Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: One-dimensional Quantum Spin Dynamics of Bethe String States   Quantum dynamics of strongly correlated systems is a challenging problem.
Although the low energy fractional excitations of one dimensional integrable
models are often well-understood, exploring quantum dynamics in these systems
remains challenging in the gapless regime, especially at intermediate and high
energies. Based on the algebraic Bethe ansatz formalism, we study spin dynamics
in a representative one dimensional strongly correlated model, {\it i.e. }, the
antiferromagnetic spin-$\frac{1}{2}$ XXZ chain with the Ising anisotropy, via
the form-factor formulae. Various excitations at different energy scales are
identified crucial to the dynamic spin structure factors under the guidance of
sum rules. At small magnetic polarizations, gapless excitations dominate the
low energy spin dynamics arising from the magnetic-field-induced
incommensurability. In contrast, spin dynamics at intermediate and high
energies is characterized by the two- and three-string states, which are
multi-particle excitations based on the commensurate N\'eel ordered background.
Our work is helpful for experimental studies on spin dynamics in both condensed
matter and cold atom systems beyond the low energy effective Luttinger liquid
theory. Based on an intuitive physical picture, we speculate that the dynamic
feature at high energies due to the multi-particle anti-bound state excitations
can be generalized to non-integrable spin systems.

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The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-th
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: nlin
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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: supr-con
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: ao-sci