I've found several articles discussing experimental evidence of a deuterium state of densities over $140 \textrm{ kg}/\textrm{cm}^3$:

• F. Winterberg. Ultradense Deuterium. arXiv.

• Shahriar Badiei, Patrik U. Andersson, Leif Holmlid. High-energy Coulomb explosions in ultra-dense deuterium: Time-of-flight-mass spectrometry with variable energy and flight length. International Journal of Mass Spectrometry, Volume 282, Issues 1–2, 15 April 2009, Pages 70-76. DOI.

• Patrik U. Andersson, Leif Holmlid. Superfluid ultra-dense deuterium D(−1) at room temperature. Physics Letters A, Volume 375, Issue 10, 7 March 2011, Pages 1344-1347. DOI.

Have these super-dense states been replicated by third parties?

Have these super-dense states yet to be replicated by third-parties?

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Never heard of any of this. Interesting papers, certainly non-trivial in their data coverage. But wow... wouldn't this be Nobel prize territory if some small group really has found any type of room-temperature superconductivity? The densities quoted offhand seem extremely unexpected for electron-cancelled condensates of any sort, nuclear or not (D(-1) being of course a nuclear-sized boson), but the quasi-2D surface is... a factor. Third-party replication would indeed would be nice, there's an understatement! –  Terry Bollinger Sep 10 '12 at 18:07
@TerryBollinger, apparently the superconductivity is inferred, not directly measured, since they haven't been able to create more than a hundred atom samples, at least this is what they seem to imply –  diffeomorphism Sep 10 '12 at 18:23
Ah, hmm! Well, they'll need to get well beyond inferred to get to that Nobel Prize. They'll also need to explain that density issue. Maybe they do in their papers, maybe not? I'll definitely look. But such densities are so unexpected that they will require some serious attention to the question of how to achieve them if only room-temp electrons are electrons available to cancel out positive charge. Hmm, maybe Fermi sea surface electrons? Those can have shorter wavelengths, up to X-ray range electron energies, but short enough? Seems unlikely... –  Terry Bollinger Sep 10 '12 at 19:19
Can you link to some free versions of the experimental papers? –  Ron Maimon Sep 11 '12 at 7:10
Rydberg? Hmm. Well, that saves me some time; it tells me the papers very likely aren't worth reading. Invoking the gigantic, near-classical high-energy electron continuum states of Rydberg atoms at a solid lattice interface just makes no obvious sense, especially not geometrically. And in any case, Rydberg orbits reduce the electron density near the nucleus very close to zero, leaving bare deuterons for which high densities are harder to explain, not easier. So, feel free to speculate or suggest why Rydberg states might help instead of hurt, but I think I just lost interest in these papers. –  Terry Bollinger Sep 14 '12 at 3:29

Have these super-dense states been replicated by third parties?

No, I don't think there has been anything published in any reputable journal claiming to have reproduced Holmlid's supposed experimental discovery of ultradense deuterium. If there had been, it would have been big news.

He is active in the cold fusion community, so it would not be surprising if other cold-fusion kooks did similar experiments and presented them at true-believer conferences, etc. Holmlid is basically a one-man echo chamber who tirelessly pushes his crackpottery in online venues such as Wikipedia and physics.SE. Although he has managed to get his articles published in journals, a literature search showed that out of 2154 references to his papers, 1863 were self-citations.

Extraordinary claims require extraordinary evidence. Holmlid's claims, about both "Rydberg matter" and "ultradense deuterium," are extraordinary, and there is no evidence for them from any reputable experimentalist.

By the way, he has another, more recent paper claiming laser-induced fusion in ultradense deuterium: http://arxiv.org/abs/1302.2781

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I follow the publications of Holmlid since two years. His explanation of p(-1) and D(-1) as "inverted" Rydberg matter seemed strange to me too. But in his latest publication (http://dx.doi.org/10.1016/j.ijms.2013.08.003) he explains these hyperdense forms of protium and deuterium as Bose-Einstein Condensates and he refers to the theory of Jorge Hirsch about superconductivity and the Meissner effect (arXiv:0908.1577v1 [cond-mat.supr-con] 12 Aug 2009).

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protected by Qmechanic♦Oct 6 '13 at 17:33

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