Challenging QED with Hydrogen
Final Report Abstract
I have developed a technique for creating simulation codes of various spectroscopy experiments in multi-level atomic systems. The approach “programs write programs” uses a formalism of Master Equation (ME). The method is based on the processing of formalized atomic model in a numerical algebra code, which derives ME, apply analytic simplification, transform ME into realnumber form, and export fast C++ code for numerical integration of derived equations. I used this approach for several experiments on spectroscopy of Hydrogen and Deuterium aimed for high-precision tests of QED. The most important result of this work is concerned with the 1S-3S experiment in atomic hydrogen in Garching. Fast simulation code and many simulations help us find a way to overcome the most critical systematic effects in the experiment. Our measurement became the second-best measurement in hydrogen and provided a new important data point for solving the Proton Size Puzzle. One of the project’s objectives was to develop a simulation code of a family of 2S-nP experiments in Hydrogen and Deuterium. I mainly completed this work. The simulation for Hydrogen transitions has shown that the measurement with n=8 has a problem with systematic effects, and it is better not to spend laboratory efforts for that. The experiments with n=6, 9 and 10 in hydrogen are possible and have good perspectives. The simulation also shows potential problems for the correspondent Deuterium experiment, setting limits on laser polarization purity, asymmetry of initial state preparation and magnetic field. The developed approach was also helpful for calculating the collisional shift of different transitions in atomic hydrogen. The most ambitious objective of the project was the development of a universal code capable of generating a simulation code for an arbitrary atomic system. I mainly completed this work in the form of MEDWED code. However, making developed code easy to use and user-friendly become an unsolved problem, which did not allow me to publish this result. To summarize, I developed an approach for the simulation of various spectroscopy experiments in hydrogen to improve current QED tests by decreasing the uncertainty of the measurements. The results for the 1S-3S experiment were published in "Science". The development of universal code for the arbitrary atomic system was not finished primarily because of the unsolved problem of making the code user-friendly.
Publications
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Pressure shifts in high-precision hydrogen spectroscopy. I. Long-range atom-atom and atom-molecule interactions. Journal of Physics B 52, 075005 (2019)
U. D. Jentschura, C. M. Adhikari, R. Dawes, A. Matveev, N. Kolachevsky
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Pressure shifts in highprecision hydrogen spectroscopy: II. Impact approximation and Monte-Carlo simulations. Journal of Physics B 52, 075006 (2019)
A. Matveev, N. Kolachevsky, C. M. Adhikari, U. D. Jentschura
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Quantum Interference Line Shifts of Broad Dipole- Allowed Transitions. Annalen der Physik 531, 1900044 (2019)
T. Udem, L. Maisenbacher, A. Matveev, V. Andreev, A. Grinin, A. Beyer, N. Kolachevsky, R. Pohl, D. C. Yost, T. W. Hänsch.
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Two-photon frequency comb spectroscopy of atomic hydrogen. Science 370, 1061 (2020)
A. Grinin, A. Matveev, D. C. Yost, L. Maisenbacher, V. Wirthl, R. Pohl, T. W. Hänsch, T. Udem
