High success standard quantum teleportation using entangled coherent state and two-level atoms in cavities

Abstract

We propose here a new idea for quantum teleportation of superposed coherent state which is not only almost perfect, in principle, but also feasible experimentally. We use entangled resource $\sim |\alpha,\frac{\alpha}{\sqrt{2}}\rangle-|-\alpha,-\frac{\alpha}{\sqrt{2}}\rangle$ in contrast with the usual $\sim |\alpha,\alpha\rangle-|-\alpha,-\alpha \rangle$ (both states unnormalized). Bob receives state which is then superposition of the states $|\pm \frac{\alpha}{\sqrt{2}}\rangle$ . Bob mixes these with even or odd coherent states involving superposition of states $|\pm \frac{\alpha}{\sqrt{2}}\rangle$ to obtain a two-mode state which is one of $\sim |I,0\rangle \pm |0,I\rangle$, $|I\rangle$ being the information state. Bob then obtains the teleported information by using interaction of one of these modes in two cavities with resonant two-level atoms. This scheme results in average fidelity of $\simeq 0.95$ for $|\alpha|^2 \simeq 10$, which increases with $|\alpha|^2$ and tends to 1 asymptotically, varying as $1-\frac{\pi^2}{16|\alpha|^2}+\frac{\pi^2(\pi^2+8)}{256|\alpha|^4}$ for large values of $|\alpha|^2$.