GAUGE-THEORIES OF HIGH-TC SUPERCONDUCTORS

It is widely believed that the t-J model contains some of the key physics of the high-temperature superconductors. It was proposed that the low-energy physics of the t-J model can be described by a gauge theory of fermions and bosons coupled to a gauge field. The normal state of these fermions was assumed to be a Fermi liquid. We show that perturbation theory around the Fermi-liquid state breaks down at low temperature in a wide class of gauge theories of high-temperature superconductors due to the interaction with an overdamped singular mode arising from the gauge field. This breakdown is present even if the coupling to the gauge field is arbitrary small.