Downconversion of quantum fluctuations of photonic heat current in a circuit

We discuss the nonzero frequency noise of heat current with explicit example energy carried by thermal photons in a circuit. Instead standard circuit modeling that gives convenient way predicting time-averaged current, we describe setup composed two resistors forming baths collections bosonic oscillators. In terms average transport this model leads to identical results conventional one, but besides this, it yields dealing as well. The nonzero-frequency does not vanish equilibrium even at zero temperature, result is known for, e.g., electron tunneling. present modulation method can convert difficult-to-measure high-frequency quantum down frequency.