Non-Hermitian Skin Effect in Many-Body Thermophotonics

The tight-binding model, foundational in depicting electronic behaviors in solid-state physics, has recently contributed to the understanding of non-Hermitian skin effects in optics, acoustics, and mechanics. However, tight-binding model is primarily built upon scalar nearest couplings, which in turn does not fit to describe the vectorial long-range interactions inherently in thermophotonics. Here, we report a strategy involving many-body radiative interactions in a two-dimensional thermophotonic lattice, and further reveal two types of orthogonal non-Hermitian skin modes in a reciprocal system. For in-plane modes, a pronounced geometry-dependent skin effect manifests at the edges, while for out-of-plane modes, skin effects induced by many-body interactions emerge at the corners instead. Our work provides a pioneering approach for understanding many-body-driven skin effect and unveils a mechanism for unexpected manipulation in thermophotonics.