PT symmetry and exceptional points in metamaterials

[摘要] Parity-Time (PT) symmetry has recently received much attention as a promising alternative to the condition of Hermiticity. PT symmetric systems have two distinct phases where behaviour is split between Hermitian evolution where it has real eigenvalues and non-Hermitian evolution where it has complex eigenvalues.At the crossover between these two phases, there is an exceptional point: a special kind of eigenvalue degeneracy unique to non-Hermitian system which can result in interesting properties. In this thesis, we will first review the field of metamaterials and show how they can be used to design electromagnetic potentials. We will also review the current understanding of PT symmetry and its associated effects in electromagnetism.We will then develop a new form of parity operator which can be used in conjunction with the time-reversal operator to derive new conditions on the constitutive matrix.ThisparityoperatorwillthenbeusedtounderstandthelinkbetweenPTsymmetryand exceptional points with experimental support from a metamaterial system. We will additionally look at some other applications of PT symmetry, specifically in the context of lasing and absorption,and attempt to design a structure which uses this symmetry.

[发布机构] University:University of Birmingham;Department:School of Physics and Astronomy

[关键词] Q Science;QC Physics