97 research outputs found
The Backreaction of Anti-M2 Branes on a Warped Stenzel Space
We find the superpotential governing the supersymmetric warped M-theory
solution with a transverse Stenzel space found by Cvetic, Gibbons, Lu and Pope
in hep-th/0012011, and use this superpotential to extract and solve the twelve
coupled equations underlying the first-order backreacted solution of a stack of
anti-M2 branes in this space. These anti-M2 branes were analyzed recently in a
probe approximation by Klebanov and Pufu, who conjectured that they should be
dual to a metastable vacuum of a supersymmetric 2+1 dimensional theory. We find
that the would-be supergravity dual to such a metastable vacuum must have an
infrared singularity and discuss whether this singularity is acceptable or not.
Given that a similar singularity appears when placing anti-D3 branes in the
Klebanov-Strassler solution, our work strengthens the possibility that
anti-branes in warped throats do not give rise to metastable vacua.Comment: 28 pages, LaTe
Weyl Anomaly in NonRelativistic CFTs
We study Weyl symmetry for non-relativistic conformal filed theories on
curved spatial spaces, and calculate it's quantum anomaly. We show that there
is no geometric anomaly, and the non-relativistic Weyl anomaly can appear only
due to interaction. Also we study the anomaly by using the light-cone approach.Comment: 10 pages, references added, conclusion correcte
Assessing a candidate IIA dual to metastable supersymmetry-breaking
We analyze the space of linearized non-supersymmetric deformations around a
IIA solution found by Cvetic, Gibbons, Lu and Pope (CGLP) in hep-th/0101096. We
impose boundary conditions aimed at singling out among those perturbations
those describing the backreaction of anti-D2 branes on the CGLP background. The
corresponding supergravity solution is a would-be dual to a metastable
supersymmetry-breaking state. However, it turns out that this candidate bulk
solution is inevitably riddled with IR divergences of its flux densities and
action, whose physical meaning and implications for models of string cosmology
call for further investigation.Comment: 33 pages. v2: reference added, clarifications in the introductio
Heavy quark in an expanding plasma in AdS/CFT
Using the Janik-Peschanski dual to a Bjorken flow, a Langevin equation is
derived for a heavy quark in an expanding N = 4 supersymmetric Yang-Mills
plasma. Such a plasma is characterized by a proper-time dependence of the
temperature and corresponds to a system out of equilibrium. The analysis first
focuses on a quark at rest in the plasma comoving frame. The case of a quark
moving across a longitudinally expanding plasma is then considered. The
two-point functions for the random noise acting on such heavy quark probes are
computed.Comment: 17 pages. v2: references added; improved comments on the
Schwinger-Keldysh formalis
On meson melting in the quark medium
We consider a heavy quark-antiquark pair as a heavy meson in the
medium composed of light quarks and gluons. By using the AdS/CFT
correspondence, the properties of this system are investigated. In particular,
we study the inter-quark distance and it is shown that the mechanism of melting
in the quark-gluon plasma and in the hadronic phase are the same. It is found
that by considering finite coupling corrections, the inter-quark distance of a
heavy meson decreases. As a result a heavy meson like will melt at
higher temperatures. By considering rotating heavy mesons, we discuss melting
of exited states like and .Comment: 18 pages, 12 figures, We more clarify and extend the results of
arXiv:0907.006
Stochastic String Motion Above and Below the World Sheet Horizon
We study the stochastic motion of a relativistic trailing string in black
hole AdS_5. The classical string solution develops a world-sheet horizon and we
determine the associated Hawking radiation spectrum. The emitted radiation
causes fluctuations on the string both above and below the world-sheet horizon.
In contrast to standard black hole physics, the fluctuations below the horizon
are causally connected with the boundary of AdS. We derive a bulk stochastic
equation of motion for the dual string and use the AdS/CFT correspondence to
determine the evolution a fast heavy quark in the strongly coupled
plasma. We find that the kinetic mass of the quark decreases by while the correlation time of world sheet
fluctuations increases by .Comment: 27 pages, 5 figures; v2 final version, small changes, references
adde
Drag and jet quenching of heavy quarks in a strongly coupled N=2* plasma
The drag of a heavy quark and the jet quenching parameter are studied in the
strongly coupled N=2* plasma using the AdS/CFT correspondence. Both increase in
units of the spatial string tension as the theory departs from conformal
invariance. The description of heavy quark dynamics using a Langevin equation
is also considered. It is found that the difference between the velocity
dependent factors of the transverse and longitudinal momentum broadening of the
quark admit an interpretation in terms of relativistic effects, so the
distribution is spherical in the quark rest frame. When conformal invariance is
broken there is a broadening of the longitudinal momentum distribution. This
effect may be useful in understanding the jet distribution observed in
experiments.Comment: 30 pages, 5 figures, references added, minor corrections. To be
published in JHE
On Metastable Vacua and the Warped Deformed Conifold: Analytic Results
Continuing the programme of constructing the backreacted solution
corresponding to smeared anti-D3 branes in the warped deformed conifold, we
solve analytically the equations governing the space of first-order
deformations around this solution. We express the results in terms of at most
three nested integrals. These are the simplest expressions for the space of
SU(2) \times SU(2) \times \ZZ_2-invariant deformations, in which the putative
solution for smeared anti-D3 branes must live. We also explain why one cannot
claim to identify this solution without fully relating the coefficients of the
infrared and ultraviolet expansions of the deformation modes. The analytic
solution we find is the first step in this direction.Comment: 16 page
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