Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superradiance in ultracold Rydberg gases   Experiments in dense, ultracold gases of rubidium Rydberg atoms show a
considerable decrease of the radiative excited state lifetimes compared to
dilute gases. This accelerated decay is explained by collective and cooperative
effects, leading to superradiance. A novel formalism to calculate effective
decay times in a dense Rydberg gas shows that for these atoms the decay into
nearby levels increases by up to three orders of magnitude. Excellent agreement
between theory and experiment follows from this treatment of Rydberg decay
behavior.

9
The categories of this paper are: nlin
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an