Simple formulas of directional amplification from non-Bloch band theory

Understand

Green's functions are fundamental quantities that determine the linear responses of physical systems.

• The recent developments of non-Hermitian systems, therefore, call for Green's function formulas of non-Hermitian bands.
• This task is complicated by the high sensitivity of energy spectrums to boundary conditions, which invalidates the straightforward generalization of Hermitian formulas.
• Here, based on the non-Bloch band theory, we obtain simple Green's function formulas of general one-dimensional non-Hermitian bands.