  Controlling the transmission of electrical current using a quantum point
contact constriction paved a way to a large variety of experiments in
mesoscopic physics. The increasing interest in heat transfer in such systems
fosters questions about possible manipulations of quantum heat modes that do
not carry net charge(neutral modes). Here, we study the transmission of
upstream neutral modes through a quantum point contact in fractional
hole-conjugate quantum Hall states. Employing two different measurement
techniques, we were able to render the relative spatial distribution of these
chargeless modes with their charged counter-parts. In these states, which were
found to harbor more than one downstream charge mode, the upstream neutral
modes are found to flow with the inner charge mode - as theoretically
predicted. These results unveil a universal upstream heat current structure and
open the path for more complex engineering of heat flows and cooling mechanisms
in quantum nano-electronic devices.
