Declan Butler The ArXiv preprint server — physicists’favourite place for early circulation of theirresults — has branched out into biology.

Last month, the server’s managers createdq-bio, an archive for quantitative biology. Themove reflects the fact that ArXiv’s traditionalconstituency of physicists, mathematiciansand computer scientists is increasinglyworking on biological problems, says itsfounder Paul Ginsparg of Cornell Universityin New York state.

The proportion of biology papers onArXiv has been growing steadily, reaching8% of the 4,500 submissions received lastyear. But until now, these papers have beenscattered across various subdisciplines onArXiv. The new arrangement will regroupexisting content, and provide a dedicatedarea for quantitative biology.

Ginsparg says he hopes that the move willhelp to “nucleate something for newcomers”from biological disciplines. The big test, hesays, will be whether biologists will followphysicists in being comfortable withcirculating their ‘big’ papers on the archiveprior to formal publication.

But papers on ArXiv are not peer-

reviewed, and there is concern this couldcreate problems if medical papers areaccessed by physicians or patients. Ginspargsays he is not really worried by this, addingthat the biology papers on the archive are“generally as uncontroversial as for physics”.

One of the few existing biomedicalpreprint servers — the BMJ ’s Netprints server— features a ‘health warning’ advising ‘casualreaders’ not to act on its contents. ArXiv hasno plans for such a warning, although anadvisory panel does screen submissions. ■

➧ arxiv.org

discovered,almost by accident, that helium-3could also become a superfluid, although at amuch lower temperature — about 1,000times lower than that needed for helium-4.This was difficult to explain,because helium-3 atoms belong to a class of particles known as fermions, which don’t like to share thesame quantum state. It was Leggett who, inthe 1970s, succeeded in explaining how this

Sarah Tomlin,LondonThree physicists who have wrestled with theexplanations behind intriguing quantumphenomena share this year’s Nobel Prize inPhysics.

Two Russians, Alexei Abrikosov of theArgonne National Laboratory in Illinois andVitaly Ginzburg,the retired head of the theorygroup at the P. N. Lebedev Physical Institute in Moscow, are rewarded for theirtheoretical explanation of a form of supercon-ductivity.Anthony Leggett of the University ofIllinois at Urbana-Champaign is recognizedfor his work on a type of superfluid.

A superfluid forms when a fluid, such asliquid helium, effectively loses all of its vis-cosity and flows without any resistance. Ifthat fluid is made up of electrons rather than atoms, the effect — electrical conduc-tivity without resistance — is called super-conductivity. Both phenomena dependupon all of the fluid’s constituent atoms or‘free’electrons dropping into the same quan-tum state — something that happens only atlow temperatures.

Superfluids are divided into more thanone type of material and behaviour. Theywere discovered in the 1930s, when helium-4was cooled to very low temperatures andbegan to flow without resistance. It was later

happens: the atoms first form into pairs,which then act like single particles that canoccupy the same quantum state.

Superconductivity had long been knownalso to depend on a similar pairing of elec-trons. But until Abrikosov and Ginzburg’stheory,building on work by a previous Nobelwinner, Lev Landau, theorists struggled toexplain the behaviour of a class of supercon-ductors, called ‘type II’, which can remainsuperconducting in the presence of a mag-netic field.

Their theory is now textbook material. Itis particularly important for understandingthe properties of superconducting magnets,such as those used in particle accelerators.“People use the Ginzburg–Landau theory all the time,” says Gil Lonzarich, a physicist at the University of Cambridge, UK. “I’mlooking at my board right now, and there is aGinzburg–Landau equation on it.”

Although the three theorists share similarinterests, says Lonzarich, they differ in theirapproach to research. Leggett is “an intuitivethinker”, says Lonzarich, whereas Abrikosovis a more formal mathematician. Hedescribes Ginzburg as one of those rare people who can do both formal and moreintuitive thinking.

The three theorists helped to change thefield of condensed-matter physics by recog-nizing the importance of interactionsbetween atoms or electrons — the behaviourof strongly interacting particles together canbe more important than individual particlebehaviour at the quantum level. This “led tomajor changes in thinking”, says Lonzarich,who argues that the recognition of the workby Abrikosov and Ginzburg, done in the1950s, is particularly long overdue. ■

The Nobel chemistry prize was announced after Nature went to press. For coverage see ➧ www.nature.com/nature

news

548 NATURE | VOL 425 | 9 OCTOBER 2003 | www.nature.com/nature

Super-cool theories secure physics prize

Members of the Nobel committee on physics announce this year’s prize recipients.

Biologists join physics preprint club

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© 2003 Nature Publishing Group