Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light-Front Holography and AdS/QCD: A First Approximation to QCD   The combination of Anti-de Sitter space (AdS) methods with light-front
holography leads to a semi-classical first approximation to the spectrum and
wavefunctions of meson and baryon light-quark bound states. Starting from the
bound-state Hamiltonian equation of motion in QCD, we derive relativistic
light-front wave equations in terms of an invariant impact variable zeta which
measures the separation of the quark and gluonic constituents within the hadron
at equal light-front time. These equations of motion in physical space-time are
equivalent to the equations of motion which describe the propagation of spin-J
modes in anti--de Sitter (AdS) space. Its eigenvalues give the hadronic
spectrum, and its eigenmodes represent the probability distribution of the
hadronic constituents at a given scale. Applications to the light meson and
baryon spectra are presented. The predicted meson spectrum has a string-theory
Regge form M^2 = 4 kappa^2(n+L+S/2); i.e., the square of the eigenmass is
linear in both L and n, where n counts the number of nodes of the wavefunction
in the radial variable zeta. The space-like pion form factor is also well
reproduced. One thus obtains a remarkable connection between the description of
hadronic modes in AdS space and the Hamiltonian formulation of QCD in physical
space-time quantized on the light-front at fixed light-front time. The model
can be systematically improved by using its complete orthonormal solutions to
diagonalize the full QCD light-front Hamiltonian or by applying the
Lippmann-Schwinger method in order to systematically include the QCD
interaction terms.

36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
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The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom