scholarly journals Classical and quantum $$(2+1)$$-dimensional spatially homogeneous string cosmology

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
F. Naderi ◽  
A. Rezaei-Aghdam
Keyword(s):  
Effective Action ◽  
Central Charge ◽  
Dimensional Space ◽  
String Cosmology ◽  
Quantum Level ◽  
Leading Order ◽  
Semiclassical Analysis ◽  
Conditional Symmetry ◽  
Spatially Homogeneous

AbstractWe introduce three families of classical and quantum solutions to the leading order of string effective action on spatially homogeneous $$(2+1)$$ ( 2 + 1 ) -dimensional space-times with the sources given by the contributions of dilaton, antisymmetric gauge B-field, and central charge deficit term $$\varLambda $$ Λ . At the quantum level, solutions of Wheeler–DeWitt equations have been enriched by considering the quantum versions of the classical conditional symmetry equations. Concerning the possible applications of the obtained solutions, the semiclassical analysis of Bohm’s mechanics has been performed to demonstrate the possibility of avoiding the classical singularities at the quantum level.

scholarly journals COMPUTATION OF THE CENTRAL CHARGE FOR THE LEADING ORDER OF THE N = 2 SUPER-YANG–MILLS EFFECTIVE ACTION

1999 ◽  
Vol 14 (40) ◽  
pp. 2789-2795 ◽  
Author(s):  
SYLVAIN WOLF
Keyword(s):  
Quantum Theory ◽  
Effective Action ◽  
Essential Role ◽  
Central Charge ◽  
Low Energy ◽  
Leading Order ◽  
Direct Computation ◽  
Yang Mills ◽  
Bps States ◽  
Super Yang Mills Theory

The central charge in the N=2 super-Yang–Mills theory plays an essential role in the work of Seiberg and Witten as it gives the mass spectrum of the BPS states of the quantum theory. Our aim in this letter is to present a direct computation of this central charge for the leading order (in a momentum expansion) of the effective action. We will consider the N=2 super-Yang–Mills theory with gauge group SU(2). The leading order of the effective action is given by the same holomorphic function ℱ appearing in the low energy U(1) effective action.

scholarly journals About renormalized effective action for the Yang-Mills theory in four-dimensional space-time

2018 ◽  
Vol 191 ◽  
pp. 06001
Author(s):  
A.V. Ivanov
Keyword(s):  
Infinite Series ◽  
Effective Action ◽  
Dimensional Space ◽  
Space Time ◽  
Coupling Constant ◽  
Asymptotic Approach ◽  
Yang Mills ◽  
Dimensional Space Time ◽  
Bare Coupling Constant ◽  
Renormalization Theory

This work is related to the asymptotic approach in the renormalization theory and its problems. As the main example, the Yang-Mills theory in four-dimensional space-time is considered. It has been shown earlier [16] that using the asymptotic of the bare coupling constant one can find an expression for the renormalized effective action, however, this formula has problems (divergence ln " and infinite series). This work shows the relation of these values and provides an answer for the renormalized effective action.

scholarly journals ON GAUGE DYNAMICS AND SUSY BREAKING IN ORIENTIWORLD

2002 ◽  
Vol 17 (27) ◽  
pp. 3875-3895
Author(s):  
ZURAB KAKUSHADZE
Keyword(s):  
Crucial Role ◽  
Dimensional Space ◽  
Susy Breaking ◽  
Brane World ◽  
The Other ◽  
Quantum Level ◽  
Rich Variety ◽  
World Volume ◽  
The Standard Model ◽  
Dimensional Gravity

In the orientiworld framework the Standard Model fields are localized on D3-branes sitting on top of an orientifold three-plane. The transverse six-dimensional space is a noncompact orbifold (or a more general conifold). The four-dimensional gravity on D3-branes is reproduced due to the four-dimensional Einstein–Hilbert term induced at the quantum level. The orientifold three-plane plays a crucial role, in particular, without it the D3-brane world-volume theories would be conformal due to the tadpole cancellation. We study nonperturbative gauge dynamics in various [Formula: see text] supersymmetric orientiworld models based on the Z3 as well as Z5 and Z7 orbifold groups. Our discussions illustrate that there is a rich variety of supersymmetry preserving dynamics in some of these models. On the other hand, we also find some models with dynamical supersymmetry breaking.

scholarly journals A bulk localized state and new holographic renormalization group flow in 3D spin-3 gravity

2018 ◽  
Vol 33 (12) ◽  
pp. 1850061 ◽  
Author(s):  
Ryuichi Nakayama ◽  
Tomotaka Suzuki
Keyword(s):  
Renormalization Group ◽  
Scalar Field ◽  
Central Charge ◽  
Dimensional Space ◽  
Space Time ◽  
Internal Space ◽  
Conformal Weight ◽  
Weight Changes ◽  
Localized State ◽  
Bulk Space

We construct a localized state of a scalar field in 3D spin-3 gravity. 3D spin-3 gravity is thought to be holographically dual to [Formula: see text]-extended CFT on a boundary at infinity. It is known that while [Formula: see text] algebra is a nonlinear algebra, in the limit of large central charge [Formula: see text] a linear finite-dimensional subalgebra generated by [Formula: see text] [Formula: see text] and [Formula: see text] [Formula: see text] is singled out. The localized state is constructed in terms of these generators. To write down an equation of motion for a scalar field which is satisfied by this localized state, it is necessary to introduce new variables for an internal space [Formula: see text], [Formula: see text], [Formula: see text], in addition to ordinary coordinates [Formula: see text] and [Formula: see text]. The higher-dimensional space, which combines the bulk space–time with the “internal space,” which is an analog of superspace in supersymmetric theory, is introduced. The “physical bulk space–time” is a 3D hypersurface with constant [Formula: see text], [Formula: see text] and [Formula: see text] embedded in this space. We will work in Poincaré coordinates of AdS space and consider [Formula: see text]-quasi-primary operators [Formula: see text] with a conformal weight [Formula: see text] in the boundary and study two and three point functions of [Formula: see text]-quasi-primary operators transformed as [Formula: see text]. Here, [Formula: see text] and [Formula: see text] are [Formula: see text] generators in the hyperbolic basis for Poincaré coordinates. It is shown that in the [Formula: see text] limit, the conformal weight changes to a new value [Formula: see text]. This may be regarded as a Renormalization Group (RG) flow. It is argued that this RG flow will be triggered by terms [Formula: see text] added to the action.

scholarly journals WZW-TODA REDUCTION USING THE CASIMIR OPERATOR

1994 ◽  
Vol 09 (05) ◽  
pp. 745-758 ◽  
Author(s):  
I. JACK ◽  
J. PANVEL
Keyword(s):  
Field Theory ◽  
Casimir Operator ◽  
Central Charge ◽  
Hamiltonian Operator ◽  
Quantum Level ◽  
Quantum Hamiltonian ◽  
Toda Field Theory

We construct a quantum Hamiltonian operator for the Wess-Zumino-Witten (WZW) model in terms of the Casimir operator. This facilitates the discussion of the reduction of the WZW model to the Toda field theory at the quantum level and provides a very straightforward derivation of the quantum central charge for the Toda field theory.

scholarly journals Marginal deformations of a class of AdS3 $$ \mathcal{N} $$ = (0, 4) holographic backgrounds

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Salomon Zacarías
Keyword(s):  
Central Charge ◽  
Dimensional Space ◽  
Marginal Deformations

Abstract We discuss marginal deformations of warped AdS3×S2 solutions preserving small $$ \mathcal{N} $$ N = (0, 4) supersymmetry in massive IIA and eleven-dimensional supergravity and obtain a whole family of new solutions. We characterise these new backgrounds by studying some observables like the quantised charges, associated Hannany-Witten brane set-ups and the holographic central charge, the latter is shown to be invariant under the deformation. The study of the preservation of supersymmetry shows that the new backgrounds support a dynamical SU(2) structure on the internal five-dimensional space.

scholarly journals A NONSINGULAR UNIVERSE IN STRING COSMOLOGY

1999 ◽  
Vol 08 (01) ◽  
pp. 43-49 ◽  
Author(s):  
A. A. AL-NOWAISER ◽  
MURAT ÖZER ◽  
M. O. TAHA
Keyword(s):  
General Relativity ◽  
Central Charge ◽  
Energy Condition ◽  
Homogeneous Solution ◽  
Low Energy ◽  
Leading Order ◽  
Tensor Fields ◽  
Strong Energy Condition ◽  
Four Dimensions ◽  
Strong Energy

We consider the low-energy effective string action in four dimensions including the leading order-α′ terms. An exact homogeneous solution is obtained. It represents a nonsingular expanding cosmological model in which the tensor fields tend to vanish as t→∞. The scale factor a(t) of the very early universe in this model has the time dependence [Formula: see text]. The violation of the strong energy condition of classical General Relativity to avoid the initial singularity requires that the central charge deficit of the theory be larger than a certain value. The significance of this solution is discussed.

scholarly journals CENTRAL CHARGES AND EFFECTIVE ACTION AT FINITE TEMPERATURE AND DENSITY

2004 ◽  
Vol 19 (03) ◽  
pp. 223-238 ◽  
Author(s):  
J. GAMBOA ◽  
J. LÓPEZ-SARRIÓN ◽  
M. LOEWE ◽  
F. MÉNDEZ
Keyword(s):  
Explicit Expression ◽  
Current Algebra ◽  
Effective Action ◽  
Finite Temperature ◽  
Gauge Theories ◽  
Central Charge ◽  
Thirring Model ◽  
Coupling Constant ◽  
Four Dimensions

The current algebra for gauge theories like QCD at finite temperature and density is studied. We start considering, the massless Thirring model at finite temperature and density, finding an explicit expression for the current algebra. The central charge only depends on the coupling constant and there are not new effects due to temperature and density. From this calculation, we argue how to compute the central charge for QCD4 and we argue why the central charge in four dimensions could be modified by finite temperature and density.

scholarly journals INHOMOGENEOUS STRING COSMOLOGY SOLUTIONS WITH REGULAR SPACE–TIME CURVATURE

1999 ◽  
Vol 14 (01) ◽  
pp. 43-49 ◽  
Author(s):  
LUIS O. PIMENTEL
Keyword(s):  
Effective Action ◽  
Analytic Solutions ◽  
Space Time ◽  
String Cosmology ◽  
Cosmological Models ◽  
Low Energy ◽  
Tree Level ◽  
Regular Space

In this work cosmological models are considered for the low energy string cosmological effective action (tree level) in the absence of dilaton potential. A two-parametric nondiagonal family of analytic solutions is found. The curvature is nonsingular, however the string coupling diverges exponentially.

scholarly journals NON-RELATIVISTIC FERMIONS, COADJOINT ORBITS OF W∞ AND STRING FIELD THEORY AT c=1

1992 ◽  
Vol 07 (33) ◽  
pp. 3129-3145 ◽  
Author(s):  
AVINASH DHAR ◽  
GAUTAM MANDAL ◽  
SPENTA R. WADIA
Keyword(s):  
Dimensional Space ◽  
Space Distribution ◽  
One Dimension ◽  
Coadjoint Orbits ◽  
Leading Order ◽  
Weak Coupling Regime ◽  
Phase Space Distribution ◽  
Dimensional Space Time ◽  
Area Preserving ◽  
Geometric Formulation

We apply the method of coadjoint orbits of W∞-algebra to the problem of non-relativistic fermions in one dimension. This leads to a geometric formulation of the quantum theory in terms of the quantum phase space distribution of the Fermi fluid. The action has an infinite series of expansion in the string coupling, which to leading order reduces to the previously discussed geometric action for the classical Fermi fluid based on the group w∞ of area-preserving diffeomorphisms. We briefly discuss the strong coupling limit of the string theory which, unlike the weak coupling regime, does not seem to admit a two-dimensional space-time picture. Our methods are equally applicable to interacting fermions in one dimension.

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