thus providing a technically natural solution to the cosmological constant problem. Evidence for quantum stability of the cosmological constant is illustrated in a number of examples including bulk descriptions in terms of delocalized degrees of freedom, boundary screen descriptions on stretched horizons, and nonsupersymmetric conformal field theories as dual descriptions of anti–de Sitter space. In an expanding universe, holographic quantum contributions to the stress-energy tensor are argued to be at most of order the energy density of the dominant matter component.