Fine Structure

Acoustic Black Holes

Today brings us an interesting article on Bose Einstein Condensates which can be manipulated into creating "acoustic black holes" which trap all sound waves within a certain radius of the BEC. The interesting part is that the article suggests that these acoustic black holes should exhibit Hawking Radiation which doesn't really strike me as making any sense at all. How do you get quantum vacuum fluctuations of sound waves? I'd appreciate any ideas in the comments. ]