The two-photon approximation for the four-photon decay of the 4d excited state in hydrogenThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

2011 ◽  
Vol 89 (1) ◽  
pp. 123-127 ◽  
Author(s):  
D. Solovyev ◽  
L. Labzowsky
Keyword(s):  
Excited State ◽  
Hydrogen Atom ◽  
Early Universe ◽  
Recombination Process ◽  
Atomic Systems ◽  
International Conference ◽  
Two Photon ◽  
Photon Decay ◽  
Hydrogen Recombination ◽  
History Of

The method of two-photon approximation for multiphoton decay is applied to the decay of the 4d state in the hydrogen atom. In the process of four-photon decay the two-photon contribution that leads to radiation escape, from the interaction with matter, is considered. This may be helpful for a strict description of the recombination process in the hydrogen atom and, in principle, for the history of hydrogen recombination in the early universe.

4s-1s two-photon decay in hydrogen atom with allowance for cascades

2011 ◽  
Vol 110 (3) ◽  
pp. 328-334 ◽  
Author(s):  
T. A. Zalyalyutdinov ◽  
D. A. Solovyev ◽  
L. N. Labzovskii
Keyword(s):  
Hydrogen Atom ◽  
Two Photon ◽  
Photon Decay

Femtosecond Spectroscopic Studies of the One- and Two-Photon Excited-State Dynamics of 2,2,17,17-Tetramethyloctadeca-5,9,13-trien-3,7,11,15-tetrayne:  A Trimeric Oligodiacetylene

2006 ◽  
Vol 110 (40) ◽  
pp. 11435-11439 ◽  
Author(s):  
Grzegorz M. Balkowski ◽  
Michiel Groeneveld ◽  
Hong Zhang ◽  
Cindy C. J. Hendrikx ◽  
Michael Polhuis ◽  
...  
Keyword(s):  
Excited State ◽  
Spectroscopic Studies ◽  
Excited State Dynamics ◽  
Two Photon ◽  
The One

scholarly journals Displaced new physics at colliders and the early universe before its first second

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lorenzo Calibbi ◽  
Francesco D’Eramo ◽  
Sam Junius ◽  
Laura Lopez-Honorez ◽  
Alberto Mariotti
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Upper Bound ◽  
New Physics ◽  
Early History ◽  
Relic Density ◽  
History Of ◽  
Indirect Information ◽  
The Universe

Abstract Displaced vertices at colliders, arising from the production and decay of long-lived particles, probe dark matter candidates produced via freeze-in. If one assumes a standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density constraint. Here, we argue how displaced events could very well point to freeze-in within a non-standard early universe history. Focusing on the cosmology of inflationary reheating, we explore the interplay between the reheating temperature and collider signatures for minimal freeze-in scenarios. Observing displaced events at the LHC would allow to set an upper bound on the reheating temperature and, in general, to gather indirect information on the early history of the universe.

scholarly journals Dynamical Symmetries of the H Atom, One of the Most Important Tools of Modern Physics: SO(4) to SO(4,2), Background, Theory, and Use in Calculating Radiative Shifts

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1323 ◽  
Author(s):  
G. Jordan Maclay
Keyword(s):  
Hydrogen Atom ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Bound States ◽  
Integrated Treatment ◽  
Invariance Group ◽  
Elementary Particle Physics ◽  
Background Theory ◽  
Modern Physics ◽  
History Of

Understanding the hydrogen atom has been at the heart of modern physics. Exploring the symmetry of the most fundamental two body system has led to advances in atomic physics, quantum mechanics, quantum electrodynamics, and elementary particle physics. In this pedagogic review, we present an integrated treatment of the symmetries of the Schrodinger hydrogen atom, including the classical atom, the SO(4) degeneracy group, the non-invariance group or spectrum generating group SO(4,1), and the expanded group SO(4,2). After giving a brief history of these discoveries, most of which took place from 1935–1975, we focus on the physics of the hydrogen atom, providing a background discussion of the symmetries, providing explicit expressions for all of the manifestly Hermitian generators in terms of position and momenta operators in a Cartesian space, explaining the action of the generators on the basis states, and giving a unified treatment of the bound and continuum states in terms of eigenfunctions that have the same quantum numbers as the ordinary bound states. We present some new results from SO(4,2) group theory that are useful in a practical application, the computation of the first order Lamb shift in the hydrogen atom. By using SO(4,2) methods, we are able to obtain a generating function for the radiative shift for all levels. Students, non-experts, and the new generation of scientists may find the clearer, integrated presentation of the symmetries of the hydrogen atom helpful and illuminating. Experts will find new perspectives, even some surprises.

Two-photon decay in gold atoms following photoionization with synchrotron radiation

2003 ◽  
Vol 67 (5) ◽  
Author(s):  
R. W. Dunford ◽  
E. P. Kanter ◽  
B. Krässig ◽  
S. H. Southworth ◽  
L. Young ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Two Photon ◽  
Photon Decay
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