工作坊 | 2023年04月15日
為讓高中生發掘更多科學的奧秘，科大理學院將於 2023年 4月至5月期間舉辦新一系列七場科學實驗工作坊。參加者將親臨科大校園裡探索科學。 工作坊旨在讓你體驗大學的科學學習，你將通過一些有趣的科學實驗示範及各種教學活動去尋找學習科學的樂趣，並探索自己的意向和興趣。 請到https://bit.ly/3VW3Zxy 查看詳情及報名。 申請截止日期為 2023年2月28日(23:59)。 現在就來報名參加吧！
研討會, 演講, 講座 | 2023年03月14日
IAS Center for Quantum Technologies Seminar Series - New Platforms for Quantum Sensing and Quantum Computing
Abstract The nitrogen vacancy (NV) center in diamond exhibits spin-dependent fluorescence and long spin coherence times under ambient conditions, enabling applications in quantum information processing and sensing. NV centers near the surface can have strong interactions with external materials and spins, enabling new forms of nanoscale spectroscopy. However, NV spin coherence degrades within 100 nanometers of the surface, suggesting that diamond surfaces are plagued with ubiquitous defects. The speaker will describe her research group’s recent efforts to correlate direct materials characterization with single spin measurements to devise methods to stabilize highly coherent NV centers within nanometers of the surface. They deploy these coherent shallow NV centers for a new nanoscale sensing technique, whereby they use covariance measurements of two or more NV centers to measure two-point magnetic field correlators. The speaker will also discuss steps towards controlling diamond surface chemistry to develop NV centers as a platform for nanoscale NMR. The speaker’s approach for correlating surface spectroscopy techniques with single qubit measurements to realize directed improvements is generally applicable to many systems. Separately, the speaker will describe their recent efforts to tackle noise and microwave losses in superconducting qubits. Building large, useful quantum systems based on transmon qubits will require significant improvements in qubit relaxation and coherence times, which are orders of magnitude shorter than limits imposed by bulk properties of the constituent materials. This indicates that loss likely originates from uncontrolled surfaces, interfaces, and contaminants. Previous efforts to improve qubit lifetimes have focused primarily on designs that minimize contributions from surfaces. However, significant improvements in the lifetime of planar transmon qubits have remained elusive for several years. The speaker’s research group has recently fabricated planar transmon qubits that have both lifetimes and coherence times exceeding 0.3 milliseconds by replacing niobium with tantalum in the device. Following this discovery, they have parametrized the remaining sources of loss in state-of-the-art devices using systematic measurements of the dependence of loss on temperature, power, and geometry. This parametrization, complemented by direct materials characterization, allows for rational, directed improvement of superconducting qubits. About the Speaker Prof. Nathalie DE LEON received her BS in Chemistry from Stanford University in 2004 and her PhD in Chemical Physics from Harvard University in 2011. She then worked as a Center for Integrated Quantum Materials and Element Six Postdoctoral Fellow at Harvard. In 2016, she joined the faculty of Princeton University as an Assistant Professor in the Department of Electrical and Computer Engineering and is currently an Associate Professor there. Prof. De Leon’s research is focused on building quantum technologies with solid state defects and new material systems for superconducting qubits. She is currently the Materials Thrust Leader of the Co-design Center for Quantum Advantage, a National Quantum Information Science Center under the US Department of Energy. Prof. De Leon is the recipient of 2016 US Air Force Office of Scientific Research Young Investigator Award and 2017 Sloan Research Fellowship. In 2018, she received the US National Science Foundation’s Faculty Early Career Development Program Award, the US Defense Advanced Research Projects Agency’s Young Faculty Award, and the US Department of Energy’s Early Career Award. In 2023, she was awarded the Rolf Landauer and Charles H. Bennett Award in Quantum Computing by the American Physical Society for her substantial contributions to the field of experimental quantum information science. For Attendees' AttentionThis talk will be held online via Zoom. To attend, please join the Zoom meeting at https://hkust.zoom.us/j/92503111371 (Meeting ID: 925 0311 1371 / Passcode: 475970). About the Center For more information, please refer to the center website at https://iascqt.hkust.edu.hk/.
研討會, 演講, 講座 | 2023年02月24日
IAS Center for Quantum Technologies Seminar Series - Quantum Sensing of Quantum Materials
Abstract Exploring new class of quantum materials with advanced magnetic and electronic properties has been a central focus of modern condensed matter physics over the past decades. The success of these efforts relies simultaneously on advances in theory, material synthesis, and development of new, sensitive metrology tools capable of diagnosing the key material properties at the nanoscale. Nitrogen-vacancy (NV) centers, optically active atomic spin defects in diamond, are naturally relevant in this context due to their excellent quantum coherence, unprecedented spatial and field sensitivity, and remarkable functionality over broad experimental conditions. Serving as a local probe of multiple degrees of freedom, NV centers are ideally posed to investigate the fundamental correlations between microscopic spin, charge, and thermal behaviors in condensed matter systems. In this talk, the speaker will present her research group’s recent work on using NV centers to perform quantum sensing of emergent quantum materials. Specifically, they have utilized NV centers to visualize the exotic spin properties of topological magnetic materials and antiferromagnetic insulators, revealing the fundamental spin transport and dynamic physics at the nanoscale. Taking advantage of coherent coupling between NV centers and nanomagnetic devices, they achieved electric field induced coherent control of NV centers, promoting the role of NV centers at the forefront research of quantum science and technologies. Lastly, the speaker will briefly discuss their ongoing efforts on exploring 2D quantum sensing technologies using emergent color centers beyond NVs. About the Speaker Prof. DU Chunhui received her BS in Physics from East China Normal University in 2010 and her PhD in Physics from The Ohio State University in 2015. Before joining the University of California, San Diego (UCSD) in 2019, she was a Postdoctoral Fellow at Harvard University. She is currently an Assistant Professor of Physics at UCSD. Prof. Du’s current research focuses on developing color center-based quantum sensing technologies for studying emergent condensed matter systems. She is the recipient of the US National Science Foundation Career Award (2021), US Air Force’s Young Investigator Research Program Award (2021), US Department of Energy’s Early Career Award (2022), the International Union of Pure and Applied Physics Early Career Scientist Prize (2022) and the US Office of Naval Research’s Young Investigator Award (2023). For Attendees' AttentionThis talk will be held online via Zoom. To attend, please join the Zoom meeting at https://hkust.zoom.us/j/92503111371 (Meeting ID: 925 0311 1371 / Passcode: 475970). About the Center For more information, please refer to the center website at https://iascqt.hkust.edu.hk/.