Gain-and-Loss-Free Metamaterials Exhibiting Non-Hermitian Non-Bloch Effects

The easy implementation of gain and loss provides a fertile ground for the experimental exploration of non-Hermitian (NH) physics. This raises the question of whether NH effects can be realized in a Hermitian system without gain and loss. The interface between coupled Hermitian subsystems naturally lends itself to NH phenomena due to the nonconservative processes occurring there. Nonetheless, endowing such interfaces with rich NH physics remains a significant challenge. Here, we study a junction between a topological model and a conductor model, where the interface can be effectively described by an NH Hamiltonian. Such an NH nature is attributed to the self-energy of the conductor, which functions as a reservoir. Consequently, we demonstrate that the wave propagation along this interface exhibits dissipative nonreciprocity (termed non-Bloch transport), which was previously considered exclusive to NH systems. Moreover, the metamaterialization of tight-binding models is also studied by identifying their equivalent connectivity, thereby enabling the experimental observation of the aforementioned exotic NH interface behavior. Our Letter establishes a conceptually profound framework for engineering NH effects, with broad applicability across both optical and electronic platforms.