Fig. 4: Implementation of the nontrivial gauge field in synthetic triangular lattices.
From: Multidimensional synthetic chiral-tube lattices via nonlinear frequency conversion
a Three-pump configuration used to induce three orders of coupling. b The implemented synthetic frequency lattice with the first, third, and fourth orders of coupling. c The mapping of b to a two-dimensional triangular lattice where the flux in each cell is zero. d–f Our specially designed scheme for implementing nonzero flux by adding an extra pump (A3) and tailoring the pump phases
