Almost all of the articles on ultra-dense deuterium currently are from Professor Leif Holmlid. In somewhat of a catch-22, the fact that there have been very few replication attempts to date is likely the reason that there is little interest in further investigating Holmlid’s claims.
As such, I want to mention all of the replication efforts I’m aware of.
The first item of note is not an experiment, but theory. The purpose of theory is to explain experimental evidence and anticipate the answer to future questions without the need for experimentation. As such, theory is tested by first issuing predictions, and then testing those predictions empirically. The only theorist to comment on Holmlids work is by Friedwardt Winterberg. Besides the fact that his theory was published in 2010, and is based on evidence that is now somewhat outdated, I don’t have much to say about it. Unfortunately, since it doesn’t make immediately testable predictions, and hasn’t been updated in 8 years, it doesn’t provide much support for Holmlid’s claims.
The next relevant work I’m aware of began in 2015, when two others, PhD candidate Sindre ZG, and his advisor, Professor Svienn Olafsson from the University of Iceland, began working with Leif Holmlid to replicate this work. Sveinn himself has published three articles on the matter as a co-author with Leif (Charged Particle Energy Spectra, Spontaneous Emissions, Muon Detection) He also reported one (apparently non-replicable) piece of evidence at the ICCF-21 conference: with a 4-point conductivity probe measuring a platinum on magnesium oxide target, he claims to have detected sudden drops in resistivity of the surface after deposition of ultra-dense deuterium.
Sindre ZG also gave a talk at ICCF-21, and described his process trying to replicate Holmlid’s experiments. His general approach has been to test for laser-induced high-energy particle emissions from the ultra-dense deuterium.
The last person working the field (that I’m aware of) is Mike Taggett, an entrepreneur in Utah who has been working on ultra-dense deuterium off and on for about 6 years. When I talked to him recently, he described having visited over 20 physics departments to find someone willing to collaborate. While he said he found a couple leads at different points, most departments were scared away by the fear of cold-fusion-esque results.
I’ve reached out to all of these researchers to find out more details about their experiments, future plans, and those they’ve worked with.