A concise review of Rydberg atom based quantum computation and quantum simulation

Quantum information processing based on Rydberg atoms emerged as a promising direction two decades ago.Recent experimental and theoretical progresses have shined exciting light on this avenue.In this concise review,we will briefly introduce the basics of Rydberg atoms and their recent applications in associated areas of neutral atom quantum computation and simulation.We shall also include related discussions on quantum optics with Rydberg atomic ensembles,which are increasingly used to explore quantum computation and quantum simulation with photons.

Subnatural-linewidth fluorescent single photons

Subnatural-linewidth single photons are of vital importance in quantum optics and quantum information science.According to previous research, it appears difficult to utilize resonance fluorescence to generate single photons with subnatural linewidth. Here we propose a universally applicable approach to generate fluorescent single photons with subnatural linewidth, which can be implemented based on Λ-shape and similar energy structures.Further, the general condition to obtain fluorescent single photons with subnatural linewidth is revealed.The single-photon linewidth can be easily manipulated over a broad range by external fields, which can be several orders of magnitude smaller than the natural linewidth. Our study can be easily implemented in various physical platforms with current experimental techniques and will significantly facilitate the research on the quantum nature of resonance fluorescence and the technologies in quantum information science.

Observation of topological rainbow in non-Hermitian systems

Topological photonic states have promising applications in slow light,photon sorting,and optical buffering.However,realizing such states in non-Hermitian systems has been challenging due to their complexity and elusive properties.In this work,we have experimentally realized a topological rainbow in non-Hermitian photonic crystals by controlling loss in the microwave frequency range for what we believe is the first time.We reveal that the lossy photonic crystal provides a reliable platform for the study of non-Hermitian photonics,and loss is also taken as a degree of freedom to modulate topological states,both theoretically and experimentally.This work opens a way for the construction of a nonHermitian photonic crystal platform,will greatly promote the development of topological photonic devices,and will lay a foundation for the real-world applications.

纤维蛋白原类淀粉样聚集膜的制备及其性能研究

利用血液中含量丰富的糖蛋白—纤维蛋白原,通过纤维蛋白原与还原剂三(2-羧乙基)磷盐酸盐(TCEP)反应,制备了基于纤维蛋白原类淀粉样聚集的纳米薄膜.利用荧光光谱、远紫外-圆二色谱等光学表征手段,探究了纤维蛋白原与TCEP反应的动力学过程及其二级结构的变化;通过透射电子显微镜对薄膜结构进行了表征;用原子力显微镜和光学椭偏仪探讨了反应时间、纤维蛋白原浓度、TCEP溶液pH值以及浓度对薄膜厚度的影响,通过原子力显微镜表征了其在不同溶剂中浸泡的稳定性;最后通过薄膜的血小板吸附实验和对蛋白质的吸附实验,表征了其抗污能力.实验结果表明:通过反应条件的控制,实现了对薄膜厚度的可控,且薄膜在不同的环境中表现出优异的稳定性;薄膜表现出了对血小板、蛋白质、生物体液(如胎牛血清、牛奶等)等非特异性吸附的良好抵抗能力,有望作为新一代生物基抗污材料运用于表/界面改性领域.

Optimal phase sensitivity of atomic Ramsey interferometers with coherent spin states

We present a detailed analysis of phase sensitivity for a nonlinear Ramsey interferometer, which utilize effective mean-field interaction of a two-component Bose-Einstein condensate in phase ac- cumulation. For large enough particle number N and small phase shift φ, analytical results of the Ramsey signal and the phase sensitivity are derived for a product coherent state θ, 0）. When collisional dephasing is absent, we confirm that the optimal sensitivity scales as 2/N3/2 for polar angle of the initial state θ = π/4 or 3π/4. The best-sensitivity phase satisfies different transcendental equations, depending upon the initial state and the observable being measured after the phase accumulation. In the presence of the collisional dephasing, we show that the N-3/2-scaling rule of the sensitivity maintains with spin operators jx and jy measurements. A slightly better sensitivity is attainable for optimal coherent state with θ = π/6 or 5π/6.

Loss-induced nonreciprocity

Nonreciprocity is important in both optical information processing and topological photonics studies.Conventional principles for realizing non reciprocity rely on magnetic fields,spatiotemporal modulation,or nonlinearity.Here we propose a generic principle for generating nonreciprocity by taking advantage of energy loss,which is usually regarded as harmful.The loss in a resonance mode induces a phase lag,which is independent of the energy transmission direction.When multichannel lossy resonance modes are combined,the resulting interference gives rise to nonreciprocity,with different coupling strengths for the forward and backward directions,and unidirectional energy transmission.This study opens a new avenue for the design of nonreciprocal devices without stringent requirements.

On-chip topological nanophotonic devices

On-chip topological nanophotonic devices,which take photons as in-formation carriers with topological protection during light propaga-tion,have great application potential in the next generation photonic chips.The topological photonic states enable the nanophotonic de-vices to be robust and stable,immune to scattering even with imper-fect structures.The development,opportunities and challenges of the on-chip topological nanophotonic devices have attracted great atten-tion of scholars,and desired to be known.In this review,topologi-cal devices were introduced in the order of functionalities on an in-tegrated photonic chip,i.e.topological light source,topological light waveguiding,topological light division and selection,topological light manipulation and topological light detecting.Finally,we gave out-looks for predicting and promoting the performances of on-chip topo-logical nanophotonic devices from the angles of non-Hermitian sys-tems,non-Abelian topology,metasurfaces,intelligent algorithms and multiple functional topological nanophotonic integration.This review provides rich knowledge about on-chip topological nanophotonic de-vices.The insights in this paper will spark inspiration and inspire new thinking for the realization of topological photonic chips.