RQC Seminar

237th RQC Seminar

• Speaker

  Dr. Chu Kai-I
  ( National Central University, Taiwan )

• Date

  15:00-16:00 (3:00 p.m.-4:00 p.m.), October 20, 2025 Monday

• Venue

  Hybrid(ZOOM・ Room S507 at Wako Chemistry and Materials Physics Building / 物質科学研究棟 S507 (S51))

• Title

  Highly Efficient Broadband Microwave Storage and Retrieval Using a Superconducting Chiral Λ-Type Molecule

• Inquiries

  yasunobu.nakamura[at]riken.jp

Abstract
Microwave quantum memory is a key component for large-scale superconducting-circuit-based quantum networks. In our previous study, we developed a Λ-type superconducting artificial atom using a single qubit-resonator system with parametric modulation to achieve slow light and microwave storage based on electromagnetically induced transparency. However, storage efficiency is limited by incomplete pulse compression within the single-atom medium and bidirectional emission. To overcome these limitations, we theoretically propose a high-efficiency microwave storage and retrieval approach using a superconducting artificial chiral molecule embedded in a one-dimensional open transmission line. Its Λ-type structure enables both electromagnetically-induced-transparency-based and Raman-based microwave memories. By developing an optimal control protocol for the parametric modulations applied to the molecule, we achieve full pulse compression and unidirectional emission, attaining nearly 100% storage efficiency and near-unity fidelity, provided that the adiabatic condition is satisfied. Unlike previous schemes based on a single giant unidirectional emitter, which restrict storage to essentially single-frequency operation due to phase-matching conditions, our control method broadens the storage bandwidth to tens to hundreds of megahertz, making it suitable for quantum networks. These findings provide a viable pathway toward realizing practical microwave quantum memories in superconducting circuits.