Gain-gain and gain-lossless PT-symmetry broken from PT-phase diagram

Detecting Broken PT-Symmetry

A fundamental problem in the theory of PT-invariant quantum systems is to determine whether a given system “respects” this symmetry or not. If not, the system usually develops non-real eigenvalues. It is shown in this contribution how to algorithmically detect the existence of complex eigenvalues for a given PT-symmetric matrix. The procedure uses classical results from stability theory which q...

Broadband mixing of PT-symmetric and PT-broken phases in photonic heterostructures with a one-dimensional loss/gain bilayer

Combining loss and gain components in one photonic heterostructure opens a new route to efficient manipulation by radiation, transmission, absorption, and scattering of electromagnetic waves. Therefore, loss/ gain structures enabling PT-symmetric and PT-broken phases for eigenvalues have extensively been studied in the last decade. In particular, translation from one phase to another, which occ...

Nonlocality in PT-symmetric waveguide arrays with gain and loss.

We demonstrate that light propagation in waveguide arrays that include PT-symmetric structures can exhibit strongly nonlocal sensitivity to topology of the array at fixed other parameters. We consider an array composed of lossless waveguides, that includes a pair of PT-symmetric waveguides with balanced gain and loss, and reveal that PT-symmetry breaking thresholds are different for planar and ...

Gain-driven discrete breathers in PT-symmetric nonlinear metamaterials.

We introduce a one-dimensional parity-time- (PT-)symmetric nonlinear magnetic metamaterial consisting of split-ring dimers having both gain and loss. When nonlinearity is absent we find a transition between an exact to a broken PT phase; in the former, the system features a two band gapped spectrum with shape determined by the gain and loss coefficients as well as the interunit coupling. In the...

Explicit definition of PT symmetry for nonunitary quantum walks with gain and loss