約瑟夫森介面型人造原子和超導共振腔光場共同形成的電路量子電動力學架構，非常適合研究原子與光之間強耦合的量子光學，此架構的設計彈性與可擴展性，用以發展量子信息處理的各個應用領域也非常理想，尤其是量子計算，而量子記憶體是許多量子演算法所需的基本組件。電磁誘發透明性質（EIT）享有慢光現象及光捕捉能力，能夠使用存儲光子攜帶的信息。此計畫主旨是關於在超導電路系統中開發基於EIT性質的量子記憶體。發展EIT型超導量子記憶體的主要障礙，來自於超導人工原子中，通常不存在Λ型偶極躍遷能級結構。此計畫中，我們提出在超導電路實現Λ型EIT的可行方案。我們計劃使用交流磁場快速調制transmon型人造原子的躍遷頻率，此策略可開闢新的躍遷通道，將transmon系統轉變為具有Λ型能級結構的人工原子，成為合適EIT現象發生的平台。至於實現Λ型EIT方案中所需的亞穩態，可以使用耦合transmon系統的亞輻射狀態，或通過設計製作於晶片上的帶阻濾波器，抑制特定頻率下的自發輻射來實現。Λ型EIT的進展，將為超導電路量子記憶體存儲技術的發展做好準備。 ;Josephson-junction-based artificial atoms and superconducting cavities together form circuit quantum electrodynamics architecture, which is perfect for studying quantum optics of strong coupling between atom and light. This architecture is even ideal for developments in various application aspects of quantum information processing, especially quantum computing. Quantum memory is a fundamental component required for many quantum computing algorithms. Electromagnetically induced transparency (EIT) enjoys the slow light and the trapped light phenomena, and is therefore capable of storing information carried by photons. This proposal is regarding developing EIT-based quantum memory in superconducting circuit systems. The main obstacle for EIT superconducting memory comes from that superconducting artificial atoms typically do not favor Λ-type dipole-allowed transition level structure. In this proposal, we suggest new feasible Λ-type schemes for realizing EIT in superconducting circuits. We plan to utilize the fact that transition frequency of transmon atom can be quickly modulated by an AC magnetic field. This strategy can open a new transition channel, transform transmon systems into artificial atoms with Λ-type energy level structure, and create suitable EIT platforms. The required metastable excited state in Λ-type scheme can be achieved by using the subradiance state of a coupled transmon system, or by using design of on-chip band-stop filter to suppress radiation decay at specific frequencies. The advance of Λ-type EIT scheme in superconducting circuits will pave a way for the developments of quantum memory technology.
