Cosmological bounds on TeV-scale physics and beyond

Abstract

We study the influence of the fluctuations of a Lorentz invariant and conserved vacuum on cosmological metric perturbations, and show that they generically blow up in the IR. We compute this effect using the Källén-Lehmann spectral representation of stress correlators in generic quantum field theories, as well as the holographic bound on their entanglement entropy, both leading to an IR cut-off that scales as the fifth power of the highest UV scale (in Planck units). One may view this as analogous to the Heisenberg uncertainty principle, which is imposed on the phase space of gravitational theories by the Einstein constraint equations. The leading effect on cosmological observables come from anisotropic vacuum stresses which imply: i) any extension of the standard model of particle physics can only have masses (or resonances)24 TeV, and ii) perturbative quantum field theory or quantum gravity become strongly coupled beyond a UV scale of Λ 1 PeV. Such a low strong coupling scale is independently motivated by the Higgs hierarchy problem. This result, which we dub the cosmological non-constant problem, can be viewed as an extension of the cosmological constant (CC) problem, demonstrating the non-trivial UV-IR coupling and (yet another) limitation of effective field theory in gravity. However, it is more severe than the old CC problem, as vacuum fluctuations cannot be tuned to cancel due to the positivity of spectral densities or entropy. We thus predict that future advances in cosmological observations and collider technology will sandwich from above and below, and eventually discover, new (non-perturbative) physics beyond the Standard Model within the TeV-PeV energy range.

Cosmological constant problem: deflation during inflation

“…It links two completely different and independent calculations. One is implementing quantum effects into a gravitational theory by means of effective quantum field theory and the other solving the modified Friedmann equations (10,11) subject to a simple energy condition (16). The support of both approaches is mutual.…”

Gauss–Bonnet gravity in D = 4 without Gauss–Bonnet coupling to matter: Cosmological implications

“…Such an effect could be exactly what is needed to cure the issues noticed in Ref. 34, where it has been shown that quantum fluctuations in the energy-momentum tensor of matter can cause serious phenomenological problems. The latter could however be avoided provided at high energies exists a field like χ that compensates the effects of the matter fluctuations.…”

Off-shell dark matter: A cosmological relic of quantum gravity

“…If Λ comes from quantum gravitational effects or fundamental discreteness of spacetime [13][14][15], we expect it to be around Planck energy, M P . On the other hand, a priori, Λ can be much smaller than M P , even as low as ∼ 10 TeV, as suggested in large extra dimension models that are constructed to address the hierarchy problem (e.g., [16]), or by the cosmological non-constant problem [17]. However, in this paper we assume Λ H inf , i.e.…”