Bound States in the Continuum: Mechanical waves trapped indefinitely without any energy leakage within a compact, single resonator

https://www.eurekalert.org/news-releases/1080225

"overcomes resonators gradually losing energy, requiring constant energy input... whirlpools remain in place even as there are flows around them... adjusting how cylindrical granular quartz rods touch each other controls way mechanical waves interact at contact boundaries, special alignment causes polarization-protection... >1K quality factors... many cylinders connected in chain enables trapped wave modes to extend throughout chain without dispersing... low-loss: energy harvesting, sensors/ signalers, communications"

Simon Derricutt commented: "looks somewhat like a resonator, but might be somewhat over-claimed here since it has a Q of 1000 and thus it is not perfect wave-trapping and won't keep oscillating indefinitely. Quartz resonators can have Qs of 10,000 or more and thus are better at trapping energy than these BiCs. I'm not seeing from the picture at https://www.eurekalert.org/... exactly how the cylinders are attached together and exactly how they are oscillating. I'm not sure whether there is any practical use for this where it's better than another resonator, though. For cheap resonators we have piezoceramics which are often "good enough" with a Q around the 1000 mark, and for better accuracy and more-expensive we can use various cuts of Quartz crystal with a Q up to around 100,000. There's maybe some use for this or the principles behind it that I'm not seeing, though. Maybe the big thing though is that it's doing something that used to be considered impossible even if most people didn't realise it was considered impossible. Thus might lead to other stuff becoming possible"