Fig. 3: Floquet channel and topological chiral transport.
From: Engineering topological chiral transport in a flat-band lattice of ultracold atoms
a The Floquet protocol by exchanging the adjacent synthetic flux at the spectroscopic moments. In the first half T/2 period, the system can be described by the Hamiltonian H1; In the second half T/2 period, the system is switched to the Hamiltonian H2. b The theoretical results of optimal flux setting with perfect population transfer. c The calculated optimal half Floquet period time Topt with perfect transfer corresponding to each ϕopt. d The transfer dynamics within the spinor pair with different ϕ1 settings. The subfigure (d1) shows the population transfer under the {ϕ1 = 0.2π, ϕ2 = π} BFL configuration. The last three subfigures (d2–d4) are corresponding to different optimal ϕ1 = ϕopt settings with μ=1, ν = 2, 3, 4, respectively (ϕopt,11 is an imaginary number and thus is irrelevant). e, f The experimental results of the Floquet channel with right and left chiral transport, respectively. For the reason that we mainly observe the chiral current represented by the spinor pair sites An, it is unnecessary to distinguish the micromotions of atomic density in the Bn and Cn sites. So, we have combined the display of Bn and Cn sites by indicating their total density information. g The quasi-energy spectrum of the Floquet channel protocol with Ω = 2π/T. h The extracted \({{\mathcal{D}}}(t)\) curve of experimental result for the chiral transports of the Floquet channels. To indicate the chiral feature, we add ± signs in the front of D(t) to differentiate the leftward and rightward motions. The solid lines show the numerical simulations. The error bars present the standard deviation of measurements
