  We briefly review the history and current status of models of particle
interactions in which massless mediators are given, not by fundamental gauge
fields as in the Standard Model, but by composite degrees of freedom of
fermionic systems. Such models generally require the breaking of Lorentz
invariance. We describe schemes in which the photon and the graviton emerge as
Goldstone bosons from the breaking of Lorentz invariance, as well as
generalizations of the quantum Hall effect in which composite excitations yield
massless particles of all integer spins. While these schemes are of limited
interest for the photon (spin 1), in the case of the graviton (spin 2) they
offer a possible solution to the long-standing UV problem in quantum linear
gravity.
