Quantum coherent effects in multi-Zeeman-sublevel atomic systems

This paper reports the experimental results on electromagnetically induced absorption (EIA) spectra observed in the system which does not satisfy completely the conditions given by Lezama {\it et al} 1999 \wx{Phys. Rev. {\rm A}}{59} 4732]. EIA signals on the transitions in the Cs $D_{2}$ line are able to be observed, where $F_{\rm g} \leftrightarrow F_{\rm e}=F_{\rm g}-1$ as open systems. Theoretical model of Lezama {\it et al} is good for the case $F_{\rm g} \leftrightarrow F_{\rm e}=F_{\rm g}+1$, considering spontaneous transfer of atomic coherences or populations this model is not able to explain our experimental results obtained in the case $F_{\rm g} \leftrightarrow F_{\rm e}=F_{\rm g}-1$. This paper offers a theoretical model which is able to well explain the case $F_{\rm g} \leftrightarrow F_{\rm e}=F_{\rm g}-1$. It also uses this theoretical model to explain the split and shift of EIA peaks, which have been obtained in experiments.