A5067495072- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Quantum and Classical Electrodynamics
- Noncommutative and Quantum Gravity Theories
- Gyrotron and Vacuum Electronics Research
- Homotopy and Cohomology in Algebraic Topology
- Laser-Plasma Interactions and Diagnostics
- Relativity and Gravitational Theory
- Metamaterials and Metasurfaces Applications
- Quantum Electrodynamics and Casimir Effect
- High-pressure geophysics and materials
- Geophysics and Sensor Technology
- Advanced Topics in Algebra
- Solar and Space Plasma Dynamics
- Quantum Mechanics and Applications
- Algebraic structures and combinatorial models
- Microwave Engineering and Waveguides
- Particle Accelerators and Free-Electron Lasers
- Earthquake Detection and Analysis
- Photonic and Optical Devices
- Electromagnetic Scattering and Analysis
- Magnetic confinement fusion research
- Pulsars and Gravitational Waves Research
- Algebraic and Geometric Analysis
- Topological and Geometric Data Analysis
Cockcroft Institute
2015-2024
Sci-Tech Daresbury
2011-2024
University of Huddersfield
2024
Lancaster University Ghana
2024
Lancaster University
2014-2023
Daresbury Laboratory
2011-2023
Imperial College London
2019
University of Cologne
2012
Bangor University
2006
University of Oslo
2003
Transformation Optics asks Maxwell's equations what kind of electromagnetic medium recreate some smooth deformation space.The guiding principle is Einstein's covariance: that any physical theory must take the same form in coordinate system.This requirement fixes very precisely required medium.
Plasma kinetics, for both flat and curved spacetime, is conventionally performed on the mass shell, a 7--dimensional time-phase space with Vlasov vector field, also known as Liouville field. The choice of this encodes parameterisation underling 2nd order ordinary differential equations. By replacing bivector an 8--dimensional sub-bundle tangent bundle, we create free version theory. This has number advantages, which include working lightlike ultra-relativistic particles, non metric...
In the classical vacuum Maxwell-Lorentz theory self-force of a charged point particle is infinite. This makes mass renormalization necessary and, in special relativistic domain, leads to Abraham-Lorentz-Dirac equation motion possessing unphysical run-away and pre-acceleration solutions. this paper we investigate whether higher-order modification electrodynamics suggested by Bopp, Lande, Thomas Podolsky 1940s, can provide solution problem. Since linear, Green-function techniques enable one...
Temporally modulated optical media are important in both abstract and applied applications, such as spacetime transformation optics, relativistic laser-plasma interactions, dynamic metamaterials. Here we investigate the behaviour of temporal boundaries, show that traditional approaches assume constant dielectric properties, with loss incorporated an imaginary part, necessarily lead to unphysical solutions. Further, although physically reasonable predictions can be recovered a narrowband...
The electromagnetic implementation of cloaking, the hiding objects from sight by diverting and reassembling illuminating fields has now been with us ten years, while notion events is five. Both schemes as initially presented neglected inevitable dispersion that arises when a designed medium replaces vacuum under transformation. Here we define transformation design protocol incorporates both spacetime transformations dispersive material responses in natural rigorous way. We show how this...
Since a classical charged point particle radiates energy and momentum it is argued that there must be radiation reaction force. Here we present an action for the Maxwell-Lorentz without self interactions model, where each only responds to fields of other particles. The corresponding stress-energy tensor automatically conserves in Minkowski appropriate spacetimes.
The Schott term is the third order in electromagnetic self force of a charged point particle. may be obtained by integrating stress-energy-momentum tensor over side narrow hypertube enclosing section worldline. This calculation has been repeated many times using two different hypertubes known as Dirac Tube and Bhabha Tube, however previous calculations does not arise result this integration. In to regain Lorentz-Abraham-Dirac equation authors have added an ad hoc compensatory...
We give a detailed presentation of flexible method for constructing explicit expressions irrotational and incompressible fluid flows around two rigid circular moving discs. also discuss how such can be used to compute the fluid-induced forces torques on discs in terms Killing drives. Conformal mapping techniques are identify meromorphic function an annular region C with flow by Mobius transformation. First order poles correspond vortices outside Inflows incorporated putting second pole at...
By recognizing that stress–energy–momentum tensors are fundamentally related to gravitation in spacetime it is argued the classical electromagnetic properties of a simple polarizable medium may be parameterized terms constitutive tensor whose can principle determined by experiments non-inertial (accelerating) frames and presence weak but variable gravitational fields. After establishing some geometric notation, discussion given basic concepts stress, energy momentum vacuum where useful...
Spatially dispersive (also known as non‐local) electromagnetic media are considered where the parameters defining permittivity relation vary periodically. Maxwell's equations give rise to a difference equation corresponding Floquet modes. A complete set of approximate solutions is calculated which valid when inhomogeneity small. This applied inhomogeneous wire media. new feature arises considering spatially media, that existence coupled
We analyse the problem of one-dimensional quantum mechanics on arbitrary graphs as idealized models for systems spaces with non-trivial topologies. In particular we argue that such can be made to accommodate physical characteristics wavefunctions a network wires and offer several derivations junction condition. Throughout adopt continuity condition wavefunction at each primitive node in network. Results are applied energy spectrum system containing one infinitely many junctions.
The notion of a 2-point susceptibility kernel used to describe linear electromagnetic responses dispersive continuous media in nonrelativistic phenomena is generalized accommodate the constraints required causal formulation spacetimes with background gravitational fields. In particular concepts spatial material inhomogeneity and temporal nonstationarity are formulated within fully covariant spacetime framework. This framework illustrated by recasting Maxwell–Vlasov equations for...
A kinetic theory is developed to describe radiating electrons whose motion governed by the Lorentz-Dirac equation. This gives rise a generalized Vlasov equation coupled an for evolution of physical submanifold phase space. The pathological solutions 1-particle may be removed expanding latter in powers τ ≔ q2/6πm. radiation-induced change entropy explored and its origin discussed. As simple demonstration theory, radiative damping rate longitudinal plasma waves calculated.
Models of covariant linear electromagnetic constitutive relations are formulated that have wide applicability to the computation susceptibility tensors for dispersive and inhomogeneous media.A perturbative framework is used derive a relation globally neutral plasma enabling one describe in this context generalized Landau damping mechanism non-stationary states.
We show how the standard constitutive assumptions for macroscopic Maxwell equations can be relaxed. This is done by arguing that Maxwellian excitation fields ($\mathbit{D}$, $\mathbit{H}$) should dispensed with, on grounds they (a) cannot measured, and (b) act solely as gauge potentials charge current. In resulting theory, it only links between ($\mathbit{E}$, $\mathbit{B}$) current ($\ensuremath{\rho}$, $\mathbit{J}$) matter; so we introduce appropriate linear operator combine Gauss...
We show how spatial dispersion can be used as a mechanism to customize the longitudinal profiles of electric fields inside modulated wire media, using fast and remarkably accurate 1D inhomogeneous model. This customization gives fine control sub-wavelength behaviour field, has been achieved recently for transverse in simpler slotted-slab media. Our scheme avoids any necessity run long series computationally intensive 3D simulations specific structures, order iteratively converge (or...
Despite being studied for over a century, the use of quadrupoles have been limited to Cartesian coordinates in flat spacetime due incorrect transformation rules used define them. Here correct are derived, which particularly unusual as they involve second derivatives coordinate and an integral. Transformations involving integrals not seen before. This is significantly different from familiar dipole, where components transform tensors. It enables be correctly defined general relativity...
Electromagnetic mode profile shaping would be a very useful technique, with applications including in accelerator science and data transmission. Two methods are proposed: one varying the permittivity other using wire medium. By use of Mathieu functions, we demonstrate flatter, triangular peakier profile. The first two may used to manipulate longer particle bunches, while last could on shorter bunches It is also demonstrated how further improvements can achieved by going beyond functions.
We investigate stress-energy tensors constructed from the covariant derivatives of delta functions on a worldline. Since are used all components transform as tensors. derive dynamical equations for components, up to quadrupole order. The do, however, depend in non-tensorial way, choice vector along also number important results about general multipoles, including that their unique, and multipoles can be written using derivatives. show how multipole related standard moments tensor field, by...
A formulation of the dynamics a collection connected simple 1‐dimensional Cosserat continua and rigid bodies is presented in terms sections an SO(3) fibration over net. large class junction conditions considered unified framework. All equations motion are derived as extrema constrained variational principle on net analysed perturbatively for structures with Kirchhoff constitutive properties. The whole discussion based notion its contractions obtained by taking certain limits that transform...