Paul Eyméoud | Searcharxiv

arXiv2016

Mixed electrical-heat noise spectrum in a quantum dot

Using the Keldysh Green function technique, we calculate the finite-frequency correlator between the electrical current and the heat current flowing through a quantum dot connected to reservoirs. At equilibrium, we find that this quantity, called mixed noise, is linked to the thermoelectric ac-conductance by the fluctuation-dissipation theorem. Out-of-equilibrium, we discuss its spectrum and find evidence of the close relationship between the mixed noise and the thermopower. We study the spectral coherence and identify the conditions to have a strong correlation between the electrical and heat currents. The change in the spectral coherence due to the presence of a temperature gradient between the reservoirs is also highlighted.

cond-mat.mes-hall↗

arXiv2015

Correlations between charge and heat currents in an interacting quantum dot

We consider an interacting quantum dot connected to two reservoirs driven at distinct voltage/temperature and we study the correlations between charge and heat currents first as a function of the applied voltage bias, and second as a function of the temperature gradient between the two reservoirs. The Coulomb interactions in the quantum dot are treated using the Hartree approximation and the dot occupation number is determined self-consistently. The correlators exhibit structures in their voltage dependency which are highly non-linear when the coupling between the dot and the reservoirs is weak, and their behavior with temperature is non-monotonous. Moreover the sign of heat cross-correlator can change contrary to what happens with the charge cross-correlator which is always negative. The presence of Coulomb interactions enlarges the domain of voltage in which the heat cross-correlator is negative.

cond-mat.mes-hall↗