Theoretical seminar | 16 December 2020

The report treats the results of scientific research devoted to exciton phenomena in monolayer materials and their possible influence on high harmonics generation (HHG). A novel analytical method for calculating discrete spectrum of a linear operator is to be discussed along with the analysis of HHG in monolayer crystals with out-of-plane external field applied.

Topological photonics in the quantum regime promises to protect the entanglement of quantum states from scattering on defects and can be used as a perspective approach for potential applications in quantum communication and computation. In this talk, I consider the two-photon topological phase induced by interactions including the effective density-dependent coupling in a one-dimensional array of qubits.

Hermitian systems have a specific scattering regime, called the bound state in the continuum, which potentially has an infinitely high Q-factor and, thus, applicability for the light localization, storage, as well as sensors and low-threshold lasers. However, since in reality all materials have finite material losses, true bound states in the continuum cannot be achieved in non-Hermitian systems. The proposed dissertation is aimed to investigate a new class of bound states in the continuum in non-Hermitian systems of general form.

Arrays of carbon nanotubes exhibit quite unusual properties in comparison with the individual carbon nanotube. The emergence of a band gap for gapless nanotubes arranged in an array makes armchair-type nanotubes interesting from the theoretical perspective, even though there are quite a few experimental papers devoted to this topic.