Sir Anthony Leggett, physicist who won the Nobel Prize for his research into superfluids – obituary

Explaining how the unwieldy Helium-3 atoms combined with each other posed a much harder challenge for theoretical physics, and it was Leggett who, working at Sussex University, succeeded in explaining how this occurs. The atoms, Leggett suggested, first form into pairs, which then act like single particles that can occupy the same quantum state.

Scientists find superfluids interesting because they behave in a similar way to superconductors – materials which lose all resistance to electricity when cooled below certain temperatures. The theory of superfluidity, though, has found wide-ranging applications as superfluid liquids can provide scientists with insights into the ways in which matter behaves in its lowest and most ordered state.

Recent studies have been concerned with examining how this order passes into chaos or turbulence – one of the unsolved problems of classical physics. Astronomers are also interested in superfluids because they may help to explain the behaviour of some of the more bizarre objects in the Universe. Neutron stars, the ultra-compact bodies left over when massive stars explode, are thought to have rotation properties similar to those seen in superfluids.

The field of superfluids and superconductivity is one of the most complex and, to the layman, baffling fields in science, yet Leggett came to it after giving up science at school as “incomprehensible” and taking an arts degree.