Manipulation of Cavity Field States with Multi-Level Atoms

Mahmoud Abdel‐Aty, Mohamed Ridza Wahiddin, A.‐S. F. Obada

We derive an explicit formula for an entanglement measure of mixed quantum states in a multi-level atom interacting with a cavity field within the framework of the quantum mutual entropy. We describe its theoretical basis and discuss its practical relevance (especially in comparison with already known pure state results). The effect of the number of levels involved on the entanglement is demonstrated via examples of three-, four- and five-level atom. Numerical calculations under current experimental conditions are performed and it is found that the number of levels present changes the general features of entanglement dramatically.

Y. S. El-Saman, S. Abdel‐Khalek, Ashraf Badawi +1 more

András Vukics

Zheng Shi-Biao, Guo Guang-Can

A scheme is presented for preparing multi-atom entangled states based on the Raman atom-cavity-field interaction. After several degenerate Λ-type three-level atoms interact with an appropriately prepared single-mode cavity field through Raman coupling, a two-level atom, resonant with the cavity, is sent through the cavity and a Ramsey zone. The detection of the two-level atom leaves the Λ-type atoms in an entangled state.

Muhammad Imran, Hinna Tariq, Rameez‐ul‐Islam +1 more

Abstract We present an idea for the doubly tagged delayed-choice tunable quantum eraser in a cavity QED setup, based on fully controlled resonant as well as dispersive atom–field interactions. Two cavity fields, bound initially in the Bell state, are coupled to a three-level atom. Such an atom is initially prepared in the coherent superposition of the lower two levels and is quite capable of exhibiting Ramsey fringes if taken independently. It is shown that the coherence lost due to tagging can not only be retrieved but that the fringe visibility/path distinguishability can also be conditionally tuned in a delayed manner through local manipulation of the entangled cavity fields. The stringent condition here is the retainment of the system’s coherence during successive manipulations of the individual cavity fields. Such a quantum eraser, therefore, prominently highlights the links among all the counterintuitive features of quantum theory including the conception of time, measurement, state vector reduction, coherence and information in an unambiguous manner. The schematics can be straightforwardly extended to a multipartite scenario and employed to explore multi-player quantum games with the payoff being strangely decided through delayed choice setups.

S. Abdel‐Khalek