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A. Smailagic

Publications and source records attributed to A. Smailagic.

17 recordsLinked to original sources
arXiv2003

String theory T-duality and the zero point length of spacetime

It has been often conjectured that the correct theory of quantum gravity will act as a UV regulator in the low energy limit of quantum field theory. Earlier work has shown that if the path integral defining the quantum field theory propagator is modified, so that the amplitude is invariant under the duality transformation l--> 1/l where l is the length of the path, then the propagator is UV-finite and exhibits a ``zero-point length'' of the spacetime. Since string theory uses extended structures and has a T-duality, these results should also emerge directly from string theory. We show, by explicit path integral computation, that this is indeed the case. The lowest order string theory correction to the propagator is the same as that obtained by the hypothesis of path integral duality.

hep-th↗
arXiv2002

Noncommutative 3D harmonic oscillator

We find transformation matrices allowing to express non-commutative three dimensional harmonic oscillator in terms of an isotropic commutative oscillator, following ``philosophy of simplicity'' approach. Non-commutative parameters have physical interpretation in terms of an external magnetic field. Furthermore, we show that for a particular choice of noncommutative parameters there is an equivalent anisotropic representation, whose transformation matrices are far more complicated. We indicate a way to obtain the more complex solutions from the simple ones.

hep-th↗
arXiv2001

Isotropic representation of noncommutative 2D harmonic oscillator

We show that 2D noncommutative harmonic oscillator has an isotropic representation in terms of commutative coordinates. The noncommutativity in the new mode, induces energy level splitting, and is equivalent to an external magnetic field effect. The equivalence of the spectra of the isotropic and anisotropic representation is traced back to the existence of SU(2) invariance of the noncommutative model.

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arXiv2001

The Dual Phases of Massless/Massive Kalb-Ramond Fields

We have developed dualization of ordinary and ``Stueckelberg compensated'' massive phase for the Kalb-Ramond theory. The compensated phase allows to study the interplay between spin jumping and duality. We show that spin jumping is caused by mass, while gauge symmetry is not necessary for this effect to take place.

hep-th↗
arXiv2000

Dualization of non-Abelian BF model

We show that dualization of BF models to Stueckelberg-like massive gauge theories allows a non-Abelian extension. We obtain local Lagrangians which are straightforward extensions of the Abelian results.

hep-th↗
arXiv2000

Wess--Zumino terms and Duality

We show the equivalence between Stuckelberg and Wess-Zumino methods of restoration of gauge symmetries of the anomalous, Abelian, effective action, in arbitrary even dimensions D=2k. We present dual version of Wess-Zumino terms with the compensating field described by a Kalb-Ramond like p=2k-2 form.

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arXiv2000

Higher Dimensional Schwinger-like Anomalous Effective Action

We construct explicit form of the anomalous effective action, in arbitrary even dimension, for Abelian vector and axial gauge fields coupled to Dirac fermions. It turns out to be a surprisingly simple extension of 2D Schwinger model effective action.

hep-th↗
arXiv1999

Dualization of Interacting Theories Including p=d-1 Limiting Cases

We study the vacuum partition functional Z [J] for a system of closed, bosonic p-branes coupled to p-forms in the limiting case: p+1 = space-time dimension. We suggest an extension of the duality transformation which can be applied to the limiting case even though no dual gauge potential exists in the conventional sense. The dual action thus obtained describes a current-current, static interaction within the bulk volume bounded by the d-1-brane. Guided by these results, we then construct a general expression for the parent Lagrangian that allows for a unified treatment of p-duality, even in the presence of external currents, using a first order formalism instead of the Bianchi identities. Finally, we show how this generalized dualization approach can accommodate the inclusion of a massive topological term in the parent action of an Abelian gauge theory.

hep-th↗
arXiv1998

Spacetime Duality and Two-dimensional Gauge Field Theory

In this letter we implement a recently proposed {\it spacetime duality} approach to dualize a two dimensional, Abelian, gauge field theory, which has no dual version under $p$--duality. Our result suggests that spacetime duality spans a new, wider, class of dual theories, which cannot be related one to another by $p$--duality transformations.

hep-th↗
arXiv1996

Consistent two--dimensional chiral gravity

We study chiral induced gravity in the light-cone gauge and show that the theory is consistent for a particular choice of chiralities. The corresponding Kac--Moody central charge has no forbidden region of complex values. Generalized analysis of the critical exponents is given and their relation to the $SL(2,R)$ vacuum states is elucidated. All the parameters containing information about the theory can be traced back to the characteristics of the group of residual symmetry in the light--cone gauge.

hep-th↗
arXiv1995

Conformal p-branes as a Source of Structure in Spacetime

We discuss a model of a conformal p-brane interacting with the world volume metric and connection. The purpose of the model is to suggest a mechanism by which gravity coupled to p-branes leads to the formation of structure rather than homogeneity in spacetime. Furthermore, we show that the formation of structure is accompanied by the appearance of a multivalued cosmological constant, i.e., one which may take on different values in different domains, or cells, of spacetime. The above results apply to a broad class of non linear gravitational lagrangians as long as metric and connection on the p-brane manifold are treated as independent variables.

hep-th↗
arXiv1993

Kac-Moody structure of chiral gravity in the light-cone gauge

We study the residual symmetry $SL(2,R)\otimes U(1)$ of the chiral gravity in the light-cone gauge. Quantum gravitational effects renormalize the Kac-Moody central charge and introduce, through the Lorentz anomaly, an arbitrary parameter. Due to the presence of this free parameter the Kac-Moody central charge has no forbidden range of values, and the strong gravity regime is open to investigations.

hep-th↗
arXiv1993

Gauge Theory of the String Geodesic Field

A relativistic string is usually represented by the Nambu-Goto action in terms of the extremal area of a 2-dimensional timelike submanifold of Minkowski space. Alternatively, a family of classical solutions of the string equation of motion can be globally described in terms of the associated geodesic field. In this paper we propose a new gauge theory for the geodesic field of closed and open strings. Our approach solves the technical and conceptual problems affecting previous attempts to describe strings in terms of local field variables. The connection between the geodesic field, the string current and the Kalb-Ramond gauge potential is discussed and clarified. A non-abelian generalization and the generally covariant form of the model are also discussed.

hep-th↗
arXiv1992

General treatment of anomalies in (1,0) and (1,1) two-dimensional super-gravity

In this paper we discuss the interplay among (~super-~)coordinate, Weyl and ł anomaly both in chiral and non-chiral super-gravity represented by $(1,0)$ and $(1,1)$ two-dimensional models. It is shown that for this purpose two regularization dependent parameters are needed in the effective action. We discuss in {\it full generality} the regularization ambiguities of the induced effective action and recover the corresponding general form of the anomalous Ward Identities. Finally, we explain the difference between chiral and non-chiral super-gravity models in terms of the free parameters and establish relation between these two models by projecting $(1,1)$ into $(1,0)$ super-symmetry.

hep-th↗
arXiv1992

Gravitational and Schwinger model anomalies: how far can the analogy go?

We describe the most general treatment of all anomalies both for chiral and massless Dirac fermions, in two-dimensional gravity. It is shown that for this purpose two regularization dependent parameters are present in the effective action. Analogy to the \sc\ model is displayed corresponding to a specific choice of the second parameter, thus showing that the gravitational model contains \a\ relations having no analogy in the \sc\ model.

hep-th↗
arXiv1992

Membrane Pregeometry and the Vanishing of the Cosmological Constant

We suggest a model of induced gravity in which the fundamental object is a relativistic {\it membrane} minimally coupled to a background metric and to an external three index gauge potential. We compute the low energy limit of the two-loop effective action as a power expansion in the surface tension. A generalized bootstrap hypothesis is made in order to identify the physical metric and gauge field with the lowest order terms in the expansion of the vacuum average of the composite operators conjugate to the background fields. We find that the large distance behaviour of these classical fields is described by the Einstein action with a cosmological term plus a Maxwell type action for the gauge potential. The Maxwell term enables us to apply the Hawking-Baum argument to show that the physical cosmological constant is ``~probably~'' zero.

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