Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum coherence in a degenerate two-level atomic ensemble: for a
  transition $F_e=0\leftrightarrow F_g=1$   For a transition $F_e=0\leftrightarrow F_g=1$ driven by a linearly polarized
light and probed by a circularly light, quantum coherence effects are
investigated. Due to the coherence between the drive Rabi frequency and Zeeman
splitting, electromagnetically induced transparency, electromagnetically
induced absorption, and the transition from positive to negative dispersion are
obtained, as well as the populations coherently oscillating in a wide spectral
region. At the zero pump-probe detuning, the subluminal and superluminal light
propagation is predicted. Finally, coherent population trapping states are not
highly sensitive to the refraction and absorption in such ensemble.

4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph