Inflation as an amplifier: the case of Lorentz violation

Abstract

Modified gravity theories are supposed to incorporate low-energy quantum-gravity effects and, at the same time, they could shed light into the dark matter and dark energy problems. Here we study a particular modification of general relativity where local Lorentz invariance is spontaneously broken and whose physical effects, despite a decade-long effort, were unknown. We show that, during inflation, this modification produces anisotropies that would generate measurable effects on the Cosmic Microwave Background. Then, by using empirical constraints on the B-mode polarization spectrum, we can estimate that the `coefficient' components absolute value have to be smaller than $10^{-43}$. This is a remarkably strong limit, in fact, it is 29 orders of magnitude better than the best constraints on similar coefficients. Thus, we propose that inflation could stringently test other modified gravity theories.

6 pages

References in corpus (7)

• A Joint Analysis of BICEP2/Keck Array and Planck Data
• Signals for Lorentz Violation in Post-Newtonian Gravity
• Short-range gravity and Lorentz violation
• Tests of Lorentz symmetry in the gravitational sector
• Time-delay and Doppler tests of the Lorentz symmetry of gravity
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Cited by in corpus (15)

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• Signals for Lorentz violation in gravitational waves
• Lorentz and Diffeomorphism Violations in Linearized Gravity
• Gravity with explicit spacetime symmetry breaking and the Standard-Model Extension
• 3+1 Formulation of the Standard-Model Extension Gravity Sector
• Hamiltonian formulation of an effective modified gravity with nondynamical background fields
• Explicit Lorentz violation in a static and spherically-symmetric spacetime
• Explicit spacetime-symmetry breaking and the dynamics of primordial fields
• Is there any symmetry left in gravity theories with explicit Lorentz violation?
• Energy nonconservation and relativistic trajectories: Unimodular gravity and beyond
• Spontaneous Lorentz violation and asymptotic flatness
• Short-range forces due to Lorentz-symmetry violation
• Construction of higher-order metric fluctuation terms in spacetime symmetry-breaking effective field theory
• Testing Lorentz symmetry with space-based gravitational-wave detectors
• Cosmology in the presence of diffeomorphism-violating, nondynamical background fields