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Collective excitations presenting nonlinear dynamics are fundamental phenomena with broad applications. A prime example is nonlinear optics, where diverse frequency mixing processes are central to communication, sensing, wavelength…

We study the {\em propagation of electromagnetic waves} in a spacetime devoid of a metric but equipped with a {\em linear} electromagnetic spacetime relation $H\sim\chi\cdot F$. Here $H$ is the electromagnetic excitation $({\cal D},{\cal…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Guillermo F. Rubilar , Yuri N. Obukhov , Friedrich W. Hehl

We give an exhaustive, non-perturbative classification of exact travelling-wave solutions of a perturbed sine-Gordon equation (on the real line or on the circle) which is used to describe the Josephson effect in the theory of…

Mathematical Physics · Physics 2016-04-28 Gaetano Fiore , Gabriele Guerriero , Alfonso Maio , Enrico Mazziotti

Dispersive shock waves dominate wave-breaking phenomena in Hamiltonian systems. In the absence of loss, these highly irregular and disordered waves are potentially reversible. However, no experimental evidence has been given about the…

In this thesis, we re-assess some aspects of axionic electrodynamics by coupling non-linear electromagnetic effects to axion physics. We present a number of motivations to justify the coupling of the axion to the photon in terms of a…

High Energy Physics - Phenomenology · Physics 2024-08-09 Jefferson Mendes Aguiar Paixão

Oblique propagation of magnetohydrodynamic waves in warm plasmas is described by a modified vector derivative nonlinear Schroedinger equation, if charge separation in Poisson's equation and the displacement current in Ampere's law are…

solv-int · Physics 2009-10-28 Ralph Willox , Willy Hereman , Frank Verheest

We present a theory for nonlinear, resonant excitation of dynamical axions by counter-propagating electromagnetic waves in materials that break both $\mathcal{P}$ and $\mathcal{T}$ symmetries. We show that dynamical axions can mediate an…

Strongly Correlated Electrons · Physics 2024-11-26 M. Smith , Kartiek Agarwal , Ivar Martin

For k at least 2, we exhibit complete k-curvature homogeneous neutral signature pseudo-Riemannian manifolds which are not locally affine homogeneous (and hence not locally homogeneous). The curvature tensor of these manifolds is modeled on…

Differential Geometry · Mathematics 2007-05-23 Peter Gilkey , Stana Nikcevic

We discuss the prospect of using cascaded phase modulators and dispersive elements to achieve arbitrary optical waveform generation. This transform is not limited by the bandwidth of its constituent modulators and is theoretically lossless.

Optics · Physics 2025-12-11 Callum Deakin

The group theoretical approach to the relativistic wave equations on the real reducible spaces for spin~0, 1/2 and~1 massless particles is considered. The invariant wave equations which determine the appropriate irreducible representations…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Semyon Pol'shin

A non-separable wave-like integro-differential equation for the time evolution of the Wigner distribution function in phase space is educed from the corresponding separable kinetic equation. It is shown that it leads to non-local dispersion…

General Physics · Physics 2024-09-20 C Dedes

We propose a notion of a ternary skew-symmetric covariant tensor of 3rd order, consider it as a 3-dimensional matrix and study a ten-dimensional complex space of these tensors. We split this space into a direct sum of two five-dimensional…

High Energy Physics - Theory · Physics 2023-11-07 Viktor Abramov , Olga Liivapuu

We identify the nonlinear evolution equation in impact-parameter space for the "Supercritical Pomeron" in Reggeon Field Theory as a 2-dimensional stochastic Fisher and Kolmogorov-Petrovski-Piscounov equation. It exactly preserves unitarity…

High Energy Physics - Phenomenology · Physics 2014-11-20 Robi Peschanski

We present a phenomenological approach to dispersion in nonlinear elasticity. A simple, thermomechanically sound, constitutive model is proposed to describe the (non-dissipative) properties of a hyperelastic dispersive solid, without…

Soft Condensed Matter · Physics 2013-03-12 Michel Destrade , Giuseppe Saccomandi

We have extended a simple model of nonlinear diffusive shock acceleration (Berezhko and Ellison 1999) to include the injection and acceleration of electrons and the production of photons from bremsstrahlung, synchrotron, inverse-Compton,…

Astrophysics · Physics 2009-10-31 Donald C. Ellison , Evgeny G. Berezhko , Matthew G. Baring

The behavior under conformal change of the renormalized volume coefficients associated to a pseudo-Riemannian metric is investigated. It is shown that they define second order fully nonlinear operators in the conformal factor whose…

Differential Geometry · Mathematics 2008-10-24 C. Robin Graham

We construct quasimodes for some non-selfadjoint semiclassical operators at the boundary of the pseudo-spectrum using propagation of Hagedorn wave-packets. Assuming that the imaginary part of the principal symbol of the operator is…

Analysis of PDEs · Mathematics 2021-08-23 Víctor Arnaiz

We prove a Berger-type theorem which asserts that if the orthogonal subgroup generated by the torsion tensor (pulled back to a point by parallel transport) of a metric connection with skew-symmetric torsion is not transitive on the sphere,…

Differential Geometry · Mathematics 2017-10-16 Silvio Reggiani

For a knot K in $S^3$ and a regular representation $\rho$ of its group $G_K$ into SU(2) we construct a non abelian Reidemeister torsion on the first twisted cohomology group of the knot exterior. This non abelian Reidemeister torsion…

Geometric Topology · Mathematics 2007-05-23 Jérôme Dubois

We present a detailed derivation of the semiclassical propagator in the SU(n) coherent state representation. In order to provide support for immediate physical applications, we restrict this work to the fully symmetric irreducible…

Mathematical Physics · Physics 2011-05-09 Thiago F. Viscondi , Marcus A. M. de Aguiar