Saturation of thermal and spin conductances in a dissipative superfluid junction

TL;DR

This study experimentally demonstrates that dissipation can induce and saturate thermal and spin conductances in a superfluid fermionic junction, reaching universal quantum limits and offering new control methods for quantum transport.

Contribution

It reveals dissipation-induced transport phenomena in superfluid junctions, showing conductance saturation at universal quantum levels, a novel insight into open quantum system behavior.

Findings

Dissipation induces measurable thermal and spin transport.

Transport conductances saturate at universal quantum limits.

Similar behavior observed for different dissipation mechanisms.

Abstract

Fermionic superfluid junctions typically exhibit suppressed thermal and spin transport due to the presence of a pairing gap but allow coherent particle transport. While dissipation generally weakens coherent transport, it can also induce excitations that open other transport channels. In this work, we experimentally study a one-dimensional superfluid junction of strongly interacting fermions with local particle loss and observe dissipation-induced thermal and spin transport that appear to saturate at strong dissipation. Notably, in this regime, the measured thermal and spin conductances are comparable to the universal quantized conductance of one-dimensional ideal Fermi gas. Qualitatively similar behavior is observed for two dissipation mechanisms, either spin-imbalanced or pairwise losses. Our findings provide new insights into transport in interacting open quantum systems and suggest possibilities of dissipative control of spin and thermoelectric transport.