Study on analysis and control of optical systems for high-performance quantum optical measurement and computing

Yan Xu, Xinran Su, Zhen Chai +1 more

Abstract Metasurface‐based optical field manipulation has significantly broadened the application range of micro‐optical components and integrated optics, gradually replacing bulky and complicated optical components. With the continuous development of micro and nano processing technology as well as computational analysis technology, metasurfaces have progressively shown their superior application prospects. After demonstrating tremendous results in classical optical applications, their application range has now extended to the field of quantum sensing. Due to their unique properties, such as small planar size, easy integration, flexible performance design, and tunable functionality, they have opened up a series of novel and rich applications for generating, manipulating, controlling, and detecting optical fields. In this paper, the basic principle and implementation of quantum measurement are presented and an overview of the design principles of metasurfaces, along with a summary of the latest advancements and potential applications of these surfaces in optical field modulation techniques for quantum precision measurement. Additionally, a thorough discussion and analysis of the challenges encountered by metasurfaces and their future development prospects is provided. Metasurfaces offer brand‐new opportunities for low‐cost, high‐performance, multifunctional miniaturized quantum sensors and are expected to play a significant role in the development of next‐generation quantum sensors.

Daniel Pérez Calero, Robert S. Wezeman, Stefan Baümer

J. I. Cirac, Thomas Pellizzari, J. F. Poyatos +1 more

S Vijayaram, Pagavathigounder Balasubramaniam

In this paper, authors present a physics-informed neural networks (PINN) approach for solving the optimal control problem (OCP) of the stochastic Schrödinger equation (SSE), with an emphasis on applications in quantum optics. The SSE models quantum systems under uncertainty, a scenario often encountered in open quantum systems where environmental interactions introduce randomness into the system dynamics. These stochastic dynamics are particularly relevant in quantum optics, where precise control over quantum states is crucial for applications such as quantum computing, secure communication, and measurement protocols. Traditional numerical methods for solving such problems face limitations due to high computational costs and the complexity associated with stochastic partial differential equations. The proposed approach utilises PINN, a type of deep learning model that integrates physical laws directly into the learning process by incorporating loss functions based on governing equations, initial and boundary conditions. The fidelity-based objective function is constructed to achieve the desired quantum state so as to develop an OCP solving algorithm. The proposed work is distinguished between deterministic drift-based training and post-training stochastic validation. Extensive numerical experiments are demonstrated near-unity deterministic fidelity. Further, a systematic architecture study validated that a moderately deep network yielded optimal performance with reduced computational cost. Fidelity dissipation analysis confirmed that the method maintained accuracy even under strong damping. These findings established the PINN as an efficient and physically consistent framework for quantum optimal control in open systems.

Shigeki Takeuchi

Randall D. Knight

A laser-induced fluorescence technique combined with the observation of spontane ous magnetic dipole photons from the highly metastable 2 3 S t state of Li + has been used to measure the radiative lifetime of this state.The ions are created by electron impact on a lithium A. Direct Determination of the Spontaneous Decay Curve .... 18 B. Direct Determination of the Number of Remaining Metastables 20 C. Indirect Determination of the Radiative Lifetime 23 IV.Ion Trap Theory and Performance 29 A. The RF-Quadrupole Ion Trap 29 B. The Ion Detection System 36 C. Ion Trap Performance 43 1.Ion storage 43 2. Ion distribution 50 V.Experimental Methods 56 A. The Vacuum System 56 B. The Lithium Oven and Hot Wire Detector 60 C. The Ion Trap and Electron Gun 62 D. The Magnetic Field 66 1. Detector operation ..... 73 2. Detector calibration 76 6.The Laser and Optical System 81 H.The Computer System 84 1. Timing and control .84 2. Operating and analysis programs 88 VI.Experimental Results 93 A. The Detection of Spontaneous Ml Photons 93 B. The Detection of Laser-Induced Photons 96 C. The Metastable Lifetime and Nonradiative Quenching .... 99 D. Procedures in Measuring the Radiative Lifetime 104 E. Data Reduction and Error Analysis Ill VII.Conclusion 119 Appendix A. Optical Pumping Calculations .121 A. The Magic Angle 121 B. The Optical Pumping Equations 123 C. Results of the Calculations .126 Appendix B. Measurements of the Ion Density Distribution 128 A. The Laser Scanning Technique 128 B. Experimental Results 130 Acknowledgements ....