Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lie-Schwinger block-diagonalization and gapped quantum chains   We study quantum chains whose Hamiltonians are perturbations by bounded
interactions of short range of a Hamiltonian that does not couple the degrees
of freedom located at different sites of the chain and has a strictly positive
energy gap above its ground-state energy. We prove that, for small values of a
coupling constant, the spectral gap of the perturbed Hamiltonian above its
ground-state energy is bounded from below by a positive constant uniformly in
the length of the chain. In our proof we use a novel method based on local
Lie-Schwinger conjugations of the Hamiltonians associated with connected
subsets of the chain.

37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
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The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci