2,111 research outputs found
Introduction to the AdS/CFT correspondence
This is a pedagogical introduction to the AdS/CFT correspondence, based on
lectures delivered by the author at the third IDPASC school. Starting with the
conceptual basis of the holographic dualities, the subject is developed
emphasizing some concrete topics, which are discussed in detail. A very brief
introduction to string theory is provided, containing the minimal ingredients
to understand the origin of the AdS/CFT duality. Other topics covered are the
holographic calculation of correlation functions, quark-antiquark potentials
and transport coefficients.Comment: 64 pages, 12 figures;v2: minor improvements;v3: references adde
Exact Results and Holography of Wilson Loops in N=2 Superconformal (Quiver) Gauge Theories
Using localization, matrix model and saddle-point techniques, we determine
exact behavior of circular Wilson loop in N=2 superconformal (quiver) gauge
theories. Focusing at planar and large `t Hooft couling limits, we compare its
asymptotic behavior with well-known exponential growth of Wilson loop in N=4
super Yang-Mills theory. For theory with gauge group SU(N) coupled to 2N
fundamental hypermultiplets, we find that Wilson loop exhibits non-exponential
growth -- at most, it can grow a power of `t Hooft coupling. For theory with
gauge group SU(N) x SU(N) and bifundamental hypermultiplets, there are two
Wilson loops associated with two gauge groups. We find Wilson loop in untwisted
sector grows exponentially large as in N=4 super Yang-Mills theory. We then
find Wilson loop in twisted sector exhibits non-analytic behavior with respect
to difference of two `t Hooft coupling constants. By letting one gauge coupling
constant hierarchically larger/smaller than the other, we show that Wilson
loops in the second type theory interpolate to Wilson loop in the first type
theory. We infer implications of these findings from holographic dual
description in terms of minimal surface of dual string worldsheet. We suggest
intuitive interpretation that in both type theories holographic dual background
must involve string scale geometry even at planar and large `t Hooft coupling
limit and that new results found in the gauge theory side are attributable to
worldsheet instantons and infinite resummation therein. Our interpretation also
indicate that holographic dual of these gauge theories is provided by certain
non-critical string theories.Comment: 52 pages, 7 figures v2. more figures embedded v3. minor stylistic
changes, v4. published versio
Wilson Loops in N=2 Super-Yang-Mills from Matrix Model
We compute the expectation value of the circular Wilson loop in N=2
supersymmetric Yang-Mills theory with N_f=2N hypermultiplets. Our results
indicate that the string tension in the dual string theory scales as the
logarithm of the 't Hooft coupling.Comment: 37 pages, 9 figures; v2: Numerical factors corrected, simple
derivation of Wilson loop and discussion of continuation to complex lambda
added; v3: instanton partition function re-analyzed in order to take into
account a contribution of the hypermultiplet
Supersymmetric Open Wilson Lines
In this paper we study Open Wilson Lines (OWL's) in the context of two
Supersymmetric Yang Mills theories. First we consider four dimensional N=2
Supersymmetric Yang Mills Theory with hypermultiplets transforming in the
fundamental representation of the gauge group, and find supersymmetric OWL's
only in the superconformal versions of these theories. We then consider four
dimensional N=4 SYM coupled to a three dimensional defect hypermultiplet. Here
there is a semi-circular supersymmetric OWL, which is related to the ray by a
conformal transformation. We perform a perturbative calculation of the
operators in both theories, and discuss using localization to compute them
non-perturbatively.Comment: 26 pages, 3 figure
Thermodynamic Properties of Holographic Multiquark and the Multiquark Star
We study thermodynamic properties of the multiquark nuclear matter. The
dependence of the equation of state on the colour charges is explored both
analytically and numerically in the limits where the baryon density is small
and large at fixed temperature between the gluon deconfinement and chiral
symmetry restoration. The gravitational stability of the hypothetical
multiquark stars are discussed using the Tolman-Oppenheimer-Volkoff equation.
Since the equations of state of the multiquarks can be well approximated by
different power laws for small and large density, the content of the multiquark
stars has the core and crust structure. We found that most of the mass of the
star comes from the crust region where the density is relatively small. The
mass limit of the multiquark star is determined as well as its relation to the
star radius. For typical energy density scale of ,
the converging mass and radius of the hypothetical multiquark star in the limit
of large central density are approximately solar mass and 15-27 km.
The adiabatic index and sound speed distributions of the multiquark matter in
the star are also calculated and discussed. The sound speed never exceeds the
speed of light and the multiquark matters are thus compressible even at high
density and pressure.Comment: 27 pages, 17 figures, 1 table, JHEP versio
Gravel pits support waterbird diversity in an urban landscape
We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space
Global AdS Picture of 1/2 BPS Wilson Loops
We study the holographic dual string configuration of 1/2 BPS circular Wilson
loops in N=4 super Yang-Mills theory by using the global coordinate of AdS. The
dual string worldsheet is given by the Poincare disk AdS_2 sitting at a
constant global time slice of AdS_5. We also analyze the correlator of two
concentric circular Wilson loops from the global AdS perspective and study the
phase transition associated with the instability of annulus worldsheet
connecting the two Wilson loops.Comment: 14 pages, 3 figures, v2: discussion on two branches corrected, v3:
reference adde
Ladders for Wilson Loops Beyond Leading Order
We set up a general scheme to resum ladder diagrams for the quark-anti-quark
potential in N=4 super-Yang-Mills theory, and do explicit calculations at the
next-to-leading order. The results perfectly agree with string theory in
AdS(5)xS(5) when continued to strong coupling, in spite of a potential
order-of-limits problem.Comment: 18 pages, 5 figure
A new path to measure antimatter free fall
We propose an experiment to measure the free fall acceleration of neutral antihydrogen atoms. The originality of this path is to first produce the Hbar+ ion
Gluon Scattering Amplitudes in Finite Temperature Gauge/Gravity Dualities
We examine the gluon scattering amplitude in N=4 super Yang-Mills at finite
temperature with nonzero R-charge densities, and in Non-Commutative gauge
theory at finite temperature. The gluon scattering amplitude is defined as a
light-like Wilson loop which lives at the horizon of the T-dual black holes of
the backgrounds we consider. We study in detail a special amplitude, which
corresponds to forward scattering of a low energy gluon off a high energy one.
For this kinematic configuration in the considered backgrounds, we find the
corresponding minimal surface which is directly related to the gluon scattering
amplitude. We find that for increasing the chemical potential or the
non-commutative parameter, the on-shell action corresponding to our Wilson loop
in the T-dual space decreases. For all of our solutions the length of the short
side of the Wilson loop is constrained by an upper bound which depends on the
temperature, the R-charge density and the non-commutative parameter. Due to
this constraint, in the limit of zeroth temperature our approach breaks down
since the upper bound goes to zero, while by keeping the temperature finite and
letting the chemical potential or the non-commutative parameter to approach to
zero the limit is smooth.Comment: 30 pages, 16 figures, minor corrections (plus improved numerical
computation for the non-commutative case
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