报告题目2: Quantum Imaging and Three Surprising Stern–Gerlach Experiments
报告摘要: Entangled photons possess nonclassical correlations that can be harnessed for imaging. In contrast to conventional optical imaging, quantum imaging based on coincidence detection of entangled photons demonstrated super-resolution beyond the classical diffraction limit. We will present both experimental imaging results and the underlying theoretical framework that explains these advantages. Because photons originate from atoms and molecules, our work also examines atomic physics at the interface between classical and quantum formalisms. We show that the Bloch equation, traditionally regarded as a classical equation of motion, can be reformulated to yield the quantum von Neumann and Schrödinger equations. This correspondence reveals a classical origin for the standard quantum spin equations and clarifies the relationship between the two descriptions. Three unexpected experimental observations are presented. First, we model the multistage Stern–Gerlach experiment envisioned by Heisenberg and Einstein and conducted by Frische and Segre, with improved accuracy compared to existing treatments. More recently, we performed quantum measurements of atomic beam splitting under extremely low magnetic field gradients. Conventional Stern–Gerlach experiments rely on strong gradients to spatially resolve the split beams. In contrast, we use optical spectroscopy to resolve spatially overlapping atomic distributions that would otherwise appear inseparable, thereby enabling low-field quantum measurements. While conventional theoretical models agree with experiments at high magnetic fields, they exhibit noticeable discrepancies as the magnetic field gradient approaches zero. Our theory remains consistent with experimental observations across the entire field range. A key outcome of this work is an estimate of the electron spin collapse time, expressed in dimensionless units of Larmor precession cycles. Finally, inserting a null (zero magnetic field gradient) Stern–Gerlach stage before a standard stage yielded surprising effects as well.
报告专家简介： Lihong Wang is Bren Professor of Medical and Electrical Engineering at California Institute of Technology. His book entitled “Biomedical Optics” won the Goodman Book Writing Award. He has published 630 peer-reviewed journal articles and delivered 650 keynote/plenary/invited talks. His Google Scholar h-index and citations have reached 171 and 126K, and he is #1 most cited scientist in optics and #4 in nuclear medicine and medical imaging according to Stanford/Elsevier. His laboratory was the first to report functional photoacoustic tomography, 3D photoacoustic microscopy, and CUP (world’s fastest camera). He received the NIH Director’s Pioneer, NIH Director’s Transformative Research, and NIH/NCI Outstanding Investigator awards. He also received the Optica Mees Medal, Optica Feld Award, IEEE Technical Achievement Award, IEEE Biomedical Engineering Award, SPIE Chance Award, and IPPA Senior Prize. He is a Fellow of AAAS, AIMBE, Electromagnetics Academy, IAMBE, IEEE, NAI, Optica, and SPIE. An honorary doctorate was conferred on him by Lund University, Sweden. He was inducted into both National Academies of Engineering and Medicine.
主持人：肖云峰 教授
联系人：那 帅 助理教授 13911152288
科学前沿报告会(693)
