Yeah, I found the original hype overblown. The claims made were also for a configuration that was odd, at best. Intuitively, there are any number of geometries

Yeah, I found the original hype overblown. The claims made were also for a configuration that was odd, at best. Intuitively, there are any number of geometries that ought to produce greater 'negative energy densities' while being easier to manufacture and test than the sphere-in-a-cylinder one if the proposed effect isn't just a mathematical artifact.