Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How fast is a quantum jump?   A proposal is put forward for an estimate of the duration of a transition
between atomic states. The proposal rests on the consideration that a resonance
of the atomic electron with modes of the zero-point radiation field of
Compton's frequency is at the core of the phenomenon. The theoretical result,
given essentially by the expression (\alpha\omega_{C})^{-1}, where \alpha is
the fine structure constant and \omega_{C} the Compton angular frequency for
the electron, lies well within the range of the recently experimentally
estimated values of the order of attoseconds (10^{-18} s).

14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph