Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Effective Bosonic Hamiltonian for Excitons Reconsidered   The effective bosonic hamiltonian for excitons, extensively quoted up to now,
cannot be correct because it is (surprisingly) non-hermitian. The oversight
physically originates from the intrinsic difficulty of properly defining
electron-hole interactions between excitons when dealing with exchange terms.
By using our commutation technique, we show that the fermionic character of the
excitons cannot be forced into a dressed Coulomb interaction only : The
effective bosonic hamiltonian must contain purely fermionic terms of the same
order as the Coulomb terms. They are necessary to ensure hermiticity, and they
do not reduce to a two-body interaction, Pauli exclusion being N-body by
essence.

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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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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: eess