Giant heat flux effect in nonchiral transmission lines

We develop a theory of heat transport in nonchiral transmission lines (TLs) of quantum Hall edge channels coupled to Ohmic contacts that accounts for a dynamical accumulation of charge in the reservoirs. As a consequence, heat transport is driven by charge fluctuations in the heat Coulomb blockade regime. This framework challenges conventional paradigms by revealing a giant heat flux effect—a significant amplification in heat transport arising from nontrivial fluctuation-dissipation relations. Through a Langevin-based approach, we derive the effective noise power in the chiral currents, which underlies this enhanced heat flux. Our findings predict clear experimental signatures unique to nonchiral TLs, as well as provide insights into finite-frequency effects, showing crossovers to more conventional diffusive behavior. This work offers a perspective on feedback mechanisms in quasi-one-dimensional heat transport with implications for dissipation control in low-dimensional quantum systems.