Exploring the Consequences of Non-Hermiticity and PT Symmetry in Electronic Transport

In recent years, non-Hermitian Hamiltonians and their exceptional point (EP) degeneracies have been heavily explored in classical and quantum systems. Coherent electronic transport occurring within a sample material connected to leads is usually described in terms of momentum-dependent, non-Hermitian self-energy operator. And yet, EPs and their consequences in such transport are unexplored. Using a tight-binding model for a spin-preserving sample and spin-mixing contacts connected to leads, we explore the consequences of non-Hermitian Hamiltonian in the spin-space on coherent electronic transport. In particular, we determine the behavior of the electrical conductance near the exceptional points. Our theoretical calculations provide a framework to understand the role of non-Hermiticity, beyond global dissipation, in simple condensed matter systems.