Exact Plane Wave Solutions Research Articles

Strings in strong gravitational fields.

String propagation in exact plane-wave solutions (with nonzero axion and dilaton fields) is analyzed. In these backgrounds, strings can undergo transitions from one state to another. Selection rules are derived which describe allowed and forbidden transitions of the string. It is shown that singular plane waves result in infinitely excited strings. An example is given of a solution whose singular properties are the opposite of an orbifold: it is geodesically complete, but still singular from the standpoint of string theory. Some implications of these results are discussed.

A class of exact plane wave solutions of the Maxwell–Dirac equations

Exact solutions of Maxwell–Dirac equations are investigated for which the Dirac field is of the type ψ(x)=α(p)eipλxλ. In the subclass where the mass parameter m≠0, there exists no nontrivial solution of the problem. In the subclass where the mass parameter m=0, there exist infinitely many solutions inherent with arbitrary functions. Furthermore, every solution for m=0 must have a null four-current vector field associated with it.

Exact plane-wave solutions in higher-dimensional space-time

Exact solutions representing the field of mixed plane-gravitational and plane-electromagnetic waves under the generalized harmonic condition in higher-dimensional space-time are obtained. The energy-flux density of the waves is discussed.

Plane waves in effective field theories of superstrings

Exact plane wave solutions of d = 10, N = 1 Einstein-Yang-Mills supergravity theory are presented and their possible modifications in superstring effective theories are examined. It is found that the solutions are not affected by any of the known heterotic string corrections. It is argued that plane waves satisfy the effective field equations of the heterotic string theory in all powers of the string tension parameter α′, possibly after including a totally antisymmetric torsion field and reinterpreting the constants. Similar remarks also apply for type I superstrings. Further properties of the solutions are discussed.

Killing spinors and exact plane-wave solutions of extended supergravity

Urrutia's ansatz for exact plane-wave solutions of simple supergravity is generalized to $N=2$ extended supergravity and conditions are given for the solutions to be nontrivial. Conditions are also given for the plane-wave background to be invariant under a local supersymmetry transformation generated by a Killing spinor. It is seen that even though a bosonic background can admit a spin-$\frac{3}{2}$ solution when it does not possess a Killing spinor, if it is supersymmetric it admits a more general gravitino solution. Comparison is made with the solutions of Aichelburg and Dereli.

A new class of exact pp-wave solutions in simple supergravity

A class of exact solutions of the O(1) supergravity theory is presented. It is obtained from an ansatz motivated by a previously known exact plane-wave solution together with the additional assumption that the connection forms equal their torsion-free and zero-order Grassmann part. The demonstrated solutions are nontrivial and admit a covariantly constant spinor field.

First non trivial exact solution of supergravity

An exact plane wave solution of the coupled supergravity field equations is given. It is non-trivial in the sense that it cannot be reduced to the parallel-plane wave solution of vacuum Einstein's equations by supersymmetry transformations.

Exact plane wave solutions of O(2) extended supergravity

Non gauge generated exact plane wave solutions of the O(2) extended supergravity field equations are given.

Conformal two-structure as the gravitational degrees of freedom in general relativity

In this paper, we suggest that what we shall call the conformal 2-structure may, in an appropriate coordinate system, serve to embody the two gravitational degrees of freedom of the Einstein (vacuum) field equations. The conformal 2-structure essentially gives information concerning the manner in which a family of 2-surfaces is embedded in a 3-surface. We show that, formally at least, this prescription works for the exact plane and cylindrical gravitational wave solutions, for the double-null and null-timelike characteristic initial value problems, and for the usual Cauchy spacelike initial value problem. We conclude with a preliminary consideration of a two-plus-two breakup of the field equations aimed at unifying these and other initial value problems; and a discussion of some aspirations and remaining problems of this approach.

Exact plane-wave solutions of supergravity field equations

Exact plane-wave solutions of supergravity field equations are given. These solutions generalize the parallel-plane-wave solutions of vacuum Einstein's equations; however, they are not related to them by supersymmetry transformations.

Generation of harmonics in gravitational waves

Exact plane-wave solutions of the Einstein equations which correspond to monochromatic superpositions of plane waves in the linearized theory are studied. The metric involves solutions of the Mathieu equation, and it is shown that it can be interpreted in terms of harmonics of the linearized solution. (AIP)

Exact plane-wave solution of Born-Infeld electrodynamics

Exact plane-wave solution of Born-Infeld electrodynamics

A Comparison of Plane Wave Solutions in General Relativity with Those in Non-Symmetric Theory

Exact plane wave solutions of the f ild equations in general relativity and those of the field equations in nonsymmetric unified field theory are obtained under similar conditions for the case in which electromagnetic fields are present. Main properties of both solutions are compared with each other. The most important result is that, as far as the solutions dealt with are concerned, thc space-time is closely connected with the electromagnetic field in general relativity, while in nonsymmetric unified field theory the structure of the Riemannian space-time is determined quite independently of the electromagnetic field. (auth)