Floquet Mode Josephson Traveling Wave Parametric Amplifier*

• Floquet Mode Traveling Wave Parametric Amplifiers (Floquet TWPAs) [1] are a recently proposed new amplifier paradigm that encodes information in the instantaneous collective Floquet modes which are transformed to single frequency modes at the interfaces. Floquet TWPAs have been theoretically predicted to overcome the bandwidth-quantum efficiency trade-off of the current state-of-the-arts and are in principle broadband, quantum-limited, and crucially directional at the same time. Consequently, Floquet TWPAs can be potentially integrated with qubits without isolators, enabling ideal broadband quantum measurements and opening up new possibilities for various information-critical applications in quantum information processing, metrology, and astronomy. Here, we discuss the practical advantages and challenges in realizing Floquet TWPAs on the superconducting quantum circuit platform and report our experimental results of Floquet Josephson TWPAs using an existing qubit-compatible fabrication process.
  
  [1] K. Peng, M. Naghiloo, J. Wang, G. D. Cunningham, Y. Ye, and K. P. O’Brien, “Near-ideal quantum efficiency with a Floquet mode traveling wave parametric amplifier”, arXiv:2104.08269 (2021).