Signature of resonant modes in radiative heat current noise spectrum
Radiative heat transfer between bodies is often dominated by a narrow resonance in the transmission, e.g., due to a cavity mode or a surface excitation. However, this resonant character is not visible in the average heat current. Here, we show that the noise spectrum of heat current can serve as a direct probe of the heat-carrying excitations. Namely, the resonant mode produces a sharp peak in the noise spectrum with a width related to the mode lifetime. We demonstrate that heat transfer in realistic superconducting circuits or between two-dimensional metals can realize our predictions. We also arrive at a general conclusion that the Landauer-type description for the radiative heat transfer breaks down on the level of the noise, while it holds for the average.
J. L. Wise, N. Roubinowitz, W. Belzig, D. M. Basko
Phys. Rev. B 106, 165407 (2022)