Steady State Atom-Photon Entanglement in Cavity QED Systems
Junli Chang, L. C. Wang, J. Chen, X. X. Yi · 2005
Using an atom-cavity QED system, we show that noise may play a positive role in entanglement generation. The dependence of the entanglement on the noise intensity and the other parameters is illustrated both analytically and numerically. The results shed new light on the problem of noise-assisted entanglement preparation in flying-localized qubit systems. PACS numbers: 03.67.Mn, 89.70.+c, 32.80.-t As one of the most fascinating features of the quantum world, entanglement plays a fundamental role in quantum information processing and quantum computing [1]; it is the feature that ensures the realization of quantum cryptography [2] and teleportation [3], as well as the exponential speed-up promised by quantum algorithms [4, 5]. Numerous proposals have been made for entanglement preparation, among them photon down-conversion is almost exclusively the proposal for experimental realization. Photons in polarization states have the merit of easy control, and their quantum coherence can be preserved over a long distance in an optical fibre [6]; however the disadvantage of long-time storage and manipulation hinder the use of entangled photons in quantum computing applications. In contrast, entangled pairs of material particles such as atoms and ions are easy to store and manipulate,