Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact classical Doppler effect derived from the photon emission process   The concept of photon is not necessary only applied to the relativistic
Doppler theory. It may also work well for classical theory. As conservation of
momentum and energy are physical laws, if applying these laws gives the exact
relativistic Doppler effect, it should also give the exact classical Doppler
effect. So far the classical Doppler effect is only obtained by using some
approximation, as derived by Fermi in 1932. We show that the exact classical
Doppler effect can be derived from the photon emission process in the exact
treatment and reveal that these results are the same as those derived from the
wave theory of light.

37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ex
2
The categories of this paper are: math
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The categories of this paper are: eess
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex