Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time resolved excitonic coherent polarization dynamics in GaAs multiple
  quantum wells   We investigate pump induced modulation in the temporal evolution of the
excitonic coherent polarization generated by a probe pulse in GaAs multiple
quantum wells. For this, we perform fs time resolved pump-probe reflectivity
measurements using frequency upconversion at both positive and negative
pump-probe delays. A contribution arising from interference of excitonic linear
and nonlinear polarization, which is usually not considered in describing
pump-probe experiments, is required to understand the results.

35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
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The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
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The categories of this paper are: funct-an