Two-Dimensional Non-Fermi-Liquid Metals: A Solvable Large-N Limit

• Autores: Aguilera Damia, Jeremías; Kachru, Shamit; Raghu, Srinivas; Torroba, Gonzalo
• Año de publicación: 2019
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: non-fermi liquids; large N limit; quantum critical point
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Significant effort has been devoted to the study of “non-Fermi-liquid” (NFL) metals: gapless conducting systems that lack a quasiparticle description. One class of NFL metals involves a finite density of fermions interacting with soft order parameter fluctuations near a quantum critical point. The problem has been extensively studied in a large-N limit (N corresponding to the number of fermion flavors) where universal behavior can be obtained by solving a set of coupled saddle-point equations. However, a remarkable study by Lee revealed the breakdown of such approximations in two spatial dimensions. We show that an alternate approach, in which the fermions belong to the fundamental representation of a global SUðNÞ flavor symmetry, while the order parameter fields transform under the adjoint representation (a “matrix large-N” theory), yields a tractable large N limit. At low energies, the system consists of an overdamped boson with dynamical exponent z ¼ 3 coupled to a non-Fermi-liquid with self-energy ΣðωÞ ∼ ω2=3 , consistent with previous studies.
Fil: Aguilera Damia, Jeremías. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Kachru, Shamit. University of Stanford; Estados Unidos
Fil: Raghu, Srinivas. Slac National Accelerator Laboratory; Estados Unidos. University of Stanford; Estados Unidos
Fil: Torroba, Gonzalo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina