Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopic test of Bose-Einstein statistics for photons   Using Bose-Einstein-statistics-forbidden two-photon excitation in atomic
barium, we have limited the rate of statistics-violating transitions, as a
fraction $\nu$ of an equivalent statistics-allowed transition rate, to
$\nu<4.0\times10^{-11}$ at the 90% confidence level. This is an improvement of
more than three orders of magnitude over the best previous result.
Additionally, hyperfine-interaction enabling of the forbidden transition has
been observed, to our knowledge, for the first time.

31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an