Topological nodal points on two-leg superconducting circuits

As the connection of different topological quantum phases, gapless systems have attracted much attention. The emergence nodal points is typically observed in with two or three dimensions, whereas we demonstrate existence a model that lies between one and dimensions this paper. Superconducting circuits as an essential All-solid state device become promising platform for macro-controlling effect. Recently, experimental achievements enabled realization tunable coupling strengths transmon qubits implementation one-dimensional Su-Schrieffer-Heeger (SSH) model[Li X <i>et al.</i> 2018 <i>Phys. Rev. Appl.</i> <b>10</b> 054009]. Based on work, present two-leg SSH implemented superconducting Firstly, which are coupled their nearest-neighbor sites by capacitors designed For constructing model, alternating-current magnetic fluxes introduced to drive each qubit. Then types phase boundaries discovered corresponding energy spectrums diagram obtained We distinct insulating phases characterized winding number ±1, edge states also exhibit characteristics. Furthermore, properties discussed. represent Bloch vector field <i>k</i> space kinks first type boundaries. These possess charges 1 -1, respectively. While second topologically trivial. results provide new route explore novel state, ladder physical system, point semimetal.