Atomic squeezing in three level atoms

Feifan Liu, Mao-Fa Fang, Xiong Xu

The entropy squeezing for a three-level atom interacting with a single-model field is studied. A general definition of entropy squeezing for three-level atom is given according to entropic uncertainty relation of three-level system, and the calculation formalism of entropy is derived for a cascade three-level atom. By using numerical calculation, the entropy squeezing properties of a cascade three-level atom are examined. Our results show that, three-level atom can generate obvious entropy squeezing effect via choosing appropriate superposition state of three-level atom. Our results are meaningful for preparing three-level system information resources with ultra-low quantum noise.

Osvaldo Civitarese, M. Reboiro, Lorena Rebón +1 more

Wen-Jin Huang, Mao-Fa Fang

The entropy squeezing properties of different types of moving three-level atoms coupled with a single-mode coherent field are studied. The influences of the moving velocity and initial states of the three-level atom on the entropy squeezing are discussed. The results show that, the entropy squeezing properties of the three-level atom depend on its initial state, moving velocity, and the type. A stationary three-level atom can not obtain a steady entropy squeezing whatever initial conditions are chosen, while a moving three-level atom can achieve a steady and optimal entropy squeezing through choosing higher velocity and appropriate initial state. Our result provides a simple method for preparing squeezing resources with ultra-low quantum noise of the three-level atomic system without additional any complex techniques.

Ram Narayan Deb

Wang Qi-fang

The atomic dipole squeezing is a very important phenomenon in the interaction between an atom and an optical field, but the atomic dipole squeezing of a three-level atom with an intensity-dependent coupling is seldom reported. By using a full quantum theory, We investigate the time-evolution properties of the atomic dipole squeezing of the degenerate quantum-beat three-level atom intensity-dependently interacting with a single-mode coherent field, and explore effects of splitting of the lower energy levels of the atom, the field intensity and the initial atomic coherence on the atomic dipole squeezing. Our results show that, when the two lower levels of the atom is degenerate, dipole squeezing parameters evolve periodically with time, and the splitting of the lower levels destroy this periodicity and reduce the amount of dipole squeezing. The relationship between the amount of dipole squeezing and the initial coherent field intensity is not monotonous. The initial atomic coherence has a great influence on the dipole squeezing.

P. L. Knight, Stephen Mark Barnett, Bryan J. Dalton +3 more