Research activities on superconducting quantum devices in NICT
Hirotaka Terai - NICT (National Institute of Information and Communications Technology), Kobe, Japan.
Abstract:
Superconducting qubits are a promising quantum computing platform, but significant challenges remain, such as achieving sufficiently long and stable coherence times and precise control of circuit parameters. Further improvements in material processing are essential to overcome these challenges. In this presentation, we introduce our research activities on superconducting quantum circuit technology based on nitride superconductors and recent significant improvement of the coherence times up to 1 ms in the superconducting qubits based on NbN/AlN/NbN epitaxial junctions.
Ultrafast generation of entangled photon pair and its applications
Yoshiaki Tsujimoto - NICT (National Institute of Information and Communications Technology), Kobe, Japan.
Abstract:
Entangled photon pairs are a key resource for optical quantum information processing. In the widely used spontaneous parametric down-conversion (SPDC) process, increasing the pump power enhances the photon-pair generation probability, but simultaneously increases the probability of multiphoton-pair generation, leading to an inherent trade-off between the generation rate and the quality of entanglement. In our research group, we have overcome this limitation by employing high-speed pump pulse trains generated through second-harmonic generation of an electro-optic frequency comb, thereby achieving a high photon-pair generation rate while preserving the quality of entanglement. In this presentation, I will introduce the development of a GHz-rate entangled photon-pair source and present our latest experimental results obtained using this platform.
Location: QNC 1201