  The state of electrons injected onto the surface of the Fermi sea depends on
temperature. The state is pure at zero temperature and is mixed at finite
temperature. In the case of a single-electron injection, such a transformation
can be detected as a decrease in shot noise with increasing temperature. In the
case of a multi-electron injection, the situation is more subtle. The mixedness
helps the development of quantum-mechanical exchange correlations between
injected electrons, even if such correlations are absent at zero temperature.
These correlations enhance the shot noise, what in part counteracts the
reduction of noise with temperature. Moreover, at sufficiently high
temperatures, the correlation contribution to noise predominates over the
contribution of individual particles. As a result, in the system of $N$
electrons, the apparent charge (which is revealed via the shot noise) is
changed from $e$ at zero temperature to $Ne$ at high temperatures. It looks
like the exchange correlations glue up electrons into one particle of total
charge and energy. This point of view is supported by both charge noise and
heat noise. Interestingly, in the macroscopic limit, $N\to \infty$, the
correlation contribution completely suppresses the effect of temperature on
noise.
