Super p-branes

It is shown that the extension of the spacetime supersymmetric Green-Schwarz covariant action p-dimensional extended objects (p-branes) is possible if and only if the on-shell p-dimensional Bose and Fermi degrees of freedom are equal. This is further evidence for world-tube supersymmetry in these models. All the p-branes models are related to superstring actions in d=3, 4, 6 or 10 dimensions by double dimensional reduction (which we generalise to reduction on arbitrary compact spaces), and we also show how they may be considered as topological defects of supergravity theories.     

Stainless super p-branes

The elementary and solitonic supersymmetric p-brane solutions to supergravity theories form families related by dimensional reduction, each headed by a maximal (‘stainless’) member that cannot be isotropically dimensionally oxidized into higher dimensions. We find several new families, headed by stainless solutions in various dimensions D ⩽ 9. In some cases, these occur with dimensions (D, p) that coincide with those of descendants of known families, but since the new solutions are stainless, they are necessarily distinct. The new stainless supersymmetric solutions include a 6-brane and a 5-brane in D = 9, a string in D = 5, and particles in all dimensions 5 ⩽ D ⩽ 9.     

Super-weyl-invariant spinning p-branes

We discuss possible world-volume supersymmetrizations of the Weyl-invariant first-order action for p-dimensional extended objects (p-branes). In particular we present a spinning membrane (p=2), and a super-Weyl-invariant three-brane.     

Born-Infeld Kinematics

We encode dynamical symmetries of Born-Infeld theory in a geometry on the tangent bundle of generally curved spacetime manifolds. The resulting covariant formulation of a maximal acceleration extension of special and general relativity is put to use in the discussion of particular point particle dynamics and the transition to a first quantized theory.     

Topological aspect of Chern--Simons p-branes

By generalizing the topological current of Abelian Chern--Simons (CS) vortices, we present a topological tensor current of CS p-branes based on the \phi -mapping topological current theory. It is revealed that CS p-branes are located at the isolated zeros of the vector field \phi(x), and the topological structure of CS p-branes is characterized by the winding number of the \phi-mappings. Furthermore, the Nambu--Goto action and the equation of motion for multi CS p-branes are obtained.     

Topological structure of Gauss-Bonnet-Chern theorem and -branes

By making use of the φ-mapping topological current theory, this paper shows that the Gauss-Bonnet-Chern density (the Euler-Poincaré characteristic χ(M) density) can be expressed in terms of a smooth vector field φ and take the form of δ(φ), which means that only the zeros of φ contribute to χ(M). This is the elementary fact of the Hopf theorem. Furthermore, it presents that a new topological tensor current of -branes can be derived from the Gauss-Bonnet-Chern density. Using this topological current, it obtains the generalized Nambu action for multi -branes.     

Born-Infeld axion-dilaton electrodynamics and electromagnetic confinement

A generalization of Born-Infeld non-linear vacuum electrodynamics involving axion and dilaton fields is constructed with couplings dictated by electromagnetic duality and SL(2,R) symmetries in the weak field limit. Besides the Newtonian gravitational constant the model contains a single fundamental coupling parameter b₀. In the absence of axion and dilaton interactions it reduces in the limit b₀?∞ to Maxwell?s linear vacuum theory while for finite b₀ it reduces to the original Born-Infeld model. The spherically symmetric static sector of the theory is explored in a flat background spacetime in the Jordan frame where numerical evidence suggests the existence of axion-dilaton bound states possessing confined electric flux.     

Noncommutative versions of Born-Infeld theory

A new generalization of nonlinear Born-Infeld electrodynamics is proposed. It is inspired by the noncommutative geometry and a new interpretation of gauge theories. The variational principle introduced here leads to quite complicated nonlinear equations, which can be solved numerically in certain cases. The spherically symmetric ansatz is analyzed, and static finite-energy solutions are obtained via numerical integration. Then a pure Higgs sector Lagrangian is introduced by analogy with the non-Abelian Born-Infeld generalization. A spherically symmetric configuration and a time-dependent homogeneous field are investigated and qualitative behavior of solutions are discussed.     

Heterotic p-branes from massive sigma models

We explicitly construct massive (0,4) supersymmetric ADHM sigma models which have heterotic p-brane solitons as their conformal fixed points. These yield the familiar gauge 5-brane and a new 1-brane solution which preserve half and a quarter of the space-time supersymmetry, respectively. We also discuss an analogous construction for the type 11 NS-NS p-branes using (4,4) supersymmetric models.     

Requiem for the Born-Infeld electron

It is shown that the supposed existence of a particlelike solution in the Born-Infeld electrodynamics is due to an error, and comments are made on the significance of this result for unitary and unified theories.     

Letter: Anisotropic Born-Infeld Cosmologies

Anisotropic cosmological spacetimes are constructed from spherically symmetric solutions to Einstein's equations coupled to nonlinear electrodynamics and a positive cosmological constant. This is accomplished by finding solutions in which the roles of r and t are interchanged for all r > 0 (i.e. r becomes timelike and t becomes spacelike). Constant time hypersurfaces have topology R× S ² and in all the spacetimes considered the radius of the two sphere vanishes as t goes to zero. The scale factor of the other dimension diverges as t goes to zero in some solutions and vanishes (or goes to a constant) in other solutions. At late times local observers would see the universe to be homogeneous and isotropic.     

World-volume locally supersymmetric Born-Infeld actions

We derive manifestly locally supersymmetric extensions of the Born-Infeld action with p=2. The construction is based on a first order bosonic action for Dp-branes with a generalized Weyl invariance.     

Testing Born-Infeld electrodynamics in waveguides

Waveguides can be employed to test nonlinear effects in electrodynamics. We solve Born-Infeld equations for TE waves in a rectangular waveguide. We show that the energy velocity acquires a dependence on the amplitude, and harmonic components appear as a consequence of the nonlinear behavior.     

Intersecting Electric and Magnetic p-branes: Spherically Symmetric Solutions

We consider a D-dimensional self-gravitatingspherically symmetric configuration of a generalizedelectro-magnetic n-form F and a dilatonic scalar field,admitting an interpretation in terms of intersecting p-branes. For theories with additional(internal) times, selection rules are obtained, whichobstruct the existence of p-branes in certain subspaces.General static solutions are obtained under a specific restriction on the model parameters, whichcorresponds to certain orthogonality relations in thetarget-space of effective fields. More special familiesof solutions (with equal charges for some of the F-field components) are found with weakenedrestrictions on the input parameters. Black-holesolutions are determined, and it is shown that in theextreme limit the Hawking temperature may tend to zero, a finite value, or infinity, depending on thep-brane intersection dimension. A kind of no-hairtheorem is obtained, claiming that black holes cannotcoexist with a quasiscalar component of theF-field.