Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microwave-Induced Oscillations in the Magnetocapacitance: Direct
  Evidence for Non-equilibrium Occupation of Electronic States   In a two-dimensional electron system, microwave radiation may induce giant
resistance oscillations. Their origin has been debated controversially and
numerous mechanisms based on very different physical phenomena have been
invoked. However none of them have been unambiguously experimentally
identified, since they produce similar effects in transport studies. The
capacitance of a two-subband system is sensitive to a redistribution of
electrons over energy states, since it entails a shift of the electron charge
perpendicular to the plane. In such a system microwave induced
magnetocapacitance oscillations have been observed. They can only be accounted
for by an electron distribution function oscillating with energy due to Landau
quantization, one of the quantum mechanisms proposed for the resistance
oscillations.

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The categories of this paper are: hep-th
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
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The categories of this paper are: econ
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: physics
17
The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph