Experimental Observation of Quantized Energy Transfer using Topological Photon Pump

Topological Floquet energy pumps, which use periodic driving to create a topologically protected quantized energy current, have been proposed and studied theoretically, but have never been observed directly. Previous works proposed that such a pump could be realized with a strongly driven superconducting qubit coupled to a cavity [1] and experimentally demonstrated that the proposed hierarchy of energy scales and drive frequencies can be realized in the circuit QED platform [2]. In this talk, we present experimental evidence of quantized energy transfer between a rotating synthetic magnetic field and a long-lifetime microwave CPW cavity via a transmon qubit. This demonstrates the experimental realization of Topological Floquet energy pumps and paves the way to preparing highly-excited non-classical cavity states in the future.

[1] D. M. Long et al., Phys. Rev. Lett. 128, 183602 (2022)

[2] M. Ritter et al., Phys. Rev. A 112, 042605 (2025)