Non-Hermitian topological microwave photonics with synthetic non-Abelian gauges
Year: 2018
Type: preprint
Abstract: Topological phases in spinless non-Hermitian models have been widely studied both theoretically and experimentally in some artificial materials using photonics, phononics and magnon. In this work, we investigate the interplay between non-Hermitian loss and gain and non-Abelian gauge potential realized in a two-component superconducting circuit. In our model, the non-Hermiticity along only gives rise to trivial gain and loss to the states; while the non-Abelian gauge along gives rise to flying butterfly spectra and associated edge modes, which in photonics can be directly measured by the intensity of photons at the boundaries. These two terms do not commute, and their interplay can give rise to several intriguing non-Hermitian phases, including the fully gapped quantum spin Hall (QSH) phase, gapless QSH phase, trivial gapped phase and gapless metallic phase. The bulk-edge correspondence is absent and we find that during the closing of energy gap in the gapped QSH phase, the system enters the gapless QSH phase regime which still supports two counter-propagating edge modes. We have also unveiled the intriguing role of non-Hermiticity on the chiral symmetry and time-reversal symmetry of the Hermitian models, which can be applied to other physical models.
Source: arXiv (Cornell University)
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2903140787