A semi-classical versus quantum description of the ground state of three-level atoms interacting with a one-mode electromagnetic field.

Autor:	Cordero, S., Casta nos, O., L'opez-Pena, R., Nahmad-Achar, E.
Předmět:	SEMI-classical model (Atomic physics) QUANTUM mechanics GROUND state (Quantum mechanics) ELECTROMAGNETIC fields QUANTUM phase transitions PHOTON counting
Zdroj:	Journal of Physics A: Mathematical & Theoretical; 12/20/2013, Vol. 46 Issue 50, p1-25, 25p
Abstrakt:	We consider Na three-level atoms (or systems) interacting with a one-mode electromagnetic field in the dipolar and rotating wave approximations. The order of the quantum phase transitions is determined explicitly for each of the configurations ..., Λ and V, with and without detuning. The semi-classical and exact quantum calculations for both the expectation values of the total number of excitations M =〈M〉 and photon number n = 〈n〉 have excellent correspondence as functions of the control parameters. We prove that the ground state of the collective regime obeys sub-Poissonian statistics for the M and n distribution functions. Therefore, their corresponding fluctuations are not well described by the semi-classical approximation. We show that this can be corrected by projecting the variational state to a definite value of M. [ABSTRACT FROM AUTHOR]
Databáze:	Complementary Index
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