Physics Maths Engineering
Steering Edge Currents through a Floquet-Topological Insulator
Helena Drueke,
Helena Drueke
Institute of Physics, University of Rostock, 18051 Rostock, Germany
Dieter Bauer
Dieter Bauer
Institute of Physics, University of Rostock, 18051 Rostock, Germany
Related Subjects
Abstract
"Periodic driving may cause topologically protected, chiral transport along edges of a 2D lattice that, without driving, would be topologically trivial. We study what happens if one adds a different on-site potential along the diagonal of such a 2D grid. In addition to the usual bulk and edge states, the system then also exhibits doublon states, analogous to two interacting particles in one dimension. A particle initially located at an edge propagates along the system's boundary. Its wavefunction splits when it hits the diagonal and continues propagating simultaneously along the edge and the diagonal. The strength of the diagonal potential determines the ratio between both parts. We show that for specific values of the diagonal potential, hopping onto the diagonal is prohibited so that the system effectively separates into two triangular lattices. For other values of the diagonal potential, we find a temporal delay between the two contributions traveling around and through the system. This behavior could enable the steering of topologically protected transport of light along the edges and through the bulk of laser-inscribed photonic waveguide arrays."
Key Questions
What is the central focus of the study on periodic driving and chiral transport in a 2D lattice?
The study focuses on how periodic driving can induce topologically protected, chiral transport along the edges of a 2D lattice that would otherwise be topologically trivial. It investigates the effects of adding a diagonal on-site potential to the lattice, which introduces new phenomena such as doublon states and split wavefunction propagation along the edge and diagonal.
What are doublon states, and how do they arise in this system?
Doublon states are analogous to two interacting particles in one dimension and arise in the system due to the addition of a diagonal on-site potential. These states coexist with the usual bulk and edge states, adding complexity to the system's dynamics and influencing the propagation of particles along the lattice.
How does the diagonal potential affect particle propagation in the lattice?
When a particle initially located at an edge propagates along the boundary, its wavefunction splits upon encountering the diagonal potential. The particle then propagates simultaneously along the edge and the diagonal. The strength of the diagonal potential determines the ratio of the wavefunction's split, influencing the particle's path and behavior.
What happens when the diagonal potential takes specific values?
For specific values of the diagonal potential, hopping onto the diagonal is entirely prohibited. This effectively separates the system into two triangular lattices, altering the transport dynamics. For other values, a temporal delay occurs between the wavefunction contributions traveling around the edge and through the diagonal, enabling controlled steering of particle transport.
What are the potential applications of this study?
The study's findings could enable the steering of topologically protected transport of light in photonic waveguide arrays. By controlling the diagonal potential, one can manipulate the propagation of light along the edges and through the bulk of the lattice, with potential applications in optical computing, signal processing, and quantum simulations.
