Entropy squeezing for a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel with weak measurement

The entropy squeezing of a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel is investigated in detail. Our results show that when coupled to the single-mode field, the atom in appropriate initial states can not only generate obvious entropy squeezing but also keep in the optimal squeezing state,while passing through the amplitude damping channel, the atom can generate entropy squeezing under the control of the weak measurement. Besides, it is proved again that as a measurement method for atomic squeezing, the entropy squeezing is precise and effective. Therefore our work is instructive for experiments in preparing three-level system information resource with ultra-low quantum noise.

Generation of entangled coherent states for two cavity modes via resonant interaction with a V-type three-level atom

This paper proposes a scheme for the generation of entangled coherent states for two cavity modes. In the scheme a V-type three-level atom is sent through a two-mode cavity filled with a coherent field. After the atom cavity interaction and detection of the atomic state the cavity modes may evolve to a superposition of two-mode coherent states. As the scheme is based on resonant atom-cavity interaction, the required interaction time is short, which is important in view of the decoherence. Moreover, additional classical pulses are unnecessary before and after the atom-cavlty interaction.

Demonstration of the approximation of eliminating atomic excited populations in an atom-cavity system

Using the master equation approach to a V-type three-level atom inside a high-finesse single-mode cavity in the strong coupling condition, we demonstrate the approximation of eliminating populations of atomic excited states, which is widely used in the field of the atom cavity systems [Hechenblaikner G, Gangl M, Horak P and Ritsch H 1998 Phys. Rev. A 58 3030]; Liu L W, Tan T and Xu Y 2008 J. Mod. Opt. 56 968; Cho J, Angelakis D G and Bose S 2008 Phys. Rev. A 78 062338. This is reflected in the deviation of the population 5, of which the value is 10^-3 - 10^-2. We further find the deviation of the dipole force and demonstrate that the deviation of atomic population will not notably affect the dipole force of the atom in the strong coupling condition. A relevant experimental case is also presented.

Teleporting N-qubit unknown atomic state by utilizing the V-type three-level atom

Realizing the teleportation of quantum state, especially the teleportation of N-qubit quantum state, is of great importance in quantum information. In this paper, Raman-interaction of the V-type degenerate three-level atom and single-mode cavity field is studied by utilizing complete quantum theory. Then a new scheme for teleporting N-qubit unknown atomic state via Raman-interaction of the V-type degenerate three-level atom with a single-mode cavity field is proposed, which is based upon the complete quantum theory mentioned above.

Controllable single-photon transport in an optical waveguide coupled to an optomechanical cavity with a V-type three-level atom

An optomechanical cavity embedded with a V-type three-level atom is exploited to control single-photon transport in a one-dimensional waveguide. The effects of the atom–cavity detuning, the optomechanical effect,the coupling strengths between the cavity and the atom or the waveguide, and the atomic dissipation on the single-photon transport properties are analyzed systematically. Interestingly, the single-photon transmission spectra show multiple double electromagnetically induced transparency. Moreover, the double electromagnetically induced transparency can be switched to a single one by tuning the atom–cavity detuning.

Preparation of W state in resonant bimodal cavity quantum electrodynamics

A scheme is proposed for generating entangled W states with four cavity modes. In this scheme, we send a V-type three-level atom through two identical two-mode cavities in succession. After the atom exits from the second cavity, the four cavity modes are prepared in the W state. On the other hand we can obtain three-atom W states by sending three V-type three-level atoms through a two-mode cavity in turn. The present scheme does not require conditional measurement, and it is easily generalized to preparing 2n-mode W states and n-atom W states.