Xiao-Cheng Lu

Coherent transfer via parametric control of normal-mode splitting in a superconducting multimode resonator

  1. Kai-I Chu,
  2. Xiao-Cheng Lu,
  3. Hsin Chang,
  4. Wei-Cheng Hung,
  5. Jing-Yang Chang,
  6. Jeng-Chung Chen,
  7. Chii-Dong Chen,
  8. and Yung-Fu Chen
Microwave storage and retrieval are essential capabilities for superconducting quantum circuits. Here, we demonstrate an on-chip multimode resonator in which strong parametric modulation
induces a large and tunable normal-mode splitting that enables microwave storage. When the spectral bandwidth of a short microwave pulse covers the two dressed-state absorption peaks, part of the pulse is absorbed and undergoes coherent energy exchange between the modes, producing a clear time-domain beating signal. By switching off the modulation before the beating arrives, we realize on-demand storage and retrieval, demonstrating an alternative approach to microwave photonic quantum memory. This parametric-normal-mode-splitting protocol offers a practical route toward a controllable quantum-memory mechanism in superconducting circuits.
arxiv pdf

Slow and Stored Light via Electromagnetically Induced Transparency Using A Λ-type Superconducting Artificial Atom

  1. Kai-I Chu,
  2. Xiao-Cheng Lu,
  3. Kuan-Hsun Chiang,
  4. Yen-Hsiang Lin,
  5. Chii-Dong Chen,
  6. Ite A. Yu,
  7. Wen-Te Liao,
  8. and Yung-Fu Chen
Recent progresses in Josephson-junction-based superconducting circuits have propelled quantum information processing forward. However, the lack of a metastable state in most superconducting
artificial atoms hinders the development of photonic quantum memory in this platform. Here, we use a single superconducting qubit-resonator system to realize a desired Λ-type artificial atom, and to demonstrate slow light with a group velocity of 3.6 km/s and the microwave storage with a memory time extending to several hundred nanoseconds via electromagnetically induced transparency. Our results highlight the potential of achieving microwave quantum memory, promising substantial advancements in quantum information processing within superconducting circuits.
arxiv pdf