0000000001063210
AUTHOR
G. Benivegna
New Quantum Effects in the Dynamics of a Two-mode Field Coupled to a Two-level Atom
Abstract The dynamics of a degenerate two-mode electromagnetic field coupled to a single two-level atom is investigated both analytically and numerically. New quantum effects are discussed concerning the time dependence of the photon number and of its fluctuations, assuming that at t = 0 one of the modes is coherent and the other is empty. The field dynamics are dominated by oscillatory net exchanges of a large number of photons between the two modes, displaying amplitude decay. Over a longer time scale, revivals and collapses in the field populations take place. The time scales of these phenomena are much larger than those of the atomic Rabi oscillations decay. Moreover, the system attains…
Intraenvironmental correlations in the ground state of a nonisolated two-state particle
The existence of entanglement in the ground state of a two-level particle coupled to a bosonic environment is proved. The quantum covariances of pairs of simple dynamical variables relative to different subsystems are explicitly shown to be bounded. Physically interpretable conditions for the occurrence of weak intraenvironmental correlations are reported and discussed. The potentialities of our treatment are briefly put into evidence.
Collective behavior ofMbosonic modes interacting with a single two-level atom
The Hamiltonian describing, without the rotating-wave approximation (RWA), the linear interaction between M bosonic modes with an Einstein spectrum and a single two-level atom is exactly and canonically transformed introducing M suitable collective independent field modes, in such a way that only one among them is coupled to the atom. Some physical consequences of this fact are analyzed and, in particular, the existence of radiation-trapping phenomena together with the possibility of atomic absorption suppression is established. The applicability of the RWA to this system is discussed and the importance of the effective-field statistics for the time evolution of the system is pointed out.