Downconversion of quantum fluctuations of photonic heat current in a circuit

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

Automated summary

This article discusses the nonzero-frequency noise of heat current using the example of thermal photons in a circuit. A setup with two resistors forming heat baths composed of bosonic oscillators is described, providing a convenient way to deal with noise. The method presented in the article can convert high-frequency quantum noise into zero frequency for easier measurement.