NZ links in research

New Zealand researchers have won international recognition for helping uncover a mechanism believed to have been important in the formation of the universe after the Big Bang.

They detected miniature whirlpools in super-cold droplets, in which the individual identities of millions of atoms blurred to a point where they behaved as a single particle.

"I think it's a great outcome in this field," said physicist Dr Ashton Bradley, a research fellow at the University of Otago's Jack Dodd Centre for Quantum Technology, in an interview at the end of last week.

Dr Bradley was one author of a report published last week in the latest edition of the international scientific journal Nature.

Several scientists with strong New Zealand links were involved with the research undertaken by experimental physicists from the University of Arizona and by two theoretical physicists from the University of Queensland, Dr Bradley and Otago graduate Dr Matthew Davis.

Dr Bradley, born in Auckland, earned a doctorate from Victoria University, and left Queensland University for a fellowship at Otago University in June.

The scientific report draws on theoretical work by centre director Prof Crispin Gardiner, Otago physics head Prof Rob Ballagh and Dr Davis on the properties of Bose-Einstein condensates, a novel state of matter predicted in 1925.

It was predicted certain types of gas would stop behaving as a collection of individual particles if they were cooled to within a hair's breadth of absolute zero (-273.15degC).

In 1995, American researchers were first to create such a condensate, cooling rubidium gas until it developed bizarre, quantum properties.

In 1998, a team of Otago physicists also created the condensate at just above absolute zero.

Dr Bradley said the recent study had shown for the first time that vortices appeared spontaneously (about 25% to 50% of the time) in the condensate as it was being created, and did not have to be induced.

The research also enabled physicists to understand a little more about the behaviour of atoms in other phase transitions, such as the emergence of structures such as galaxies in the universe after the Big Bang.

Additional reporting by NZPA.


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