PT-symmetric KdV Solutions and Their Algebraic Extension with Zero-Width Resonances

Abstract

A class of complex breather and soliton solutions to both KdV and mKdV equations are identified with a Pöschl-Teller type PT-symmetric potential. However, these solutions represent only the unbroken-PT phase owing to their isospectrality to an infinite potential well in the complex plane having real spectra. To obtain the broken-PT phase, an extension of the potential satisfying the sl (2,ℝ) potential algebra is mandatory that additionally supports non-trivial zero-width resonances.