145 research outputs found
Self-bound dense objects in holographic QCD
We study a self-bound dense object in the hard wall model. We consider a
spherically symmetric dense object which is characterized by its radial density
distribution and non-uniform but spherically symmetric chiral condensate. For
this we analytically solve the partial differential equations in the hard wall
model and read off the radial coordinate dependence of the density and chiral
condensate according to the AdS/CFT correspondence. We then attempt to describe
nucleon density profiles of a few nuclei within our framework and observe that
the confinement scale changes from a free nucleon to a nucleus. We briefly
discuss how to include the effect of higher dimensional operator into our
study. We finally comment on possible extensions of our work.Comment: 17 pages, 5 figures, figures replaced, minor revision, to appear in
JHE
Effective AdS/renormalized CFT
For an effective AdS theory, we present a simple prescription to compute the
renormalization of its dual boundary field theory. In particular, we define
anomalous dimension holographically as the dependence of the wave-function
renormalization factor on the radial cutoff in the Poincare patch of AdS. With
this definition, the anomalous dimensions of both single- and double- trace
operators are calculated. Three different dualities are considered with the
field theory being CFT, CFT with a double-trace deformation and spontaneously
broken CFT. For the second dual pair, we compute scaling corrections at the UV
and IR fixed points of the RG flow triggered by the double-trace deformation.
For the last case, we discuss whether our prescription is sensitive to the AdS
interior or equivalently, the IR physics of the dual field theory.Comment: 20 pages, 3 figure
Virtual Compton Scattering off a Spinless Target in AdS/QCD
We study the doubly virtual Compton scattering off a spinless target
within the Anti-de Sitter(AdS)/QCD formalism. We find
that the general structure allowed by the Lorentz invariance and gauge
invariance of the Compton amplitude is not easily reproduced with the standard
recipes of the AdS/QCD correspondence. In the soft-photon regime, where the
semi-classical approximation is supposed to apply best, we show that the
measurements of the electric and magnetic polarizabilities of a target like the
charged pion in real Compton scattering, can already serve as stringent tests.Comment: 21 pages, version to be published in JHEP
Symmetry energy of dense matter in holographic QCD
We study the nuclear symmetry energy of dense matter using holographic QCD.
To this end, we consider two flavor branes with equal quark masses in a
D4/D6/D6 model. We find that at all densities the symmetry energy monotonically
increases. At small densities, it exhibits a power law behavior with the
density, .Comment: 9 pages, 3 figure
Scalar and vector mesons of flavor chiral symmetry breaking in the Klebanov-Strassler background
Recently, Dymarsky, Kuperstein and Sonnenschein constructed an embedding of
flavor D7- and anti-D7-branes in the Klebanov-Strassler geometry that breaks
the supersymmetry of the background, yet is stable. In this article, we study
in detail the spectrum of vector mesons in this new model of flavor chiral
symmetry breaking and commence an analytical analysis of the scalar mesons in
this setup.Comment: v1: 35 pages, 5 figures, 4 tables, includes self-contained review of
DKS construction; v2: corrected signs in eqs. (2.22) and (2.23), improved
discussion of scalar mesons in section 3.2; v3: major revision of the results
on scalar mesons, version submitted to JHEP; v4: version accepted by JHE
Long-Range Rapidity Correlations in Heavy Ion Collisions at Strong Coupling from AdS/CFT
We use AdS/CFT correspondence to study two-particle correlations in heavy ion
collisions at strong coupling. Modeling the colliding heavy ions by shock waves
on the gravity side, we observe that at early times after the collision there
are long-range rapidity correlations present in the two-point functions for the
glueball and the energy-momentum tensor operators. We estimate rapidity
correlations at later times by assuming that the evolution of the system is
governed by ideal Bjorken hydrodynamics, and find that glueball correlations in
this state are suppressed at large rapidity intervals, suggesting that
late-time medium dynamics can not "wash out" the long-range rapidity
correlations that were formed at early times. These results may provide an
insight on the nature of the "ridge" correlations observed in heavy ion
collision experiments at RHIC and LHC, and in proton-proton collisions at LHC.Comment: 32 pages, 2 figures; v2: typos corrected, references adde
Soft wall model for a holographic superconductor
We apply the soft wall holographic model from hadron physics to a description
of the high- superconductivity. In comparison with the existing bottom-up
holographic superconductors, the proposed approach is more phenomenological. On
the other hand, it is much simpler and has more freedom for fitting the
conductivity properties of the real high- materials. We demonstrate some
examples of emerging models and discuss a possible origin of the approach.Comment: 17 pages, 16 figure
Linear Confinement for Mesons and Nucleons in AdS/QCD
By using a new parametrization of the dilaton field and including a cubic
term in the bulk scalar potential, we realize linear confinement in both meson
and nucleon sectors within the framework of soft-wall AdS/QCD. At the same time
this model also correctly incorporate chiral symmetry breaking. We compare our
resulting mass spectra with experimental data and find good agreement between
them.Comment: 14 pages, published version in JHE
Gravitational collapse and thermalization in the hard wall model
We study a simple example of holographic thermalization in a confining field
theory: the homogeneous injection of energy in the hard wall model. Working in
an amplitude expansion, we find black brane formation for sufficiently fast
energy injection and a scattering wave solution for sufficiently slow
injection. We comment on our expectations for more sophisticated holographic
QCD models.Comment: 33 pages, 5 figure
Completing the framework of AdS/QCD: h_1/b_1 mesons and excited omega/rho's
We extend the "hard wall" gravity dual of QCD by including tensor fields
b_{MN} that correspond to the QCD quark bilinear operators qbar sigma^{mu nu}
q. These fields give rise to a spectrum of states which include the h_1 and b_1
mesons, as well as a tower of excited omega/rho meson states. We also identify
the lowest-dimension term which leads to mixing between the new rho states and
the usual tower of rho mesons when chiral symmetry is broken.Comment: 37 pages, uses jheppub.sty; v2: Added reference and revised
discussion of interaction term
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