Ghost condensation and a consistent infrared modification of gravity

By N. Arkani-Hamed, Hsin-Chia Cheng, M. Luty, S. Mukohyama. 2003

1,025 citations recorded by the source corpus.

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

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/cc5ce7b088bff562e74920fbb73b706c2470ea19

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Citations in the corpus

Beyond the Cosmological Standard Model (2014, positive): “Another model which has attracted considerable attention is the ghost condensate [445], which can be used to violate the null energy condition and constuction bouncing cosmologies [239, 446, 447].”
On the consistency relation of the three-point function in single-field inflation (2007, background): “Notice that this Lagrangian is very similar to the Lagrangian of the ghost condensate [2, 24].”
Null energy condition and superluminal propagation (2005, background): “These theories include the Fierz-Pauli model, the ghost condensate model [11] and the general class of massive gravities of [13] and are indeed particular cases of the class of scalar theories that we have been focussing on.”
Modified Gravity and Cosmology (2011, background): “In [590] it was shown that if the leading order term in the action has the wrong sign, so that φ is a ghost field, it is still possible to construct a theory that is stable to small fluctuations by including terms that push X to a fixed value, so that”
Dark energy or modified gravity? An effective field theory approach (2012, methodology): “For inflation this includes models such as DBI inflation [15], and for dark energy model it includes models like K-essence [16] and ghost condensates [17].”
Inflation, Cosmic Perturbations and Non-Gaussianities (2013, background): “60 In this case, a ghost condensate [127, 128] may drive us to the correct vacuum, as in the case of tachyon condensate.”
A smooth bouncing cosmology with scale invariant spectrum (2007, background): “For this reason it is important to consider higher derivative terms which in the π Lagrangian give [17, 16] − 1 2 M̄(2) gc(∂ (2)π/a(2))(2) .”
Search for New Physics with Atoms and Molecules (2017, background): “Glenday et al. (2008), Vasilakis et al. (2009), and Heckel et al. (2008) searched for the hypothetical ghost condensate resulting from spontaneous breaking of Lorentz symmetry (Arkani-Hamed et al., 2004; Arkani-Hamed et al., 2005).”
Ekpyrotic and cyclic cosmology (2008, background): “Of course, in light of the singularity theorems of Hawking and Penrose, it is clear that in order to achieve a smooth bounce, one of the assumptions going into these theorems has to give; in the models considered so far this has been the null energy condition (NEC), which is violated by means of a g”