2,246 research outputs found
Quasinormal modes of plane-symmetric black holes according to the AdS/CFT correspondence
The electromagnetic and gravitational quasinormal spectra of
-dimensional plane-symmetric anti-de Sitter black holes are analyzed in
the context of the AdS/CFT correspondence. According to such a correspondence,
the electromagnetic and gravitational quasinormal frequencies of these black
holes are associated respectively to the poles of retarded correlation
functions of -symmetry currents and stress-energy tensor in the
holographically dual conformal field theory: the -dimensional
super-Yang-Mills theory. The connection between AdS black holes
and the corresponding field theory is used to unambiguously fix the boundary
conditions that enter the proper definition of quasinormal modes. Such a
procedure also helps one to decide, among the various different possibilities,
what are the appropriate gauge-invariant quantities one should use in order to
correctly describe the electromagnetic and gravitational blackhole
perturbations. These choices imply in different dispersion relations for the
quasinormal modes when compared to some of the results in the literature. In
particular, the long-distance, low-frequency limit of dispersion relations
presents the characteristic hydrodynamic behavior of a conformal field theory
with the presence of diffusion, shear, and sound wave modes. There is also a
family of purely damped electromagnetic modes which tend to the bosonic
Matsubara frequencies in the long-wavelength regime.Comment: 39 pages; added references; corrected typos; changed content in
section
Melting of scalar mesons and black-hole quasinormal modes in a holographic QCD model
A holographic model for QCD is employed to investigate the effects of the
gluon condensate on the spectrum and melting of scalar mesons. We find the
evolution of the free energy density with the temperature, and the result shows
that the temperature of the confinement/deconfinement transition is sensitive
to the gluon-condensate parameter. The spectral functions (SPFs) are also
obtained and show a series of peaks in the low-temperature regime, indicating
the presence of quasiparticle states associated to the mesons, while the number
of peaks decreases with the increment of the temperature, characterizing the
quasiparticle melting. In the dual gravitational description, the scalar mesons
are identified with the black-hole quasinormal modes (QNMs). We obtain the
spectrum of QNMs and the dispersion relations corresponding to the scalar-field
perturbations of the gravitational background, and find their dependence with
the gluon-condensate parameter.Comment: 30 pages, 12 figures, 5 table
Vector meson quasinormal modes in a finite-temperature AdS/QCD model
We study the spectrum of vector mesons in a finite temperature plasma. The
plasma is holographically described by a black hole AdS/QCD model. We compute
the boundary retarded Green's function using AdS/CFT prescriptions. The
corresponding thermal spectral functions show quasiparticle peaks at low
temperatures. Then we calculate the quasinormal modes of vector mesons in the
soft-wall black hole geometry and analyse their temperature and momentum
dependences.Comment: 27 pages, 9 figure
A Critique on Public–Private–People Partnerships: From a Definitional Inconsistency to the Partnering Dilemma in Today’s Housing Conjunction
- …