  The energetic properties of electron transport in mesoscopic and nanoscale
conductors is of large current interest. Here we theoretically investigate the
possibility of probing fluctuations of charge and heat currents as well as
their mixed correlations via fluctuations of the temperature and
electrochemical potential of a probe coupled to the conductor. Our particular
interest is devoted to the charge and energy noise stemming from
time-dependently driven nanoelectronic systems designed for the controlled
emission of single electrons, even though our setup is appropriate for more
general AC driving schemes. We employ a Boltzmann-Langevin approach in order to
relate the frequency-dependent electrochemical potential and temperature
fluctuations in the probe to the bare charge and energy current fluctuations
emitted from the electron source. We apply our findings to the prominent
example of an on-demand single-electron source, realized by a driven mesoscopic
capacitor in the quantum Hall regime. We show that neither the background
fluctuations of the probe in the absence of the working source, nor the
fluctuations induced by the probe hinder the access to the sought-for direct
source noise for a large range of parameters.
