Abstract
When a physical system is subjected to a strong external multi-frequency drive, its dynamics can be conveniently represented in the multi-dimensional Floquet lattice. The number of the Floquet lattice dimensions equals the number of {\em irrationally}-related drive frequencies, and the evolution occurs in response to a built-in effective "electric" field, whose components are proportional to the corresponding drive frequencies. The mapping allows to engineer and study temporal analogs of many real-space phenomena. Here we focus on the specific example of a two-level system under two-frequency drive that induces topologically nontrivial band structure in the 2D Floquet space. The observable consequence of such construction is quantized pumping of energy between the sources with frequencies ω₁ and ω₂. When the system is initialized into a Floquet band with the Chern number C, the pumping occurs at the rate P₁₂ = -P₂₁= (C/2π)ℏ ω₁ω₂, an exact counterpart of the transverse current in a conventional topological insulator.