Non-unitary Quantum Materials
Novel functions from the edge of the quantum world
Novel categories of quantum materials and electronic devices can be obtained by pipelining the evolution of electron quantum states as described by Schrödinger’s equation with inelastic processes that interrupt the coherent propagation of electrons, as now presented in Nano Express 2 014008 (2021) (open access).
These materials and devices reside in the fascinating transition regime between quantum mechanics and classical physics. The materials are designed such that a nonreciprocal unitary state evolution, achieved by a broken inversion symmetry, is interrupted by individual inelastic scattering events caused by defects. Two-terminal non-unitary quantum devices, for example, feature nonreciprocal conductance in linear response. Thus, they are exemptions to Onsager’s reciprocal relation, and they challenge the second law of thermodynamics. Materials and metamaterials featuring such functionalities may be realized by embedding such nanostructures into their unit cells.