Phonon superradiance with time delays from collective giant atoms

The giant atom regime where the wavelength of the phonon field is smaller than the atomic size opens up new opportunities for exploring exotic phenomena and developing powerful quantum technologies. Here, we explore the radiation dynamics of a hybrid system consisting of a superconducting giant atomic ensemble and an acoustic waveguide. In particular, we show how to design the delayed feedback of the slow acoustic field on the giant atomic ensemble. This modulates the phonon superradiant dynamics into engineerable revival modes and unconventional scaling laws with respect to the number of giant atoms. These are a distinctive feature of time-delayed collective processes that have no analog in other settings. The recipes we provide for harnessing collective giant atoms can be exported to other platforms, laying the foundation for a variety of quantum simulations and applications.