Horava gravity

Matt Visser

Horava gravity is a recent (Jan 2009) idea for trying to develop a quantum field theory of gravity. It is not string theory, nor loop quantum gravity, but is instead a continuum quantum field theory that breaks Lorentz invariance at ultra-high (trans-Planckian) energies, while retaining Lorentz invariance at low and medium energies. The challenge is to keep the symmetry breaking controlled and small - small enough to be compatible with experiment and observation. I will give a very general overview of what is going on in this field, paying particular attention to the disturbing role of the scalar graviton.