BioEd Online

Werner Marx and Andreas Barth have decided to revise their recently published paper on the future of high-temperature superconductivity research after complaints about their ominous conclusions. They stand by their data, they say, but add that some things could perhaps have been better phrased.

The paper by the two German information scientists looks at the dramatic decline in this field since its heyday in the 1980s, as an exercise in identifying insights that can be gained from data mining. Their paper included a graph of research into cuprates, a commonly studied high-temperature superconductor, in which one subtype slides down to nearly zero papers and patents per year by 2005, and the others show similar dramatic drops. "From extrapolation to zero it may be estimated that research concerning cuprate superconductors will end between 2010 and 2015 if no groundbreaking discoveries will happen to occur," they wrote.¹

That intriguing notion spurred a News item in Nature (see ' Superconductivity research is down but not out') and anger among some superconductivity researchers, who did not like the prediction of the demise of their research field. There was some "heavy leaning on them" by superconductivity physicists, says Paul Grant, a visiting scholar at Stanford University in California who heard about the change.

The paper has caused such a furore that Marx and Barth, respectively of the Max Planck Institute for Solid State Research in Stuttgart and FIZ Karlsruhe, Germany, have felt moved to publish an altered version.² The controversial extrapolation statement is now noticeably absent.

"The wording 'extrapolation to zero' was misleading and has been misinterpreted by some people," says Marx. "We intended to say: if the decrease continues as in the past 15 years or so, basic research on cuprates would end around 2010-15." They emphasize that they are only making an observation about numbers, rather than a prediction about the field.

In a new graph in the altered version, the number of papers and patents of some types of cuprate have been multiplied by ten so that patterns can be better seen and in this version the line no longer looks as if it drops right down to the baseline.

"It was not our intention to forecast or predict the death of the entire research discipline," Marx adds. The revised version of the paper now says: "Due to the absence of a satisfactory theoretical explanation of the phenomenon, a considerable amount of research can be expected also in the future."

Don't forget applied research

Marx and Barth note that their literature analysis focused on basic research in chemistry and physics, and not on engineering and technology. "The more applied the work is, the more incomplete is the coverage in literature databases," they admit. "We received some criticism from a few people working in applied research and engineering," Marx adds.

Gordon Donaldson of the physics department at the University of Strathclyde, UK, and honorary editor of the journal Superconductor Science and Technology, includes himself in the critical camp.

In a strict sense, the original conclusions are right, says Donaldson, but the applied nature of current research cannot be ignored. "I dare say that not many academic publications on the internal-combustion engine appear now, but that neither means that cars have vanished from the Earth nor that do-it-yourself books on engines go unwritten."

The fuss surrounding Marx and Barth's paper is "nonsensical", says Jan Zaanen of Leiden University in the Netherlands. Physicists will continue to chip away at what Zaanen describes as one of physics' "big mysteries" until they find the next superconductor that can conduct at high temperature.

Marx stands by the facts of the paper. "The data and the conclusions concerning the significant decrease of basic-research publication output (activity) around cuprate high-temperature superconductors between 1985 and 2006 remain the same," he says. But, he adds: "We are no prophets, and science is no linear process."

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