Related papers: Fundamental issues with light propagation through …
Electromagnetic materials possessing parity-time symmetry have received significant attention since it was discovered that the eigenmodes of these materials possess either real-frequency eigenvalues or the eigenfrequencies appear in…
We show that the time-averaged Poynting vector in parity-time (PT ) symmetric coupled waveguides is always positive and cannot explain the stopped light at exceptional points (EPs). In order to solve this paradox, we must accept the fact…
A quench in a Su-Schrieffer-Heeger lattice across the topological boundary initialized with an edge state leads to transport across the chain. We consider such a quench in an effective model in which non-Hermitian components are embedded in…
Plasmonic many-particle systems with precisely tuned resonances and coupling strengths can exhibit emergent collective properties governed by universal principles. In one-dimensional chains with alternating couplings, known as…
We consider a parity-time ($\mathcal{PT}$-) symmetric waveguide consisting of a localized gain and loss elements separated by a variable distance. The situation is modelled by a Schr\"odiner operator with localized complex…
We analyze the topological properties of a family of generalized Su-Schrieffer-Heeger (SSH) chains and mesh geometries. In both the geometries the usual staggering in the distribution of the two overlap integrals is delayed (in space) by…
The characteristic anti-linear (parity/time reversal, PT) symmetry of non-Hermitian Hamiltonians with real energies is presented as a source of two new forms of solvability of Schr\"{o}dinger's bound-state problems. In detail we describe…
We consider the non-Hermitian, parity-time (PT) symmetric extensions of the one-dimensional Su-Schrieffer-Heeger (SSH) model in the topological non-trivial configuration. We study the properties of the topologically protected edge states,…
We investigate topological and disorder effects in non-Hermitian systems with chiral symmetry. The system under consideration consists in a finite Su-Schrieffer-Heeger chain to which two semi-infinite leads are attached. The system lacks…
We investigate the up-conversion process of broadband light from parametric down-conversion (PDC), focusing on the spatio-temporal spectral properties of the sum-frequency generated (SFG) radiation. We demonstrate that the incoherent…
In this paper we introduce Parity-Time ($\cal PT$) symmetric perturbation to a one-dimensional Lieb lattice, which is otherwise $\cal P$-symmetric and has a flat band. In the flat band there are a multitude of degenerate dark states, and…
Parity-time ($\mathcal{PT}$) symmetric systems are classical, gain-loss systems whose dynamics are governed by non-Hermitian Hamiltonians with exceptional-point (EP) degeneracies. The eigenvalues of a $\mathcal{PT}$-symmetric Hamiltonian…
Using the Maxwell-Bloch equations for resonantly absorbing and amplifying media, we study the temporal dynamics of light propagation through the PT-symmetric structures with alternating loss and gain layers. This approach allows us to…
We study the effect of periodic but commensurate hopping modulation on a Su-Schrieffer-Heeger (SSH) chain with an additional onsite staggered imaginary potential. Such dissipative, non-Hermitian (NH) extension amply modifies the features of…
In order to transport information with topological protection, we reveal and demonstrate experimentally the existence of a characteristic length $L_c$, coined as the transport length, in the bulk size for edge states in one-dimensional…
We investigate a new class of optical mesh periodic structures that are discretized in both the transverse and longitudinal directions. These networks are composed of waveguide arrays that are discretely coupled while phase elements are…
The Su-Schrieffer-Heeger (SSH) model lays the foundation of many important concepts in quantum topological matters. Since it tells one that topological states may be distinguished by abelian geometric phases, a question naturally arises as…
Recent progress on nonlinear properties of parity-time ($\cal PT$-) symmetric systems is comprehensively reviewed in this article. $\cal PT$ symmetry started out in non-Hermitian quantum mechanics, where complex potentials obeying $\cal PT$…
In polymer science, cross-linking of polymer chains yields a substantially modified system compared to the one-dimensional constituent chains, due to the increase of dimensionality and effective seeding by defects (cross-linking sites).…
We study transport properties of an array created by alternating $(a,b)$ layers with balanced loss/gain characterized by the key parameter $\gamma$. It is shown that for non-equal widths of $(a,b)$ layers, i.e., when the corresponding…