Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Atomic diffraction by a thin phase grating   We present a semiclassical perturbation method for the description of atomic
diffraction by a weakly modulated potential. It proceeds in a way similar to
the treatment of light diffraction by a thin phase grating, and consists in
calculating the atomic wavefunction by means of action integrals along the
classical trajectories of the atoms in the absence of the modulated part of the
potential. The capabilities and the validity condition of the method are
illustrated on the well-known case of atomic diffraction by a Gaussian standing
wave. We prove that in this situation the perturbation method is equivalent to
the Raman-Nath approximation, and we point out that the usually-considered
Raman-Nath validity condition can lead to inaccuracies in the evaluation of the
phases of the diffraction amplitudes. The method is also applied to the case of
an evanescent wave reflection grating, and an analytical expression for the
diffraction pattern at any incidence angle is obtained for the first time.
Finally, the application of the method to other situations is briefly
discussed.

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The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph