arXiv subjects
Publications and source records attributed to Emil Nissimov.
We propose a new class of p-brane models describing intrinsically lightlike branes in any world-volume dimensions. Properties of the dynamics of these lightlike p-branes in various gravitational backgrounds of interest in the context of braneworlds are briefly described. Codimenion two (and more) lightlike braneworlds perform in their ground states non-trivial motions in the extra dimensions in sharp contrast to standard (Nambu-Goto) braneworlds.
We consider self-consistent coupling of the recently introduced new class of Weyl-conformally invariant lightlike branes (WILL-branes) to D=4 Einstein-Maxwell system plus a D=4 three-index antisymmetric tensor gauge field. We find static spherically-symmetric solutions where the space-time consists of two regions with different black-hole-type geometries and different values for a dynamically generated cosmological constant, separated by the WILL-brane which ``straddles'' their common event horizon. Furthermore, the WILL-brane produces a potential ``well'' around itself acting as a trap for test particles falling towards the horizon.
Preliminary version of a contribution to the "Quantum Field Theory. Non-Perturbative QFT" topical area of "Modern Encyclopedia of Mathematical Physics" (SELECTA), eds. Aref'eva I, and Sternheimer D, Springer (2007). Consists of two parts - "main article" (Large N Expansion. Vector Models) and a "brief article" (BPHZL Renormalization).
We study self-consistent D=4 gravity-matter systems coupled to a new class of Weyl-conformally invariant lightlike branes (WILL}-branes). The latter serve as material and charged source for gravity and electromagnetism. Further, due to the natural coupling to a 3-index antisymmetric tensor gauge field, the WILL-brane dynamically produces a space-varying bulk cosmological constant. We find static spherically-symmetric solutions where the space-time consists of two regions with black-hole-type geometries separated by the WILL-brane which "straddles" their common event horizon and, therefore, provides an explicit dynamical realization of the "membrane paradigm" in black hole physics. Finally, by matching via WILL-brane of internal Schwarzschild-de-Sitter with external Reissner-Nordstrom-de-Sitter (or external Schwarzschild-de-Sitter)geometries we discover the emergence of a potential "well" for infalling test particles in the vicinity of the WILL-brane (the common horizon) with a minimum on the brane itself.
We discuss a new class of brane models (extending both p-brane and Dp-brane cases) where the brane tension appears as an additional dynamical degree of freedom instead of being put in by hand as an ad hoc dimensionfull scale. Consistency of dynamics naturally involves the appearence of additional higher-rank antisymmetric tensor gauge fields on the world-volume which can couple to charged lower-dimensional branes living on the original Dp-brane world-volume. The dynamical tension has the physical meaning of electric-type field strength of the additional higher-rank world-volume gauge fields. It obeys Maxwell (or Yang-Mills) equations of motion (in the string case p=1) or their higher-rank gauge theory analogues (in the Dp-brane case). This in particular triggers a simple classical mechanism of ("color") charge confinement.
We propose a new class of p-brane theories which are Weyl-conformally invariant for any p. For any odd world-volume dimension the latter describe intrinsically light-like branes, hence the name WILL-branes (Weyl-Invariant Light-Like branes). Next we discuss the dynamics of WILL-membranes (i.e., for p=2) both as test branes in various external physically relevant D=4 gravitational backgrounds, as well as within the framework of a coupled D=4 Einstein-Maxwell-WILL-membrane system. In all cases we find that the WILL-membrane materializes the event horizon of the corresponding black hole solutions, thus providing an explicit dynamical realization of the membrane paradigm in black hole physics.
We consider a novel class of Weyl-conformally invariant p-brane theories which describe intrinsically light-like branes for any odd world-volume dimension, hence the acronym WILL-branes (Weyl-Invariant Light-Like branes). We discuss in some detail the properties of WILL-brane dynamics which significantly differs from ordinary Nambu-Goto brane dynamics. We provide explicit solutions of WILL-membrane (i.e., p=2) equations of motion in arbitrary D=4 spherically symmetric static gravitational backgrounds, as well as in product spaces of interest in Kaluza-Klein context. In the first case we find that the WILL-membrane materializes the event horizon of the corresponding black hole solutions, thus providing an explicit dynamical realization of the membrane paradigm in black hole physics. In the second "Kaluza-Klein" context we find solutions describing WILL-branes wrapped around the internal (compact) dimensions and moving as a whole with the speed of light in the non-compact (space-time) dimensions.
We discuss in some detail the properties of a novel class of Weyl-conformally invariant p-brane theories which describe intrinsically light-like branes for any odd world-volume dimension and whose dynamics significantly differs from that of the ordinary (conformally non-invariant) Nambu-Goto p-branes. We present explicit solutions of the WILL-brane (Weyl-Invariant Light-Like brane) equations of motion in various gravitational backgrounds of physical relevance exhibiting the following new phenomena: (i) In spherically symmetric static backgrounds the WILL-brane automatically positions itself on (materializes) the event horizon of the corresponding black hole solutions, thus providing an explicit dynamical realization of the membrane paradigm in black hole physics; (ii) In product spaces (of interest in Kaluza-Klein context) the WILL-brane wrappes non-trivially around the compact (internal) dimensions and moves as a whole with the speed of light in the non-compact (space-time) dimensions.
The use in the action integral of a volume element of the form $Φd^{D}x$ where $Φ$ is a metric independent measure can give new interesting results in all types of known generally coordinate invariant theories: (1) 4-D theories of gravity plus matter fields; (2) Reparametrization invariant theories of extended objects; (3) Higher dimensional theories. In the case (1), a large number of new effects appears: under normal particle physics conditions (primordial) fermions split into three families; when matter is highly diluted, neutrinos increase their mass and can contribute both to dark energy and to dark matter. In the case (2), it leads to dynamically induced tension; to string models of non abelian confinement; to the possibility of new Weyl-conformally invariant light-like branes which dynamically adjust themselves to sit at black hole horizons; in the context of higher dimensional theories it can provide examples of massless 4-D particles with nontrivial Kaluza Klein quantum numbers. In the case (3), i.e. in brane and Kaluza Klein scenarios, the use of a metric independent measure makes it possible to construct naturally models where only the extra dimensions get curved and the 4-D remain flat.
We discuss a new class of string and p-brane models where the string/brane tension appears as an additional dynamical degree of freedom instead of being introduced by hand as an ad hoc dimensionfull scale. The latter property turns out to have a significant impact on the string/brane dynamics. The dynamical tension obeys Maxwell (or Yang-Mills) equations of motion (in the string case) or their rank p gauge theory analogues (in the p-brane case), which in particular triggers a simple classical mechanism of ("color") charge confinement.
We study in some detail the properties of a previously proposed new class of string and brane models whose world-sheet (world-volume) actions are built with a modified reparametrization-invariant measure of integration and which do not contain any ad hoc dimensionfull parameters. The ratio of the new and the standard Riemannian integration measure densities plays the role of a dynamically generated string/brane tension. The latter is identified as (the magnitude of) an effective (non-Abelian) electric field-strength on the world-sheet/world-volume obeying the standard Gauss-law constraint. As a result a simple classical mechanism for confinement via strings is proposed.
The recently proposed supersymmetric extensions of reduced Kadomtsev-Petviashvili (KP) integrable hierarchies in $N =1,2$ superspace are shown to contain in the purely bosonic limit new types of ordinary non-supersymmetric integrable systems. The latter are coupled systems of several multi-component non-linear Schr{ö}dinger-like hierarchies whose basic nonlinear evolution equations contain additional quintic and higher-derivative nonlinear terms. Also, we obtain the N=2 supersymmetric extension of Toda chain model as Darboux-B{ä}cklund orbit of the simplest reduced N=2 super-KP hierarchy and find its explicit solution.
We study additional non-isospectral symmetries of constrained (reduced) N=2 supersymmetric KP hierarchies of integrable ``soliton''-like evolution equations. These symmetries are shown to form an infinite-dimensional non-Abelian superloop superalgebra. Furthermore we study the general Darboux-Backlund (DB) transformations (including adjoint-DB and binary DB) of N=2 super- KP hierarchies preserving (most of) the additional symmetries. Also we derive the explicit form of the general DB (N=2 ``super- soliton''-like) solutions in the form of generalized Wronskian-like super-determinants.
This paper is devoted to the systematic study of additional (non- isospectral) symmetries of constrained (reduced) supersymmetric integrable hierarchies of KP type- the so called SKP_(R;M_B,M_F) models. The latter are supersymmetric extensions of ordinary constrained KP hierarchies which contain as special cases basic integrable systems such as (m)KdV, AKNS, Fordy-Kulish, Yajima- Oikawa etc.. As a first main result it is shown that any SKP_(R;M_B,M_F) hierarchy possesses two different mutually (anti-)commuting types of superloop superalgebra additional symmetries corresponding to the positive-grade and negative-grade parts of certain superloop superalgebras. The second main result is the systematic construction of the full algebra of additional Virasoro symmetries of SKP_(R;M_B,M_F) hierarchies, which requires non- trivial modifications of the Virasoro flows known from the general case of unconstrained Manin-Radul super-KP hierarchies (the latter flows do not define symmetries for constrained SKP_(R;M_B,M_F) hierarchies). As a third main result we provide systematic construction of the supersymmetric analogues of multi-component (matrix) KP hierarchies and show that the latter contain among others the supersymmetric version of Davey-Stewartson system. Finally, we present an explicit derivation of the general Darboux- Bäcklund solutions for the SKP_(R;M_B,M_F) super-tau functions (supersymmetric ``soliton''-like solutions) which preserve the additional (non-isospectral) symmetries.
This work consist of two interrelated parts. First, we derive massive gauge-invariant generalizations of geometric actions on coadjoint orbits of arbitrary (infinite-dimensional) groups $G$ with central extensions, with gauge group $H$ being certain (infinite-dimensional) subgroup of $G$. We show that there exist generalized ``zero-curvature'' representation of the pertinent equations of motion on the coadjoint orbit. Second, in the special case of $G$ being Kac-Moody group the equations of motion of the underlying gauged WZNW geometric action are identified as additional-symmetry flows of generalized Drinfeld-Sokolov integrable hierarchies based on the loop algebra ${\hat \cG}$. For ${\hat \cG} = {\hat {SL}}(M+R)$ the latter hiearchies are equivalent to a class of constrained (reduced) KP hierarchies called ${\sl cKP}_{R,M}$, which contain as special cases a series of well-known integrable systems (mKdV, AKNS, Fordy-Kulish, Yajima-Oikawa etc.). We describe in some detail the loop algebras of additional (non-isospectral) symmetries of ${\sl cKP}_{R,M}$ hierarchies. Apart from gauged WZNW models, certain higher-dimensional nonlinear systems such as Davey-Stewartson and $N$-wave resonant systems are also identified as additional symmetry flows of ${\sl cKP}_{R,M}$ hierarchies. Along the way we exhibit explicitly the interrelation between the Sato pseudo-differential operator formulation and the algebraic (generalized) Drinfeld-Sokolov formulation of ${\sl cKP}_{R,M}$ hierarchies. Also we present the explicit derivation of the general Darboux-Bäcklund solutions of ${\sl cKP}_{R,M}$ preserving their additional (non-isospectral) symmetries, which for R=1 contain among themselves solutions to the gauged $SL(M+1)/U(1)\times SL(M)$ WZNW field equations.
We show that any multi-component matrix KP hierarchy is equivalent to the standard one-component (scalar) KP hierarchy endowed with a special infinite set of abelian additional symmetries, generated by squared eigenfunction potentials. This allows to employ a special version of the familiar Darboux-B"acklund transformation techniques within the ordinary scalar KP hierarchy in the Sato formulation for a systematic derivation of explicit multiple-Wronskian tau-function solutions of all multi-component matrix KP hierarchies.
We describe new theories of composite vector and tensor (p-form) gauge fields made out of zero-dimensional constituent scalar fields (``primitives''). The local gauge symmetry is replaced by an infinite-dimensional global Noether symmetry -- the group of volume-preserving (symplectic) diffeomorphisms of the target space of the scalar primitives. We find additional non-Maxwell and non-Kalb-Ramond solutions describing topologically massive tensor gauge field configurations in odd space-time dimensions. Generalization to the supersymmetric case is also sketched.
This is mainly a brief review of some key achievements in a `hot'' area of theoretical and mathematical physics. The principal aim is to outline the basic structures underlying {\em integrable} quantum field theory models with {\em infinite-dimensional} symmetry groups which display a radically new type of {\em quantum group} symmetries. Certain particular aspects are elaborated upon with some detail: integrable systems of Kadomtsev-Petviashvili type and their reductions appearing in matrix models of strings; Hamiltonian approach to Lie-Poisson symmetries; quantum field theory approach to two-dimensional relativistic integrable models with dynamically broken conformal invariance. All field-theoretic models in question are of primary relevance to diverse branches of physics ranging from nonlinear hydrodynamics to string theory of fundamental particle interactions at ultra-high energies.