%0 Journal Article
%A Sánchez Soto, Luis Lorenzo
%A Monzón Serrano, Juan José
%T Invisibility and PT Symmetry: A Simple Geometrical Viewpoint
%D 2014
%@ 2073-8994
%U https://hdl.handle.net/20.500.14352/35546
%X We give a simplified account of the properties of the transfer matrix for a complex one-dimensional potential, paying special attention to the particular instance of unidirectional invisibility. In appropriate variables, invisible potentials appear as performing null rotations, which lead to the helicity-gauge symmetry of massless particles. In hyperbolic geometry, this can be interpreted, via Möbius transformations, as parallel displacements, a geometric action that has no Euclidean analogy.
%~