Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin Echo Decay in a Stochastic Field Environment   We derive a general formalism with which it is possible to obtain the time
dependence of the echo size for a spin in a stochastic field environment. Our
model is based on ``strong collisions''. We examine in detail three cases
where: (I) the local field is Ising-like, (II) the field distribution is
continuous and has a finite second moment, and (III) the distribution is
Lorentzian. The first two cases show a T2 minimum effect and are exponential in
time cubed for short times. The last case can be approximated by a
phenomenological stretched exponential.

22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
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The categories of this paper are: econ
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
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The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas