Floquet Topological Polaritons in Semiconductor Microcavities

We propose and model Floquet topological polaritons in semiconductor microcavities, using the interference of frequency detuned coherent fields to provide a time periodic potential. For arbitrarily weak field strength, where the Floquet frequency is larger than the relevant bandwidth of the system, a Chern insulator is obtained. As the field strength is increased, a topological phase transition is observed with an unpaired Dirac cone proclaiming the anomalous Floquet topological insulator. As the relevant bandwidth increases even further, an exotic Chern insulator with flat band is observed with unpaired Dirac cone at the second critical point. Considering the polariton spin degree of freedom, we find that the choice of field polarization allows oppositely polarized polaritons to either co-propagate or counter-propagate in chiral edge states.Comment: Accepted by PR

Characterization of the chloroplast genome of Verbena officinalis Linn. (Verbenaceae) and its phylogenetic analysis

Verbena officinalis has a long history as a source plant in traditional Chinese medicine. This study adopted next-generation sequencing technology in order to determine complete chloroplast genome of V. officinalis. The results of this investigation showed the chloroplast genome of V. officinalis was 153,286 bp in length, including a pair of inverted repeat (IR) regions (each 25,825 bp), separated by a large single-copy region (LSC) of 84,316 bp and a small single-copy region (SSC) of 17,320 bp, and the overall GC contents of the chloroplast genome was 39.04%. Additionally, we annotated 83 genes, including 48 protein-coding genes, 31 tRNA genes, and 4 rRNA genes. By creating the phylogenetic tree, relationship between V. officinalis and relevant species was discussed, and the result proved that V. officinalis was closely related to Avicennia marina. The findings of the study will serve as a stepping stone for follow-up researches regarding its chloroplast genome

Quasiperiodic Floquet-Thouless Energy Pump

Recent work [M. H. Kolodrubetz et al, PRL 120, 150601] has demonstrated that periodically driven one-dimensional fermionic systems can support quantized energy pumping resulting from an adiabatic modulation of a second parameter. In this work, we explore this topological Floquet-Thouless energy pump in the quasiperiodic driving regime where the parametric driving occurs at finite frequency. We show that quantization of energy pumping persists for finite ramping frequencies, as long as they are incommensurate with the driving frequency, and the system remains localized by spatial disorder. Thus, the topological Floquet-Thouless energy pump is stable beyond the adiabatic regime, occupying a finite region of parameter space. Phase transitions away from these topological phases are accompanied by delocalization in position space, photon number (energy) space, or both. Using a dimensional reduction scheme, we demonstrate that a related phase can be realized with a cavity-qubit system driven by two incommensurate modes