Phenomenologically viable Lorentz-violating quantum gravity

TL;DR

This paper extends Horava's Lifschitz point gravity by removing the detailed balance condition, resulting in a renormalizable model compatible with observations and suitable for precision tests.

Contribution

The authors develop a modified Horava gravity model in 3+1 dimensions that includes all relevant operators and analyzes its classical limit for potential empirical testing.

Findings

Model includes all five marginal and four relevant operators.

Classical equations of motion are derived in ADM-like form.

Framework suitable for detailed precision tests of quantum gravity.

Abstract

Horava's "Lifschitz point gravity" has many desirable features, but in its original incarnation one is forced to accept a non-zero cosmological constant of the wrong sign to be compatible with observation. We develop an extension of Horava's model that abandons "detailed balance", and in 3+1 dimensions exhibit all five marginal (renormalizable) and four relevant (super-renormalizable) operators, as determined by power counting. We also consider the classical limit of this theory, evaluate the Hamiltonian and super-momentum constraints, and extract the classical equations of motion in a form similar to the ADM formulation of general relativity. This puts the model in a framework amenable to developing detailed precision tests.