Ghost condensation and a consistent infrared modification of gravity

摘要: We propose a theoretically consistent modification of gravity in the infrared, which is compatible with all current experimental observations. This an analog Higgs mechanism general relativity, and can be thought as arising from ghost condensation — background where scalar field has constant velocity, = M2. The condensate new kind fluid that fill universe, same equation state, ρ −p, cosmological constant, hence drive de Sitter expansion universe. However, unlike it physical excitation, described by systematic effective theory at low energies. excitation unusual low-energy dispersion relation ω2 ~ 4/M2. If coupled to matter directly, gives rise small Lorentz-violating effects long-range 1/r2 spin dependent force. In condensate, energy gravitates not particle physics energy, leading possibility both sources gravitate anti-gravitate. newtonian potential modified oscillatory behavior starting distance scale MPl/M2 time MPl2/M3. opens up number avenues for attacking problems, including inflation, dark energy.