scholarly journals Evolution of the quantum fidelity in a system of multimode light field interacting resonantly with a two-level atom through degenerate multi-photon process

2014 ◽  
Vol 63 (18) ◽  
pp. 184203
Author(s):  
Wang Ju-Xia
Keyword(s):  
Light Field ◽  
Level Atom ◽  
Photon Process ◽  
Multimode Light ◽  
Quantum Fidelity

scholarly journals Hydrogen spin oscillations in a background of axions and the 21-cm brightness temperature

2020 ◽  
Author(s):  
G Lambiase ◽  
S Mohanty
Keyword(s):  
Cosmic Strings ◽  
Transition Rates ◽  
Spin Temperature ◽  
Level Atom ◽  
Spin Flip ◽  
Coherent Field ◽  
Unique Method ◽  
Photon Process ◽  
The Right ◽  
The Universe

Abstract The 21-cm line signal arising from the hyperfine interaction in hydrogen has an important role in cosmology and provides a unique method for probing of the universe prior to the star formation era. We propose that the spin flip of Hydrogen by the coherent emission/absorption of axions causes a lowering of their spin temperature and can explain the stronger than expected absorption of 21-cm light reported by the EDGES collaboration. We find the analogy of axion interaction with the two level HI with the Jaynes-Cummings model of a two level atom in a cavity and we derive the spin flip frequency in this formalism and show that the coherent oscillations frequency Ω∝1/fa in contrast with the incoherent transitions between the HI hyperfine levels where the transition rates $\propto 1/f_a^2$. The axion emission and absorption rates are equal but the spin temperature is still lowered due to different selection rules for the spin flip transitions compared to the photon process. We show that the axion process goes in the right direction for explaining the EDGES observation. For this mechanism to work we require a coherent field of relativistic axions with energy Eν peaked at the 21-cm spin-flip energy. Such a coherent background of relativistic axions can arise from the decay of cosmic strings if the decay takes place in the electroweak era.

scholarly journals Non-Gaussian quantum states of a multimode light field

2019 ◽  
Vol 16 (2) ◽  
pp. 144-147 ◽  
Author(s):  
Young-Sik Ra ◽  
Adrien Dufour ◽  
Mattia Walschaers ◽  
Clément Jacquard ◽  
Thibault Michel ◽  
...  
Keyword(s):  
Light Field ◽  
Quantum States ◽  
Multimode Light ◽  
Non Gaussian

CONTROL OF COLLAPSE-REVIVAL PHENOMENON USING A TIME VARYING SQUEEZED FIELD

2011 ◽  
Vol 20 (02) ◽  
pp. 155-165 ◽  
Author(s):  
K. V. PRIYESH ◽  
RAMESH BABU THAYYULLATHIL
Keyword(s):  
Time Evolution ◽  
Frequency Modulation ◽  
Population Inversion ◽  
Light Field ◽  
Time Varying ◽  
Light Atom ◽  
Squeezed Light ◽  
Level Atom ◽  
Time Varying Frequency ◽  
Atom Interaction

We have investigated the interaction of two level atom with time varying quadrature squeezed light field. Jaynes-Cummings model is used for solving the atom radiation interaction. Time evolution of the system for different squeezing parameter and phase have been studied. There are no well-defined revivals in population inversion when the squeezed phase is π and the squeezing parameter is greater than 0.5. Using a time varying frequency for the light field, it is found that the randomness of the population inversion and the collapse revival phenomena can be controlled. Frequency modulation of the field can thus be used as a tool for manipulating the squeezed light atom interaction.

The exact solution of a two-level atom moving in a quantized travelling light field and a gravitational field

2001 ◽  
Vol 10 (10) ◽  
pp. 935-940
Author(s):  
Zou Xu-bo ◽  
Xu Jing-bo ◽  
Gao Xiao-chun ◽  
Fu Jian
Keyword(s):  
Exact Solution ◽  
Gravitational Field ◽  
Light Field ◽  
Level Atom

An Improved Laser Model based on the Nonlinear Coupling of Lightfield with Boson Elementary Excitation

1998 ◽  
Vol 07 (04) ◽  
pp. 479-486 ◽  
Author(s):  
He Minggao ◽  
Ou Fa
Keyword(s):  
Light Field ◽  
Elementary Excitation ◽  
Nonlinear Coupling ◽  
Threshold Behavior ◽  
Laser Threshold ◽  
Model Based ◽  
Pumping System ◽  
Self Organized ◽  
Level Atom ◽  
Laser Model

The dynamics of the laser model based on the nonlinear coupling of light-field with boson elementary excitation is improved. A rate equation of pumping system directly coupled with the boson matter is added to the original equations. The system as a whole, therefore, becomes a perfect self-organized one, but the character of mirrorless unchanges, which is a character essentially different from conventional lasers, and the laser threshold behavior of second-order-like transition also remains. There is some resemblance between the new revised laser model and Maxwell–Bloch two-level-atom laser model.

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