  The thermoelectric effect in a quantum dot system connected to two electron
reservoirs in the presence of a photon cavity is investigated using a quantum
master equation in the steady-state regime. If a quantized photon field is
applied to the quantum dot system, an extra channel, the photon replica states,
are formed leading to a generation of a photon-induced thermoelectric current.
We observe that the photon replica states contribute to the transport
irrespective of the direction of the thermal gradient. In the off-resonance
regime, when the photon energy is smaller than the energy difference between
the lowest states of the quantum dot system, a current plateau is seen for
strong electron-photon coupling. In the resonant regime, an inversion of
thermoelectric current emerges due to the Rabi-splitting. Therefore, the photon
field can change both the magnitude and the sign of the thermoelectric current
induced by the temperature gradient in the absence of a voltage bias between
the leads.
