Crystal gravity

SciPost Physics, vol. 13

Abstract

We address a subject that could have been analyzed century ago: how does the universe of general relativity look like when it would have been filled with solid matter? Solids break spontaneously the translations and rotations of space itself. Only rather recently it was realized in various context that the order parameter of the solid has a relation to Einsteins dynamical space time which is similar to the role of a Higgs field in a Yang-Mills gauge theory. Such a "crystal gravity" is therefore like the Higgs phase of gravity. The usual Higgs phases are characterized by a special phenomenology. A case in point is superconductivity exhibiting phenomena like the Type II phase, characterized by the emergence of an Abrikosov lattice of quantized magnetic fluxes absorbing the external magnetic field. What to expect in the gravitational setting? The theory of elasticity is the universal effective field theory associated with the breaking of space translations and rotations having a similar status as the phase action describing a neutral superfluid. A geometrical formulation appeared in its long history, similar in structure to general relativity, which greatly facilitates the marriage of both theories. With as main limitation that we focus entirely on stationary circumstances -- the dynamical theory is greatly complicated by the lack of Lorentz invariance -- we will present a first exploration of a remarkably rich and often simple physics of "Higgsed gravity".

Authors 3

1. Jan Zaanen Aachen Institute-Lorentz for Theoretical Physics

   Leiden University

   Affiliation as printed

   Lorentz Institute

   The Institute Lorentz for Theoretical Physics, Leiden University, Leiden, The Netherlands

2. Floris Balm Aachen Institute-Lorentz for Theoretical Physics

   Leiden University

   Affiliation as printed

   Lorentz Institute

   The Institute Lorentz for Theoretical Physics, Leiden University, Leiden, The Netherlands

3. Aron Beekman

   Keio University

   Affiliation as printed

   Keio University

   Department of Physics and Research and Education Center for Natural Sciences, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan