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.
