Thanks for the paper link. Fun to see it show up on HN. I did my PhD in this area and am familiar with the Engels group (one of my papers is cited by theirs).

Thanks for the paper link. Fun to see it show up on HN. I did my PhD in this area and am familiar with the Engels group (one of my papers is cited by theirs). You're correct that this is no ordinary fluid, but observing "negative mass" type behavior is a nice find (a theory paper about this came out just recently). There is a massive amount of work being done in this area. The Engels group did a nice job of presenting a paper that captures some of the progress in the field and the broader impacts of the work. I must commend the article for doing a good with the PR side of things... other physicists would have done the same work and buried it in an obscure language that would have drawn zero interest.