arXiv research

We consider restrictions placed by geodesic completeness on spacetimes possessing a null parallel vector field, the so-called Brinkmann spacetimes. This class of spacetimes includes important idealized gravitational wave models in General Relativity, namely the plane-fronted waves with parallel rays, or pp-waves, which…

Develops complex spinorial forms for all dimensions and signatures, proving Brinkmann waves in supergravity.

Study isotropic solutions in smooth metric measure spaces with vacuum Einstein equations.

Geodesic completeness and flow properties of compact Brinkmann spacetimes proven.

As a difference with the positive-definite Riemannian case, in the Lorentzian case there exists proper second-order symmetric spacetimes, i.e., those with vanishing second covariant derivative of the Riemannian tensor ($R_{λμνρ;α;β}=0$) which are not locally symmetric ($R_{λμνρ;α}\neq 0$). In fact, they lie in the clas…

Mathematical treatment of plane waves, proving their inextendibility and completeness.

Second-order symmetric Lorentzian spaces, that is to say, Lorentzian manifolds with vanishing second derivative of the curvature tensor R, are characterized by several geometric properties, and explicitly presented. Locally, they are a product M=M_1 x M_2 where each factor is uniquely determined as follows: M_2 is a Ri…

We study the geometric structure of Lorentzian spin manifolds, which admit imaginary Killing spinors. The discussion is based on the cone construction and a normal form classification of skew-adjoint operators in signature $(2,n-2)$. Derived geometries include Brinkmann spaces, Lorentzian Einstein-Sasaki spaces and cer…

The n-dimensional Lorentzian manifolds with vanishing second covariant derivative of the Riemann tensor (2-symmetric spacetimes) are characterized and classified. The main result is that either they are locally symmetric or they have a covariantly constant null vector field, in this case defining a subfamily of Brinkma…

We show that an orientable pseudo-Anosov homeomorphism has vanishing Sah-Arnoux-Fathi invariant if and only if the minimal polynomial of its dilatation is not reciprocal. We relate this to works of Margalit-Spallone and Birman, Brinkmann and Kawamuro. Mainly, we use Veech's construction of pseudo-Anosov maps to give ex…

Geodesic completeness proven for all compact locally symmetric Lorentz manifolds.

We describe the local conformal geometry of a Lorentzian spin manifold $(M,g)$ admitting a twistor spinor $φ$ with zero. Moreover, we describe the shape of the zero set of $φ$. If $φ$ has isolated zeros then the metric $g$ is locally conformally equivalent to a static monopole. In the other case the zero set consists o…

Study proves interaction of three impulsive gravitational waves, showing local solution and Lipschitz continuity.

New Galilean spacetimes found as pp-wave reductions.

Analyzes Gerstner's trochoidal waves and their geometric properties.

Wave fronts on certain surfaces become dense.

Analyzes properties of stiffness tensors for elastic wave imaging.

Deep learning model predicts wind-wave relationship.

Impulsive waves contradict a 1962 conjecture about pp-waves.

Extends Penrose limit to Finsler spacetimes.

New findings on plane waves in 3D spacetimes, showing non-unimodular elliptic plane waves are unique.

Classifies solutions to vacuum weighted Einstein equations on pr-waves.

High frequency limit for most of wave phenomena is known as quasiclassical limit or ray optics limit. Propagation of waves in this limit is described in terms of wave fronts and rays. Wave front is a surface of constant phase whose points are moving along rays. As it appears, their motion can be described by Hamilton e…

Study compact plane waves, showing they are essentially standard.

New method finds precise late-time behavior of wave equations.

We characterize singularities of focal surfaces of wave fronts in terms of differential geometric properties of the initial wave fronts. Moreover, we study relationships between geometric properties of focal surfaces and geometric invariants of the initial wave fronts.

Paper explores non-uniqueness and uniqueness class for wave equations on graphs.

The financial rogue waves are reported analytically in the nonlinear option pricing model due to Ivancevic, which is nonlinear wave alternative of the Black-Scholes model. These solutions may be used to describe the possible physical mechanisms for rogue wave phenomenon in financial markets and related fields.

New metrics link Kähler and pp-wave spacetimes.

We show that every n-dimensional locally homogeneous pp-wave is a plane wave, provided it is indecomposable and its curvature operator, when acting on $2$-forms, has rank greater than one. As a consequence we obtain that indecomposable, Ricci-flat locally homogeneous pp-waves are plane waves. This generalises a classic…

The paper shows how null hypersurfaces behave in Lorentz-Minkowski space.

New metrics constructed dual to specific wave-like geometries.

Study pp-waves with lightlike parallel spinors in vacuum spacetimes.

Develops methods to construct harmonic and wave maps into variable-curvature surfaces.

Unique solutions found for wave-like decaying null infinity equations.

The main objective of the present paper is to investigate the curvature properties of generalized pp-wave metric. It is shown that generalized pp-wave spacetime is Ricci generalized pseudosymmetric, 2-quasi-Einstein and generalized quasi-Einstein in the sense of Chaki. As a special case it is shown that pp-wave spaceti…

Measuring wave sources uniquely identifies manifold properties.

We explore the plane-wave limit of homogeneous spacetimes. For plane-wave limits along homogeneous geodesics the limit is known to be homogeneous and we exhibit the limiting metric in terms of Lie algebraic data. This simplifies many calculations and we illustrate this with several examples. We also investigate the beh…

Shorter proof for wave front length in Euclidean disk

Study finds rigid submanifolds in spacelike waves under specific conditions.

The wave trace of certain convex domains can be smooth near some points in the length spectrum.

Initial data for $pp$-wave spacetimes constructed in 4D.

Global solutions found for a wave-Klein-Gordon system with strong couplings in divergence form.

Recently, a novel adaptive wave model for financial option pricing has been proposed in the form of adaptive nonlinear Schrödinger (NLS) equation [Ivancevic a], as a high-complexity alternative to the linear Black-Scholes-Merton model [Black-Scholes-Merton]. Its quantum-mechanical basis has been elaborated in [Ivancevi…

Study gauge freedoms in elastic wave equations and Dirichlet-to-Neumann map.

The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black-Scholes option pricing model. In this…

Epilepsy is an important public health issue. An appropriate epileptiform discharge pattern detection of this neurological disease is a typical problem in biomedical engineering. In this paper, a new method is proposed for spike-and-wave discharge pattern detection based on Kendall's Tau-b coefficient. The proposed app…

Geometric flow on curves in S^3 generates YO equations solutions.