Colored delta- T noise in fractional quantum Hall liquids

Photons are emitted or absorbed by a nanocircuit under both equilibrium and nonequilibrium situations. Here, we focus on the nonequilibrium situation arising due to a temperature difference between the leads of a quantum point contact and study the finite-frequency (colored) noise. We explore this delta-$T$ noise in the finite-frequency regime for two systems: conventional conductors described by Fermi liquid scattering theory and the fractional quantum Hall system at Laughlin filling fractions, described by the chiral Luttinger liquid formalism. We study the emission noise, its expansion in the temperature difference (focusing on the quadratic component), as well as the excess emission noise defined with respect to a properly chosen equilibrium situation. The behavior of these quantities is markedly different for the fractional quantum Hall system compared to Fermi liquids, signaling the role of strong correlations of the fractional quantum Hall effect and the importance of the nature of the charge carriers tunneling across the junction.