ΔT Noise as a Robust Diagnostic for Chiral, Helical and Trivial Edge Modes

In this article we demonstrate that ΔT noise provides a sensitive, practical probe for distinguishing chiral edge modes from topological helical and trivial (non-topological) helical edge transport. Measured under zero-current conditions, ΔT noise reveals contrasts that conventional conductance measurements typically miss. Crucially, ΔT requires no external energy input in the form of an applied voltage bias, yet encodes the same intrinsic information that shot noise yields in the zero-temperature, finite-bias limit, without the distorting effects of Joule heating. This absence of bias-induced heating makes ΔT noise both more precise and more reliable than conventional shot-noise approaches. Moreover, the diagnostic power of ΔT noise persists at finite frequencies $ω$ too. The frequency-dependent signal ΔT(ω) exhibits distinctive spectral signatures (including sign changes) that further enhance its utility as an experimentally accessible fingerprint of edge-mode topology.