Physicists at Purdue University in Indiana claim to have found new evidence for nuclear fusion in a tabletop device. Yiban Xu and Adam Butt say that firing sound waves into a beaker of deuterated acetone that has been "seeded" with neutrons produces tritium and further neutrons through the process of fusion. Known as "bubble fusion", the phenomenon met with widespread scepticism when it was first reported in 2002. The new results are likely to be just as controversial.
This is a third (independent) confirmation of a nuclear fusion process in normal conditions. However, other scientists are already contesting these results as well.
Aaron Galonsky of Michigan State University, who was sceptical of Taleyarkhan's original results, is sceptical again. He explains that the pulses of neutrons the Purdue team see could be coming from the enormous neutron source, which emits over 2 million neutrons per second. Many of the pulses might not be from neutrons at all but from the 2.2 MeV gamma rays resulting from thermalization and capture of source neutrons by the hydrogen in the paraffin walls of the chamber. Xu and Butt give no explanation for these pulses or indeed the neutron pulses they observe in ordinary acetone, he adds.
Whatever would be the truth, we will see in a few years. However, it is funny that this controversial theory stayed for so long in the academic community, with no parts coming with a decisive argument one way or the other.