Bubble fusion scientist disciplined

After making headlines with claims of achieving nuclear fusion in a tabletop experiment, Rusi Taleyarkhan joined Purdue University’s nuclear engineering department in 2004. His tenure there has been rocky. After a university investigation cited Taleyarkhan for two instances of research misconduct, the university imposed sanctions in August. Taleyarkhan will remain a member of the university’s faculty and can serve on graduate committees, but he will no longer have a named professorship and will not be allowed to serve as a major professor for graduate students for at least three years.

The saga began in 2002, when Taleyarkhan was at Oak Ridge National Laboratory. He and his colleagues had subjected a flask of deuterated acetone to very intense, high-frequency sound waves, causing the formation of tiny bubbles that expanded and contracted in phase with the sound. Theorists had predicted that the compression-induced shock wave in a sufficiently spherical bubble could create high enough temperatures and pressures for deuterons to fuse. Taleyarkhan’s team presented evidence that such fusion had indeed occurred. But their report, published in Science, met with considerable skepticism. (See Physics Today, April 2002, page 16 .)

Independent research groups have so far failed to confirm the results of Taleyarkhan’s group, and controversy has dogged him. Some have criticized the experiments. Others have leveled charges of misconduct. Purdue convened two successive investigations in 2006 and 2007 to explore those allegations. Neither investigation charged Taleyarkhan with wrongdoing.

Still, questions lingered. Even the subcommittee on investigations and oversight of the House Committee on Science and Technology weighed in, criticizing what it regarded as a limited investigation by Purdue. (See Physics Today, June 2007, page 36 .) The university established a third investigation in November 2007. In its 18 July report to Purdue, the investigation committee charged Taleyarkhan with misconduct relating to the authorship of a scientific paper and to the characterization of a certain experiment as an “independent” confirmation of bubble fusion.

One of the sonoluminescence experts whose group has not been able to reproduce Taleyarkhan’s bubble nuclear fusion results is Kenneth Suslick of the University of Illinois at Urbana-Champaign. He regrets that the investigations did not look into how the science experiments were conducted, commenting that “justice has been done, but not completely.”

For his part, Taleyarkhan commented by e-mail that “there is much more to this story than meets the eye, and the full truth will have to come out soon.”

The investigation committee was chaired by Purdue’s Mark Hermodson, a biochemist. Its six members included three researchers from other universities and one from a national lab. The committee considered 12 allegations and found sufficient evidence to cite Taleyarkhan with research misconduct in two cases.

Both cases deal with the publication of results from an experiment in which Taleyarkhan had been “heavily involved,” according to the committee. The research paper was originally submitted to (and rejected by) Physical Review Letters with Yiban Xu, a postdoctoral fellow, as the sole author. Despite Taleyarkhan’s apparent involvement, the committee concluded that a senior mentor may choose not to have his name appear as an author of a publication for a number of legitimate reasons. The PRL reviewer commented that with only one author, the needed cross checks and witnessing of results seemed lacking. Subsequently, the committee reports, “Taleyarkhan with falsifying intent caused” Adam Butt, a master’s student of Taleyarkhan’s, to be added to the paper as a coauthor. In his statement, Butt asserted that his only contribution was to check that data had been correctly transferred from a spreadsheet and to suggest some minor editorial changes to the manuscript. The paper, with Xu and Butt as coauthors, was published in Nuclear Engineering and Design in 2005. The investigation committee concluded that Taleyarkhan had compelled the addition of Butt’s name to create an appearance of collaboration between Xu and Butt.

The second instance of misconduct cited by the committee concerned a paper published by Taleyarkhan and his colleagues in PRL in 2006, in which they asserted that their 2002 observations of bubble fusion “have now been independently confirmed.” The independent confirmation cited was the 2005 Nuclear Engineering and Design paper by Xu and Butt. The committee stated that “Dr. Taleyarkhan himself well knew the degree of his direct mentoring, editing and promotion of Dr. Xu’s work and the resulting publication.” It concluded that the effort to characterize Xu’s experiment as “independent” was research misconduct.

Taleyarkhan appealed the investigation’s findings but on 21 August the university’s appeal committee concluded that the committee had followed due process and had an evidentiary basis for its conclusions.