Catching up on some cloaking research that was published after the bulk of my invisibility book was finished — lots of interesting stuff has been happening!
One thing I stress in my discussions of invisibility is that the science and technology is being explored for more than just hiding things from visible light. If we can guide light waves around a central region and send them on their way, we can do similar things with other types of waves. I’ve written before about serious proposals to use cloaking to protect buildings from earthquake waves, and in 2012 a theoretical paper was published about how it might be possible to design cloaking devices to protect offshore structures from ocean waves.
The principles of cloaking have even been used in the design of cloaks for things that are not even waves. A “thermal cloak” was introduced in 2012, which guides heat around a central hidden region, keeping the central region shielded. Similar cloaks have been introduced for static electric and magnetic fields.
I thought I had seen it all when it comes to cloaking, but I was totally surprised when I came across a paper titled “Chemical Cloaking,” published in 2020 in Physical Review E by Avanzini, Falasco and Esposito! The paper introduces the possibility of hiding an object in a fluid flow by using active chemical reactions!
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