A spacetime cloak, or a history editor

Abstract

We introduce a recipe for producing a new type of electromagnetic cloak, the electromagnetic spacetime cloak, which conceals events rather than mere objects. Non-emitting events occurring during a restricted period are never suspected by a distant observer. The cloak works by locally manipulating the speed of light of an initially uniform light distribution, whilst the light rays themselves always follow straight paths. Any 'perfect' spacetime cloak would necessarily rely upon the technology of electromagnetic metamaterials, which has already been shown to be capable of deforming light in ways hitherto unforseen -to produce for example an electromagnetic object cloak. Nevertheless, we show how it is possible to use intensity dependent refractive indices to construct an approximate STC, an implementation that would enable the distinct signature of successful event cloaking to be observed. Potential demonstrations include systems that apparently violate quantum statistics, 'interrupt-without-interrupt' computation on convergent data channels, and the illusion of a Star-Trek transporter. * Electronic address: m.mccall@imperial.ac.uk

Some thoughts on spacetime transformation theory

“…Nevertheless, this is a key issue today and the paper by Kinsler and McCall is absolutely fascinating [4]. It involves concepts that go beyond the original paper "A spacetime cloak, or a history editor" [5] and it introduces the new and exciting idea called the "bubbleverse" -an idea that will stimulate researchers and laymen alike.…”

“…As stated above, the concept of the spacetime cloak was first introduced by McCall et al in 2011 [5], and it immediately opened up an exciting cloaking window on events, rather than just objects. This leap forward also shows how such cloaks can, in principle, be realised in the laboratory, using ideas based on refractive index control in optical fibres.…”

Diffusive-light invisibility cloak for transient illumination

“…* cargarm2@ntc.upv.es Nevertheless, the TO and scattering cancellation principles are more appropriate for cloaking objects in the absence of a ground plane, and have been successfully adopted in different fields besides wave optics. For example, transformational cloaks have been designed for thermodynamics [12], acoustics [13], matter waves [14], and even for the space-time domain [15][16][17] and moving media [18,19]. Likewise, scattering cancellation has been applied, e.g., to the fields of light diffusion [20], elasticity, and acoustics [21,22].…”

Dispersion in space-time transformation optics

“…The notion of hiding events is now five years old [2]. Both schemes as initially introduced, however, neglected one crucial component that, ironically, made them possible in the first place.…”