Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Periodic and Aperiodic Bunching in the Addition Spectra of Quantum Dot   We study electron addition spectra of quantum dots in a broad range of
electron occupancies starting from the first electron. Spectra for dots
containing <200 electrons reveal a surprising feature. Electron additions are
not evenly spaced in gate voltage. Rather, they group into bunches. With
increasing electron number the bunching evolves from occurring randomly to
periodically at about every fifth electron. The periodicity of the bunching and
features in electron tunneling rates suggest that the bunching is associated
with electron additions into spatially distinct regions within the dots.

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The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
2
The categories of this paper are: math
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The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics