Papers by Branislav Sazdovic
arXiv (Cornell University), Jun 1, 2021
In this paper we considered the bosonic string action in the presence of metric G µν , Kalb-Ramon... more In this paper we considered the bosonic string action in the presence of metric G µν , Kalb-Ramond field B µν and dilaton field Φ. The quantum conformal invariance is achieved if all three one-loop β-functions are zero. But, β Φ , β-function related to the dilaton field, can also be equal to some nonzero constant c, which is actually the central charge of Virasoro algebra. The anomaly contained in the Schwinger term of Virasoro algebra is canceled by adding Liouville term to the sigma model action and quantum conformal invariance is restored. The space-time action, which Euler-Lagrange equations of motion are quantum conformal invariance conditions with nonzero β Φ , is Einstein-Hilbert action with some matter and cosmological constant. The cosmological constant is obtained within landscape framework as linear function of the central charge of Virasoro algebra.
Gauge symmetries change the number of Dp-brane dimensions
It is known that the presence of antisymmetric background field $B_{\mu\nu}$ leads to noncommutat... more It is known that the presence of antisymmetric background field $B_{\mu\nu}$ leads to noncommutativity of Dp-brane manifold. Addition of the linear dilaton field in the form $\Phi(x)=\Phi_0+a_\mu x^\mu$, causes the appearance of the commutative Dp-brane coordinate $x=a_\mu x^\mu$. In the present article we show that for some particular choices of the background fields, $a^2\equiv G^{\mu\nu}a_\mu a_\nu=0$ and $\tilde a^2\equiv \ [ (G-4BG^{-1}B)^{-1} ]^{\mu\nu}a_\mu a_\nu=0$, the local gauge symmetries appear in the theory. They turn some Neuman boundary conditions into the Dirichlet ones, and consequently decrease the number of the Dp-brane dimensions. The physical Dp-brane is just the gauge invariant part of the initial, naive brane. The noncommutativity parameter has standard form in the physical Dp-brane. It is proportional to the induced antisymmetric field with indices raised by the open and closed string metrics induced in the gauge invariant subspace
Closed string noncommutativity in the weakly curved background
Journal of High Energy Physics, 2021
We consider the symmetries of a closed bosonic string, starting with the general coordinate trans... more We consider the symmetries of a closed bosonic string, starting with the general coordinate transformations. Their generator takes vector components ξμ as its parameter and its Poisson bracket algebra gives rise to the Lie bracket of its parameters. We are going to extend this generator in order for it to be invariant upon self T-duality, i.e. T-duality realized in the same phase space. The new generator is a function of a 2D double symmetry parameter Λ, that is a direct sum of vector components ξμ, and 1-form components λμ. The Poisson bracket algebra of a new generator produces the Courant bracket in a same way that the algebra of the general coordinate transformations produces Lie bracket. In that sense, the Courant bracket is T-dual invariant extension of the Lie bracket. When the Kalb-Ramond field is introduced to the model, the generator governing both general coordinate and local gauge symmetries is constructed. It is no longer self T-dual and its algebra gives rise to the B-...
In this article we offer the new interpretation of T-dualization procedure of type IIB superstrin... more In this article we offer the new interpretation of T-dualization procedure of type IIB superstring theory in double space framework. We use the ghost free action of type IIB superstring in pure spinor formulation in approximation of constant background fields up to the quadratic terms. T-dualization along any subset of the initial coordinates, $x^a$, is equivalent to the permutation of this subset with subset of the corresponding T-dual coordinates, $y_a$, in double space coordinate $Z^M=(x^\mu,y_\mu)$. Demanding that the T-dual transformation law after exchange $x^a\leftrightarrow y_a$ has the same form as initial one, we obtain the T-dual NS-NS and NS-R background fields. The T-dual R-R field strength is determined up to one arbitrary constant under some assumptions.
We look at the equivalence of the massive Thirring and sine-Gordon models. Previously, this equiv... more We look at the equivalence of the massive Thirring and sine-Gordon models. Previously, this equivalence was derived perturbatively in mass (though to all orders). Our calculation goes beyond that and uncovers an underlying conformal symmetry.
We show equivalence between the massive Thirring model and the sine-Gordon theory by gauge fixing... more We show equivalence between the massive Thirring model and the sine-Gordon theory by gauge fixing a wider gauge invariant theory in two different ways. The exact derivation of the equivalence hinges on the existence of an underlying conformal symmetry. Previous derivations were all perturbative in mass (althought to all orders).
Nuclear Physics B, 1985
N = 2, 4 Yang-Mills theories with soft breaking of an extended supersymmetry by mass terms are co... more N = 2, 4 Yang-Mills theories with soft breaking of an extended supersymmetry by mass terms are considered. It is proved that for N = 4 there are no ultraviolet divergences in the mass renormalization constants to all orders of perturbation theory. For N = 2 our two-loop calculations show that the charge and mass renormalization constants contain only one-loop divergences and are the same in this order. It is shown by direct calculation that mass terms can acquire finite quantum corrections starting from the two-loop approximation. The renormalization scheme dependence of N = 4 renormalization group functions is investigated. We have found that unlike renormalization schemes with minimal subtractions of divergences other renormalization schemes give a nonzero /3-function. At nonzero masses the/~-function in MOM schemes is not zero even at the one-loop level. In the massless case ,8 g 0 beginning from the two-loop approximation.
Modern Physics Letters A, 1997
We discuss a canonical formalism method for constructing actions describing propagation of W-stri... more We discuss a canonical formalism method for constructing actions describing propagation of W-strings on curved backgrounds. The method is based on the construction of a representation of the W-algebra in terms of currents made from the string coordinates and the canonically conjugate momenta. We construct such a representation for a W3-string propagating in the background metric with one flat direction by using a simple ansatz for the W-generators where each generator is a polynomial of the canonical currents and the vierbeins. In the case of a general background, we show that the simple polynomial ansatz fails, and terms containing the vierbein derivatives must be added.
The European Physical Journal C - Particles and Fields, 2003
Using the canonical method developed for anomalous theories, we present the independent rederivat... more Using the canonical method developed for anomalous theories, we present the independent rederivation of the quantum relationship between the massive Thirring and the sine-Gordon models. The same method offers the possibility to obtain the Mandelstam soliton operators as a solution of Poisson brackets "equation" for the fermionic fields. We checked the anticommutation and basic Poisson brackets relations for these composite operators. The transition from the Hamiltonian to the corresponding Lagrangian variables produces the known Mandelstam's result.
The European Physical Journal C, 2012
We investigate the open string propagation in the weakly curved background with the Kalb-Ramond f... more We investigate the open string propagation in the weakly curved background with the Kalb-Ramond field containing an infinitesimal part, linear in coordinate. Solving the Neumann boundary conditions, we find the expression for the space-time coordinates in terms of the effective ones. So, the initial theory reduces to the effective one. This effective theory is defined on the non-geometric doubled space (q µ , qµ ), where q µ is the effective coordinate and qµ is its T-dual. The effective metric depends on the coordinate q µ and there exists non-trivial effective Kalb-Ramond field which depends on the T-dual coordinate qµ . The fact that qµ is Ω-odd leads to the nonvanishing effective Kalb-Ramond field.
Journal of Physics: Conference Series, 2017
We consider a string moving in a weakly curved background, composed of a constant metric and a li... more We consider a string moving in a weakly curved background, composed of a constant metric and a linearly coordinate dependent Kalb-Ramond field with an infinitesimal strength. We discuss the T-dualization procedure which we developed for a closed bosonic string moving in a weakly curved background. The procedure is a generalization of a Buscher T-dualization procedure and enables the T-dualization of the nonisometry directions. The same procedure is used to investigate the T-duals of an open bosonic string as well. The generalized T-dualizations give insight to the connection between the geometrical properties of the T-dual spaces.
The European Physical Journal C, 2017
The role of double space is essential in the new interpretation of T-duality and consequently in ... more The role of double space is essential in the new interpretation of T-duality and consequently in an attempt to construct M-theory. The case of the open string is missing in such an approach because until now there has been no appropriate formulation of open string T-duality. In the previous paper (Sazdović, From geometry to non-geometry via T-duality, arXiv:1606.01938, 2017), we showed how to introduce vector gauge fields A N a and A D i at the end-points of an open string in order to enable open string invariance under local gauge transformations of the Kalb-Ramond field and its T-dual "restricted general coordinate transformations". We demonstrated that gauge fields A N a and A D i are T-dual to each other. In the present article we prove that all above results can be interpreted as coordinate permutations in double space.
From Neuman to Dirichlet boundary conditions
AIP Conference Proceedings, 2007
The Dirichlet boundary conditions for the end-point of the open string define Dp-brane. It is par... more The Dirichlet boundary conditions for the end-point of the open string define Dp-brane. It is parameterized by the rest of coordinates, with Neuman boundary conditions. The relations between background fields can produce the local gauge symmetries of the world-sheet action. After gauge fixing, some Neuman boundary conditions turn into the Dirichlet ones, decreasing the number of Dp-brane dimensions. The physical Dp-brane is gauge invariant part of the initial one. The gauge invariant coordinates are expressed as linear combinations of the effective coordinates and momenta. This fact explains the origin of non-commutativity and the existence of commutative Dp-brane coordinates.
2D Induced Gravity from a WZNW System
Recent Developments in Theoretical and Experimental General Relativity Gravitation and Relativistic Field Theories, 1999
We introduce a consistent gauge extension of the SL(2, R) WZNW system, defined by a difference of... more We introduce a consistent gauge extension of the SL(2, R) WZNW system, defined by a difference of two simple WZNW actions. By integrating out some dynamical variables in the functional integral, we show that the resulting effective theory coincides with the induced gravity in 2D. General solutions of both theories are found and related to each other.
On the possibility of dynamical mass generation in axial electrodynamics
Journal of Physics G: Nuclear Physics, 1982
ABSTRACT
An analysis of the Schwinger-Dyson equation for the finite electron propagator
Journal of Physics G: Nuclear Physics, 1982
ABSTRACT
Complete T-Dualization of a String in a Weakly Curved Background
Springer Proceedings in Mathematics & Statistics, 2014
We apply the generalized Buscher procedure, to a subset of the initial coordinates of the bosonic... more We apply the generalized Buscher procedure, to a subset of the initial coordinates of the bosonic string moving in the weakly curved background, composed of a constant metric and a linearly coordinate dependent Kalb-Ramond field with the infinitesimal strength. In this way we obtain the partially T-dualized action. Applying the procedure to the rest of the original coordinates we obtain the totally T-dualized action. This derivation allows the investigation of the relations between the Poisson structures of the original, the partially T-dualized and the totally T-dualized theory.
Uploads
Papers by Branislav Sazdovic