George Pickett obituary

Physicist whose work on nuclear refrigeration has aided understanding of the big bang and the early universe

Although absolute zero will for ever remain beyond our reach, we have achieved probably the next best thing." These were the words of George Pickett, who has died aged 85, discussing his work on nuclear refrigeration at Lancaster University, the purpose of which was to produce the lowest possible laboratory temperatures, a necessity for numerous scientific studies.

At such low temperatures - close to -273.15C, or what is known as absolute zero, the point at which an object has no heat at all - the motion of atoms and subatomic particles ceases almost completely. The rules of classical physics break down, allowing scientists to study the enigmatic world of quantum mechanics, determining how elementary particles move and interact.