2026/03/20 by Sachiraj Mishra, A Rajmohan Dora, Colin Benjamin
#cond-mat.supr-con #cond-mat.mes-hall #hep-ph #math-ph #math.MP #quant-ph
Quantum noise has long served as a powerful probe of quantum transport in mesoscopic junctions. Recently, temperature-driven noise, or ΔT noise, has attracted growing interest due to its presence even in the absence of average charge current. In this work, we investigate a normal metal-insulator-iron-pnictide junction and demonstrate how zero temperature quantum shot noise, finite temperature quantum noise and ΔT noise can discriminate between S++ and S+- pairing symmetries, which are relevant to iron-based superconductors. We introduce ΔT noise as a novel probe for distinguishing between the two pairing symmetries. In contrast to conductance, which exhibits a single peak for both S++ and S+- states with only a difference in magnitude, the ΔT noise reveals qualitatively distinct features: a twin-peak structure for the S++ pairing symmetry and a single-peak profile for the S+- state. A similar symmetry-dependent contrast is observed in both zero temperature quantum shot noise and finite temperature quantum noise, where the S++ state consistently exhibits a twin-peak structure, while the S+- state shows a single-peak response. Our results demonstrate that noise-based measurements form a mutually reinforcing set of probes that enables reliable identification of superconducting gap symmetry in Iron Pnictide superconductors.