Bender et al. [Phys. Rev. Lett. 80, 5243 (1998)] have developed PT-symmetric quantum theory as an extension of quantum theory to non-Hermitian Hamiltonians. We show that when this model has a local PT symmetry acting on composite systems, it violates the nonsignaling principle of relativity. Since the case of global PT symmetry is known to reduce to standard quantum mechanics A. Mostafazadeh [J...

We report on the chemical adsorption mechanism of atomic oxygen on the Pt(111) surface using angle-resolved-photoemission spectroscopy (ARPES) and density functional calculations. The detailed band structure of Pt(111) from ARPES reveals that most of the bands near the Fermi level are surface-states. By comparing band maps of Pt and O/Pt, we identify that dxz (dyz) and dz(2) orbitals are strong...

The concept of parity-time (PT) symmetry in the field of optics has been intensively explored. This study shows the absence of exceptional points in a three-dimensional system composed of a square waveguide array with diagonally-balanced gain/loss distribution. More specifically, we show that an array of four coupled waveguides supports eight fundamental propagation supermodes, four of which ar...

We briefly explain some simple arguments based on pseudo Hermiticity, supersymmetry and PT -symmetry which explain the reality of the spectrum of some non-Hermitian Hamiltonians. Subsequently we employ PT -symmetry as a guiding principle to construct deformations of some integrable systems, the Calogero-Moser-Sutherland model and the Korteweg deVries equation. Some properties of these models ar...

In 1998, Bender and Boettcher found that a wide class of Hamiltonians, even though non-Hermitian, can still exhibit entirely real spectra provided that they obey parity-time requirements or PT symmetry. Here we demonstrate experimentally passive PT-symmetry breaking within the realm of optics. This phase transition leads to a loss induced optical transparency in specially designed pseudo-Hermit...

The PT symmetric version of the generalised Ginocchio potential, a member of the general exactly solvable Natanzon potential class is analysed and its properties are compared with those of PT symmetric potentials from the more restricted shape-invariant class. It is found that the PT symmetric generalised Ginocchio potential has a number of properties in common with the latter potentials: it ca...

We reflect real spectra of new logarithmic model PT-symmetry operators with singular and non-singular in nature. also notice the iso-spectral nature between inverted noninverted potentials. Present numerical results give good agreement previous results.

One of the fundamental axioms of quantum mechanics is associated with the Hermiticity of physical observables1. In the case of the Hamiltonian operator, this requirement not only implies real eigenenergies but also guarantees probability conservation. Interestingly, a wide class of non-Hermitian Hamiltonians can still show entirely real spectra. Among these are Hamiltonians respecting parity–ti...

We show that the formalism of supersymmetry (SUSY), when applied to parity-time (PT ) symmetric optical potentials, can give rise to refractive index landscapes with altogether nontrivial properties. In particular, we find that the presence of gain and loss allows for arbitrarily removing bound states from the spectrum of a structure. This is in stark contrast to the Hermitian case, where the S...

We experimentally demonstrate single longitudinal mode operation in microring laser using the concept of PT symmetry. A PT-symmetric coupled resonator arrangement can considerably enhance the maximum achievable gain of single mode microring cavity. The method is broadband thus work well for inhomogenously broadened gain mediums. It doesn’t rely on any additional component to ensure its mode sel...