Deconfinement in the presence of a Fermi surface

[摘要] U(1) gauge theory of nonrelativistic fermions interacting via compact U(1) gauge fields in the presence of a Fermi surface appears as an effective field theory in low dimensional quantum antiferromagnetism and heavy fermion liquids. We investigate deconfinement of fermions near the Fermi surface in the effective U(1) gauge theory. Our present analysis benchmarks the recent investigation of quantum electrodynamics in two space and one time dimensions (QED(3)) by [Hermele Phys. Rev. B 70, 214437 (2004)]. Utilizing a renormalization group analysis, we show that the effective U(1) gauge theory with a Fermi surface has a stable charged fixed point. Remarkably, the renormalization group equation for an internal charge e [the coupling strength between nonrelativistic fermions and U(1) gauge fields] reveals that the conductivity sigma of fermions near the Fermi surface plays the same role as the flavor number N of massless Dirac fermions in QED(3). This leads us to the conclusion that if the conductivity of fermions is sufficiently large, instanton excitations of U(1) gauge fields can be suppressed owing to critical fluctuations of the nonrelativistic fermions at the charged fixed point. As a result a critical field theory of nonrelativistic fermions interacting via noncompact U(1) gauge fields is obtained at the charged fixed point.

[发布日期] 2005-12-01

[关键词] PHASE-TRANSITIONS;QUANTUM;HEISENBERG;STATES