Publications
103 results found
Kinsler P, McCall MW, Oulton RF, et al., 2022, The surprising persistence of time-dependent quantum entanglement, New Journal of Physics, Vol: 24, Pages: 1-14, ISSN: 1367-2630
The mismatch between elegant theoretical models and the detailed experimental reality is particularly pronounced in quantum nonlinear interferometry (QNI). In stark contrast to theory, experiments contain pump beams that start in impure states and that are depleted, quantum noise that affects—and drives—any otherwise gradual build up of the signal and idler fields, and nonlinear materials that are far from ideal and have a complicated time-dependent dispersive response. Notably, we would normally expect group velocity mismatches to destroy any possibility of measurable or visible entanglement, even though it remains intact—the mismatches change the relative timings of induced signal–idler entanglements, thus generating 'which path' information. Using an approach based on the positive-P representation, which is ideally suited to such problems, we are able to keep detailed track of the time-domain entanglement crucial for QNI. This allows us to show that entanglement can be—and is—recoverable despite the obscuring effects of real-world complications; and that recovery is attributable to an implicit time-averaging present in the detection process.
Gratus J, Seviour R, Kinsler P, et al., 2021, Temporal boundaries in electromagnetic materials, NEW JOURNAL OF PHYSICS, Vol: 23, ISSN: 1367-2630
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- Citations: 7
Gratus J, Kinsler P, McCall MW, 2021, Temporary Singularities and Axions: An Analytic Solution that Challenges Charge Conservation, ANNALEN DER PHYSIK, Vol: 533, ISSN: 0003-3804
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- Citations: 2
Kinsler P, 2021, A new introduction to spatial dispersion: Reimagining the basic concepts, Publisher: ELSEVIER
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- Citations: 2
McCall M, Kinsler P, Tymms V, 2020, Catapult Description of Magnetic Fields and Forces, PHYSICS TEACHER, Vol: 58, Pages: 416-417, ISSN: 0031-921X
Kinsler P, 2020, Faraday's Law and Magnetic Induction: Cause and Effect, Experiment and Theory, PHYSICS, Vol: 2, Pages: 150-163
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- Citations: 9
Gratus J, McCall MW, Kinsler P, 2020, Electromagnetism, axions, and topology: A first-order operator approach to constitutive responses provides greater freedom, Physical Review A: Atomic, Molecular and Optical Physics, Vol: 101, Pages: 043804-1-043804-18, ISSN: 1050-2947
We show how the standard constitutive assumptions for the macroscopic Maxwell equations can be relaxed. This is done by arguing that the Maxwellian excitation fields (D, H) should be dispensed with, on the grounds that they (a) cannot be measured, and (b) act solely as gauge potentials for the charge and current. In the resulting theory, it is only the links between the fields (E, B) and the charge and current (ρ, J) that matter; and so we introduce appropriate linear operator equations that combine the Gauss and Maxwell-Ampère equations with the constitutive relations, eliminating (D, H). The result is that we can admit more types of electromagnetic media, notably, these relations can allow coupling in the bulk to a homogeneous axionic material; in contrast to standard electromagnetism where any homogeneous axionlike field is completely decoupled in the bulk, and only accessible at boundaries. We also consider a wider context, including the role of topology, extended nonaxionic constitutive parameters, and treatment of Ohmic currents. A range of examples including an axionic response material is presented, including static electromagnetic scenarios, a possible metamaterial implementation, and how the transformation optics paradigm would be modified. Notably, these examples include one where topological considerations make it impossible to model using (D, H).
Gratus J, Kinsler P, McCall M, 2019, Evaporating black-holes, wormholes, and vacuum polarisation: must they always conserve charge?, Foundations of Physics, Vol: 49, Pages: 330-350, ISSN: 0015-9018
A careful examination of the fundamentals of electromagnetic theory showsthat due to the underlying mathematical assumptions required for Stokes’ Theorem,global charge conservation cannot be guaranteed in topologically non-trivial space-times. However, in order to break the charge conservation mechanism we must alsoallow the electromagnetic excitation fieldsD,Hto possess a gauge freedom, just asthe electromagnetic scalar and vector potentialsφandAdo. This has implicationsfor the treatment of electromagnetism in spacetimes where black holes both form andthen evaporate, as well as extending the possibilities for treating vacuum polarisation.Using this gauge freedom ofD,Hwe also propose an alternative to the acceptednotion that a charge passing through a wormhole necessarily leads to an additional(effective) charge on the wormhole’s mouth.
Gratus J, Kinsler P, McCall MW, 2019, Maxwell's (D, H) excitation fields: lessons from permanent magnets, EUROPEAN JOURNAL OF PHYSICS, Vol: 40, ISSN: 0143-0807
Boyd T, Gratus J, Kinsler P, et al., 2018, Mode Profile Shaping in Wire Media: Towards An Experimental Verification, APPLIED SCIENCES-BASEL, Vol: 8, ISSN: 2076-3417
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- Citations: 2
Kinsler P, 2018, Stylized innovation: generating timelines by interrogating incrementally available randomised dictionaries
A key challenge when trying to understand innovation is that it is a dynamic,ongoing process, which can be highly contingent on ephemeral factors such asculture, economics, or luck. This means that any analysis of the real-worldprocess must necessarily be historical - and thus probably too late to be mostuseful - but also cannot be sure what the properties of the web of connectionsbetween innovations is or was. Here I try to address this by designing andgenerating a set of synthetic innovation web "dictionaries" that can be used tohost sampled innovation timelines, probe the overall statistics and behavioursof these processes, and determine the degree of their reliance on the structureor generating algorithm. Thus, inspired by the work of Fink, Reeves, Palma andFarr (2017) on innovation in language, gastronomy, and technology, I study hownew symbol discovery manifests itself in terms of additional "word" vocabularybeing available from dictionaries generated from a finite number of symbols.Several distinct dictionary generation models are investigated using numericalsimulation, with emphasis on the scaling of knowledge as dictionary generatorsand parameters are varied, and the role of which order the symbols arediscovered in.
McCall M, Pendry J, Galdi V, et al., 2018, Roadmap on transformation optics, Journal of Optics A: Pure and Applied Optics, Vol: 20, ISSN: 1464-4258
Transformation Optics asks Maxwell’s equations what kind of electromagnetic medium recreate some smooth deformation of space. The guiding principle is Einstein’s principle of covariance: that any physical theory must take the same form in any coordinate system. This requirement fixes very precisely the required electromagnetic medium.The impact of this insight cannot be overestimated. Many practitioners were used to thinking that only a few analytic solutions to Maxwell’s equations existed, such as the monochromatic plane wave in a homogeneous, isotropic medium. At a stroke, Transformation Optics increases that landscape from ‘few’ to ‘infinity’, and to each of the infinitude of analytic solutions dreamt up by the researcher, corresponds an electromagnetic medium capable of reproducing that solution precisely. The most striking example is the electromagnetic cloak, thought to be an unreachable dream of science fiction writers, but realised in the laboratory a few months after the papers proposing the possibility were published. But the practical challenges are considerable, requiring meta-media that are at once electrically and magnetically inhomogeneous and anisotropic. How far have we come since the first demonstrations over a decade ago? And what does the future hold? If the wizardry of perfect macroscopic optical invisibility still eludes us in practice, then what compromises still enable us to create interesting, useful, devices? While 3D cloaking remains a significant technical challenge, much progress has been made in 2-dimensions. Carpet cloaking, wherein an object is hidden under a surface that appears optically flat, relaxes the constraints of extreme electromagnetic parameters. Surface wave cloaking guides sub-wavelength surface waves, making uneven surfaces appear flat. Two dimensions is also the setting in which conformal and complex coordinate transformations are realisable, and the possibilities in this restr
Kinsler P, 2018, Impedance rescaling and scattering from transformation optics devices, JOURNAL OF PHYSICS COMMUNICATIONS, Vol: 2, ISSN: 2399-6528
Boyd T, Gratus J, Kinsler P, et al., 2018, Customizing longitudinal electric field profiles using spatial dispersion in dielectric wire arrays, OPTICS EXPRESS, Vol: 26, Pages: 2478-2494, ISSN: 1094-4087
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- Citations: 5
Kinsler P, 2018, A comparison of the factorization approach to temporal and spatial propagation in the case of some acoustic waves, JOURNAL OF PHYSICS COMMUNICATIONS, Vol: 2, ISSN: 2399-6528
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- Citations: 3
Kinsler P, 2018, Uni-directional optical pulses, temporal propagation, and spatial and temporal dispersion, JOURNAL OF OPTICS, Vol: 20, ISSN: 2040-8978
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- Citations: 6
Kinsler P, McCall MW, 2017, Generalized transformation design: metrics, speeds, and diffusion, Wave Motion, Vol: 77, Pages: 91-106, ISSN: 0165-2125
We show that a unified and maximally generalized approach to spatialtransformation design is possible, one that encompasses all second order waves,rays, and diffusion processes in anisotropic media. Until the final step, it isunnecessary to specify the physical process for which a specific transformationdesign is to be implemented. The principal approximation is the neglect of waveimpedance, an attribute that plays no role in ray propagation, and is thereforeirrelevant for pure ray devices; another constraint is that for waves thespatial variation in material parameters needs to be sufficiently smallcompared with the wavelength. The key link between our general formulation anda specific implementation is how the spatial metric relates to the speed ofdisturbance in a given medium, whether it is electromagnetic, acoustic, ordiffusive. Notably, we show that our generalised ray theory, in allowing foranisotropic indexes (speeds), generates the same predictions as does a wavetheory, and the results are closely related to those for diffusion processes.
McCall MW, Kinsler P, 2017, Space-time Cloaking, World Scientific Handbook of Metamaterials and Plasmonics: In 4 Volumes, Editors: Craster, Guenneau, Publisher: World Scientific Series in Nan, Pages: 173-203, ISBN: 9789813227613
Gratus J, Kinsler P, Letizia R, et al., 2017, Subwavelength mode profile customization using functional materials, JOURNAL OF PHYSICS COMMUNICATIONS, Vol: 1, ISSN: 2399-6528
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- Citations: 2
Gratus J, Kinsler P, Letizia R, et al., 2017, Electromagnetic mode profile shaping in waveguides, APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, Vol: 123, ISSN: 0947-8396
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- Citations: 5
McCall MW, Gratus J, Kinsler P, et al., 2016, On spacetime transformation optics: temporal and spatial dispersion, New Journal of Physics, Vol: 18, ISSN: 1367-2630
The electromagnetic implementation of cloaking, the hiding ofobjectsfrom sight by di-verting and reassembling illuminating electromagnetic fields has now been with us ten years,while the notion of hidingeventsis now five. Both schemes as initially presented neglectedthe inevitable dispersion that arises when a designed medium replaces vacuum under trans-formation. Here we define a transformation design protocol that incorporates both spacetimetransformations and dispersive material responses in a natural and rigorous way. We showhow this methodology is applied to an event cloak designed to appear as a homogeneousand isotropic butdispersivemedium. The consequences for spacetime transformation de-sign in dispersive materials are discussed, and some parameter and bandwidth constraintsidentified.
Kinsler P, Gratus J, McCall MW, et al., 2016, Dispersion in space-time transformation optics, URSI International Symposium on Electromagnetic Theory (EMTS), Publisher: IEEE, ISSN: 2163-405X
The use of spacetime cloaking to hide events is an intriguing trick, but the unavoidable presence of dispersion limits the performance of any implementation, and needs to be accounted for. We show how the dispersion changes under transformation.
McCall MW, Kinsler P, Topf RDM, 2016, The refractive index of reciprocal electromagnetic media, Journal of Optics, Vol: 18, ISSN: 2040-8978
We study the electromagnetics of media described by identical inhomogeneous relative dielectric and magnetic tensors, ${\boldsymbol{\epsilon }}={\boldsymbol{\mu }}.$ Such media occur generically as spatial transformation media, i.e. electromagnetic media that are defined by a deformation of space. We show that such media are completely described by a refractive index $n({\bf{r}},\hat{{\bf{s}}})$ that depends on position ${\bf{r}}$ and direction $\hat{{\bf{s}}},$ but is independent of polarization. The phase surface is always ellipsoidal, and $n({\bf{r}},\hat{{\bf{s}}})$ is therefore represented by the radius vector to the surface of the ellipsoid. We apply our method to calculate the angular dependence of the refractive index in the well-studied cylindrical cloak and to a new kind of structurally chiral medium induced by a twist deformation. By way of a simple example we also show that media for which ${\boldsymbol{\epsilon }}={\boldsymbol{\mu }}$ do not in general preserve the impedance properties of vacuum. The implications of this somewhat surprising conclusion for the field of transformation optics are discussed.
McCall M, Kinsler P, 2016, The Limits and Extension of Transformation Optics, URSI International Symposium on Electromagnetic Theory (EMTS), Publisher: IEEE, Pages: 603-604, ISSN: 2163-405X
Boyd T, Kinsler P, Gratus J, et al., 2016, Electromagnetic Mode Profile Shaping in Waveguides, URSI International Symposium on Electromagnetic Theory (EMTS), Publisher: IEEE, Pages: 725-727, ISSN: 2163-405X
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- Citations: 1
Kinsler P, 2015, Measure for carrier shocking, Journal of the Optical Society of America B - Optical Physics, Vol: 32, Pages: 1889-1893, ISSN: 0740-3224
I propose a definition for a “shocking coefficient” S intended to make determinations of the degree of waveform shocking, and comparisons thereof, more quantitative. This means we can avoid having to make ad hoc judgments on the basis of the visual comparison of wave profiles.
Kinsler P, McCall MW, 2015, The futures of transformations and metamaterials, Photonics and Nanostructures-Fundamentals and Applications, Vol: 15, Pages: 10-23, ISSN: 1569-4429
Kinsler P, McCall MW, 2014, Transformation devices: Event carpets in space and space-time, PHYSICAL REVIEW A, Vol: 89, ISSN: 1050-2947
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- Citations: 16
Kinsler P, McCall MW, 2014, Cloaks, editors, and bubbles: applications of spacetime transformation theory, Annalen der Physik, Vol: 526, Pages: 51-62, ISSN: 0003-3804
Spacetime or ‘event’ cloaking was recently introduced as a concept, and the theoretical design for such a cloak was presented for illumination by electromagnetic waves [McCall et al., J. Opt. 2011]. Here it is described how event cloaks can be designed for simple wave systems, using either an approximate ‘speed cloak’ method, or an exact full‐wave one. Further, details of many of the implications of spacetime transformation devices are discussed, including their (usually) directional nature, spacetime distortions (as opposed to cloaks), and how leaky cloaks manifest themselves. More exotic concepts are also addressed, in particular concepts that follow naturally on from considerations of simple spacetime transformation devices, such as spacetime modeling and causality editors. A proposal for implementing an interrupt‐without‐interrupt concept is described. Finally, the design for a time‐dependent ‘bubbleverse’ is presented, based on temporally modulated Maxwell's Fisheye transformation device (T‐device) in a flat background spacetime.
Kinsler P, 2013, How to be causal: time, spacetime, and spectra (vol 32, pg 1687, 2011), EUROPEAN JOURNAL OF PHYSICS, Vol: 34, Pages: 205-205, ISSN: 0143-0807
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