Distinguished Professor George Pickett, FRS, who has died aged 85, left enduring marks on the fields of ultralow temperature physics and quantum fluids at the highest international levels.
He was renowned for his remarkable practical sense, profound physical intuition, and an innate scientific expediency, qualities which enabled him to develop one of the world’s leading laboratories at Lancaster University and, for a time, the coldest temperature on Earth. Throughout his exceptional scientific career, Pickett was on the quest to reach the lowest temperatures in order to minimize the thermal motion of atoms and reveal the subtle nature of quantum mechanics and associated phenomena, such as lossless transport of electricity in superconductors and the resistance-free flow of liquids in superfluids.
Pickett was born on 10 April 1939. He received his education at Bedford Modern School and Magdalen College, Oxford, where he earned his BA in 1961 and his DPhil degree at the Clarendon Laboratory. Early low-temperature measurements at Oxford were followed by groundbreaking investigations at Helsinki University of Technology in Finland, where he studied phase separation of helium-3 and helium-4 mixtures and their transition from an ordinary liquid to a superfluid. This work laid a foundation for the following revolutionization of cooling techniques at Lancaster, where he devoted his career to transforming the field of low-temperature physics.
Pickett joined Lancaster University as a Senior Visiting Fellow on 1 August 1970, and quickly advanced through the ranks, becoming Reader in 1983, the holder of a personal chair in 1988, and subsequently Distinguished Professor. Pickett’s group substantially contributed to the excellent outcomes of Lancaster physics in successive Research Assessment Exercise and Research Excellence Framework results.
At Lancaster, Pickett developed world record–holding 3He–4He dilution refrigerators capable of continuously delivering temperatures lower than two thousandths of a degree above absolute zero. These advanced refrigerators are essential for applications in quantum technology and for pre-cooling nuclear demagnetization stages to attain extreme ultralow temperatures. His work also included the construction of specialist laboratories designed to minimize noise and vibration. The success of his research group was enhanced by an exceptional research technician, the late Ian Miller, whom Pickett made sure received both institutional and national recognition.
Together with the late Tony Guénault, Pickett pioneered a novel form of nuclear refrigeration using finely divided copper immersed in liquid 3He. Their method represented a paradigm shift from prevailing trends, as they focused on minimizing heat leaks while using only the essential amount of nuclear refrigerant. These innovations led to some of the lowest temperatures ever achieved in pure 3He, isotopic solutions, and metals, laying the foundation for the world-leading research conducted by a tight-knit group of Lancaster academics, including the late Shaun Fisher.
Pickett’s work enabled the exploration of extreme temperatures, revealing the dynamics of ballistic 3He quasiparticles and superfluid phase transitions. He was an early advocate for experiments that simulated early-universe phenomena in the laboratory.
One such experiment was famously described as “the Big Bang in a drop of helium” and resulted in a landmark article in Nature. In 1996, the Nobel Prize winner David Lee specifically referenced Pickett and his research group's contributions to 3He studies. Pickett’s numerous publications included 7 articles in Nature, 3 in Nature Physics, and 35 in Physical Review Letters.
Pickett’s passion and talent for communicating in languages other than English facilitated productive collaborations with leading research groups. Finnish, Danish, and Swedish all seemed to come naturally to him, and even the Slavic languages were no problem. He learned Russian to be able to give presentations when he visited laboratories in the former Soviet Union. Pickett was instrumental in initiating the European Microkelvin projects, uniting Europe’s ultralow temperature laboratories, and played a pivotal role in establishing the European Cryocourse cryogenics training schools.
In recognition of his many international collaborations and outstanding scientific achievements, Pickett was elected a member of the Finnish Academy of Science and Letters in 1988.
He was elected as a Fellow of the Royal Society in 1997, and with Guénault, he received the Simon Memorial Prize in 1998. Pickett was made a foreign member of the Russian Academy of Sciences in 2006, an Honorary Fellow of Lancaster in 2009, and was awarded an honorary degree by the Slovak Academy of Sciences in Košice in 2023.
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