Cutoff Function in Holographic RG Flow
Using the precursor map in AdS/CFT, the renormalization group cutoff function is mapped to the dual theory. The resulting flow equations on the two sides of the duality are compared.
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arXiv subjects
Farhad Ardalan
Publications and source records attributed to Farhad Ardalan.
Holographic Phase Transition to Topological Dyons
The dynamical stability of a Julia-Zee solution in the AdS background in a four dimensional Einstein-Yang-Mills-Higgs theory is studied. We find that the model with a vanishing scalar field develops a non-zero value for the field at a certain critical temperature which corresponds to a topological dyon in the bulk and a topological phase transition at the boundary.
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Central Charge for 2D Gravity on AdS(2) and AdS(2)/CFT(1) Correspondence
We study 2D Maxwell-dilaton gravity on AdS(2). We distinguish two distinctive cases depending on whether the AdS(2) solution can be lifted to an AdS(3) geometry. In both cases, in order to get a consistent boundary condition we need to work with a twisted energy momentum tensor which has non-zero central charge. With this central charge and the explicit form of the twisted Virasoro generators we compute the entropy of the system using the Cardy formula. The entropy is found to be the same as that obtained from gravity calculations for a specific value of the level of the U(1) current. The agreement is an indication of $AdS(2)/CFT(1) correspondence.
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On 5D Small Black Holes
Using higher order corrections we argue that five dimensional N=2 and N=4 small black holes exhibit supersymmetry enhancement in near horizon geometry leading to eight and sixteen supercharges, respectively. Using this enhancement at supergravity level we can identify the global supergroup of the near horizon geometry. In particular we show how this supergroup distinguishes between small and large black holes in N=2 case.
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Planar and Nonplanar Konishi Anomalies and Effective Superpotential for Noncommutative N=1 Supersymmetric U(1)
The Konishi anomalies for noncommutative N=1 supersymmetric U(1) gauge theory arising from planar and nonplanar diagrams are calculated. Whereas planar Konishi anomaly is the expected \star-deformation of the commutative anomaly, nonplanar anomaly reflects the important features of nonplanar diagrams of noncommutative gauge theories, such as UV/IR mixing and the appearance of nonlocal open Wilson lines. We use the planar and nonplanar Konishi anomalies to calculate the effective superpotential of the theory. In the limit of vanishing |Θp|, with Θthe noncommutativity parameter, the noncommutative effective superpotential depends on a gauge invariant superfield, which includes supersymmetric Wilson lines, and has nontrivial dependence on the gauge field supermultiplet.
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Anomaly and Nonplanar Diagrams in Noncommutative Gauge Theories
Anomalies arising from nonplanar triangle diagrams of noncommutative gauge theory are studied. Local chiral gauge anomalies for both noncommutative U(1) and U(N) gauge theories with adjoint matter fields are shown to vanish. For noncommutative QED with fundamental matters, due to UV/IR mixing a finite anomaly emerges from the nonplanar contributions. It involves a generalized $\star$-product of gauge fields.
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Axial Anomaly in Noncommutative QED on R^4
The axial anomaly of the noncommutative U(1) gauge theory is calculated by a number of methods and compared with the commutative one. It is found to be given by the corresponding Chern class.
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Large Extra Dimensions and Noncommutative Geometry in String Theory
The consequences of noncommutativity of space coordinates of string theory in the proposed large extra dimension solution to the hierarchy problem are explored; in particular the large dimension stabilization and the graviton reabsorption in the brane are considered.
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Point-Like Structure in Strings and Non-Commutative Geometry
Dynamics of a free point particle on a multi world-line is presented and shown to reduce to that of a bosonic string theory at the appropriate limit. Other higher dimensional extended objects are argued to appear at other regions of the space of configurations of the theory.
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2D Black Holes and 2D Gravity
\small The SL$(2,R)/U(1)$ coset model, with $U(1)$ an element of the third conjugacy class of $SL(2,R)$ subgroups, is considered. The resulting theory is seen to collapse to a one dimensional field theory of Liouville. Then the 2 dimensional black hole $SL(2,R)/U(1)$, with $U(1)$ a non-compact subgroup boosted by a Lorentz transformation, is considered. In the limit of high boost, the resulting black hole is found to tend to the Liouville field coupled to $a\ C=1$ matter field. The limit of the vertex operators of the 2 dimensional black hole also tend to those of the $C=1$ two dimensional gravity.
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