110 research outputs found
Heavy Quarkonium States with the Holographic Potential
The quarkonium states in a quark-gluon plasma is examined with the heavy
quark potential implied by the holographic principle. Both the vanila
AdS-Schwarzschild metric and the one with an infrared cutoff are considered.
The dissociation temperature is calculated by solving the Schr\"o dinger
equation of the potential model. In the case of the AdS-Schwarzschild metric
with a IR cutoff, the dissociation temperatures for and
with the U-ansatz of the potential are found to agree with the lattice results
within a factor of two.Comment: 9 pages with 2 figues in Revte
Perturbations of moving membranes in AdS_7
We study the stability of uniformly moving membrane-like objects in seven
dimensional Anti-de Sitter space. This is approached by a linear perturbation
analysis and a search for growing modes. We examine both analytic and numerical
configurations previously found in [1].Comment: 20 pages, 6 figure
Revisiting the deconfinement phase transition in SU(4) Yang-Mills theory in 2+1 dimensions
In order to deepen our understanding of the nature of the deconfinement phase
transition for various gauge groups, we investigate SU(4) Yang-Mills theory in
2+1 dimensions. We find that the transition is weakly first order. We perform
extensive Monte Carlo simulations on lattices with temporal extent N_t = 3, 4
and 5, and spatial sizes up to N_s = 20 N_t. We observe coexistence of confined
and deconfined phases at the critical temperature, and finite-size scaling
shows consistency with first order exponents. The continuum extrapolation of
the latent heat yields L_h/T_c^3=0.188(17).Comment: 29 pages, 15 figures; v2: version published in JHEP, analysis section
expande
Strongly bound mesons at finite temperature and in magnetic fields from AdS/CFT
We study mesons in N=4 super Yang-Mills theory with fundamental flavors added
at large 't Hooft coupling using the gauge/gravity correspondence. High-spin
mesons are well described by using semiclassical string configurations. We
determine the meson spectrum at finite temperature and in a background magnetic
field.Comment: 15 pages, 11 figures; v2: references adde
Heavy quarks in a magnetic field
The motion of a heavy charged quark in a magnetic field is analyzed in the
vacuum of strongly coupled CFT. The motion of the quark is dissipative. It
moves in spiral until it eventually comes to rest. The world-sheet geometry is
locally AdS_2 but has a time dependent horizon. The string profile in the
static gauge extends from the boundary till a point where an embedding
singularity exists. Connections with other circular string motions are
established.Comment: (v3) Misprints corrected, discussion on moving horizons improved and
enhance
Critical Exponents from AdS/CFT with Flavor
We use the AdS/CFT correspondence to study the thermodynamics of massive N=2
supersymmetric hypermultiplet flavor fields coupled to N=4 supersymmetric
SU(Nc) Yang-Mills theory, formulated on curved four-manifolds, in the limits of
large Nc and large 't Hooft coupling. The gravitational duals are probe
D-branes in global thermal AdS. These D-branes may undergo a topology-changing
transition in the bulk. The D-brane embeddings near the point of the topology
change exhibit a scaling symmetry. The associated scaling exponents can be
either real- or complex-valued. Which regime applies depends on the
dimensionality of a collapsing submanifold in the critical embedding. When the
scaling exponents are complex-valued, a first-order transition associated with
the flavor fields appears in the dual field theory. Real scaling exponents are
expected to be associated with a continuous transition in the dual field
theory. For one example with real exponents, the D7-brane, we study the
transition in detail. We find two field theory observables that diverge at the
critical point, and we compute the associated critical exponents. We also
present analytic and numerical evidence that the transition expresses itself in
the meson spectrum as a non-analyticity at the critical point. We argue that
the transition we study is a true phase transition only when the 't Hooft
coupling is strictly infinite.Comment: 31 pages, 21 eps files in 12 figures; v2 added one reference and one
footnote, version published in JHE
Holographic dual of the Eguchi-Kawai mechanism
archiveprefix: arXiv primaryclass: hep-th reportnumber: NORDITA-2014-40, UUITP-03-14, QMUL-PH-14-08 slaccitation: %%CITATION = ARXIV:1404.0225;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: NORDITA-2014-40, UUITP-03-14, QMUL-PH-14-08 slaccitation: %%CITATION = ARXIV:1404.0225;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: NORDITA-2014-40, UUITP-03-14, QMUL-PH-14-08 slaccitation: %%CITATION = ARXIV:1404.0225;%%The work of K.Z. was supported by
the ERC advanced grant No 341222, by the Marie Curie network GATIS of the European
Unionâs FP7 Programme under REA Grant Agreement No 317089, and by the Swedish
Research Council (VR) grant 2013-4329. DY acknowledges NORDITA where this work
was begun, during his time as a NORDITA fellow
The Stress-Energy Tensor of Flavor Fields from AdS/CFT
We use the AdS/CFT correspondence to study the transport properties of
massive N=2 hypermultiplet fields in an N=4 SU(Nc) super-Yang-Mills theory
plasma in the large Nc, large 't Hooft coupling limit, and in the presence of a
baryon number chemical potential and external electric and magnetic fields. In
particular, we compute the flavor fields' contribution to the stress-energy
tensor. We find infrared divergences in the stress-energy tensor, arising from
the flavor fields' constant rate of energy and momentum loss. We regulate these
divergences and extract the energy and momentum loss rates from the divergent
terms. We also check our result in various limits in which the divergences are
absent. The supergravity dual is a system of D7-branes, with a particular
configuration of worldvolume fields, probing an AdS-Schwarzschild background.
The supergravity calculation amounts to computing the stress-energy tensor of
the D7-branes.Comment: 32 pages; v2, added one footnote in section 2.2, added one reference,
version published in JHE
Stationary strings and branes in the higher-dimensional Kerr-NUT-(A)dS spacetimes
We demonstrate complete integrability of the Nambu-Goto equations for a
stationary string in the general Kerr-NUT-(A)dS spacetime describing the
higher-dimensional rotating black hole. The stationary string in D dimensions
is generated by a 1-parameter family of Killing trajectories and the problem of
finding a string configuration reduces to a problem of finding a geodesic line
in an effective (D-1)-dimensional space. Resulting integrability of this
geodesic problem is connected with the existence of hidden symmetries which are
inherited from the black hole background. In a spacetime with p mutually
commuting Killing vectors it is possible to introduce a concept of a
-brane, that is a p-brane with the worldvolume generated by these fields
and a 1-dimensional curve. We discuss integrability of such -branes in the
Kerr-NUT-(A)dS spacetime.Comment: 8 pages, no figure
Hot Defect Superconformal Field Theory in an External Magnetic Field
In this paper we investigate the influence of an external magnetic field on a
flavoured holographic gauge theory dual to the D3/D5 intersection at finite
temperature. Our study shows that the external magnetic field has a freezing
effect on the confinement/ deconfinement phase transition. We construct the
corresponding phase diagram. We investigate some thermodynamic quantities of
the theory. A study of the entropy reveals enhanced relative jump of the
entropy at the "chiral" phase transition. A study of the magnetization shows
that both the confined and deconfined phases exhibit diamagnetic response. The
diamagnetic response in the deconfined phase has a stronger temperature
dependence reflecting the temperature dependence of the conductivity. We study
the meson spectrum of the theory and analyze the stability of the different
phases looking at both normal and quasi-normal semi-classical excitations. For
the symmetry breaking phase we analyze the corresponding pseudo-Goldstone modes
and prove that they satisfy non-relativistic dispersion relation.Comment: 42 pages, 14 figure
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