  Precisely controlling heat transfer in a quantum mechanical system is
particularly significant for designing quantum thermodynamical devices. With
the technology of experiment advances, circuit quantum electrodynamics (circuit
QED) has become a promising system due to controllable light matter
interactions as well as flexible coupling strengths. In this paper, we design a
thermal diode in terms of the two-photon Rabi model of the circuit QED system.
We find that the thermal diode can not only be realized in the resonant
coupling but also achieve better performance, especially for the detuned
qubit-photon ultrastrong coupling. We also study the photonic detection rates
and their nonreciprocity, which indicates similar behaviors with the
nonreciprocal heat transport. This provides the potential to understand thermal
diode behavior from the quantum optical perspective and could shed new insight
into the relevant research on thermodynamical devices.
