Refugee parents in Aberdeen
John Michael Kosterlitz was born on June 22, 1943, in wartime Aberdeen, Scotland. His father, Hans Walter Kosterlitz, was a doctor and biochemist from a Jewish family in Berlin. Under Nazi rule he was forbidden to marry his fiancée, Johanna Maria Gresshöner, who came from a conventional Christian German family, and forbidden to be paid as a doctor. In 1934 he accepted a lectureship at the University of Aberdeen and left Germany; Johanna followed him so that they could marry, which they did in Glasgow.
Hans Kosterlitz went on to become one of Britain’s most distinguished pharmacologists. In 1975, with John Hughes, he discovered the enkephalins, the brain’s own opioid molecules, a landmark in understanding pain, and he kept working into his nineties. The University of Aberdeen’s Kosterlitz Centre is named after him. Michael later wrote that he followed his father’s dictum: work hard and play hard.
Michael’s mother came from a German Christian family, and photographs in his Nobel autobiography show him in Scotland in 1961 with his mother and his paternal grandmother, who lived to ninety-two. His father refused to stop working until he was over ninety, and Michael, still doing research in his seventies, has compared himself to him in that respect.
Growing up British
Michael grew up in Cults, then a village outside Aberdeen, as an ordinary British child. His parents wanted nothing to do with Germany and spoke only English at home, using German as a secret language when they did not want him to understand. For years he did not know that he was of German Jewish origin, or even what being Jewish meant; the only thing he knew, he recalled, was that a classmate got extra holidays for his Jewish religion, which made the whole class want to convert. His father had no interest in religion, and his mother, a devout Christian, took him to church. When he left for university he dropped religion with relief and has described himself ever since as an atheist.
He was educated at Robert Gordon’s College in Aberdeen and then at the Edinburgh Academy, where he found that his talent for logical deduction made up for what he called an unreliable memory. Chemistry was his favourite subject until he discovered he was red-green colour blind and could not tell his test tubes apart. Physics, which let him deduce answers rather than memorise them, became his field.
A climber who did physics
In 1961 Kosterlitz won a major scholarship to Gonville and Caius College, Cambridge. There he discovered rock climbing, which he said quickly became like a drug. Weekends were spent racing to North Wales, the Lake District or the Scottish mountains, and his studies suffered; he graduated with an upper second. He did a further year of mathematics at Cambridge and then a doctorate in high-energy theory at Oxford, finished in 1969, while sharing a house with medical students and his future wife, Berit, a Swede.
In the 1960s and 1970s he was one of the best climbers in Britain. A postdoctoral year in Turin, chosen partly for its closeness to the Alps, produced a climb in the Orco Valley still known as the Fessura Kosterlitz, and he is credited with helping to start the “Nuovo Mattino” movement in Italian free climbing. He made the first repeat of the American Direct on the Petit Dru above Chamonix. He seriously considered becoming a professional mountaineer before deciding that an academic career would leave enough holidays for the mountains. He and Berit married in Turin in 1970.
The office next door
In 1970 Kosterlitz took a research fellowship at the University of Birmingham, still working on the forerunners of string theory. Three times a group in Berkeley published the calculation he was about to finish. Frustrated, he went from office to office asking colleagues if they had a problem he could help with, and ended up in the office of David Thouless, who talked to him about superfluid helium films, two-dimensional crystals, vortices and topology. None of it was familiar. All of it made sense to him.
Physicists at the time believed that in a perfectly flat, two-dimensional world, random thermal jiggling would destroy any kind of order, so that thin films could never undergo a true phase transition like water freezing into ice. Yet experiments on thin films of helium seemed to show superfluidity. Kosterlitz and Thouless found the answer in tiny whirlpools, or vortices. At low temperature the vortices exist only in tightly bound pairs that spin in opposite directions and cancel each other out. Above a certain temperature the pairs suddenly unbind and the vortices wander freely, destroying the ordered state. The transition depends not on symmetry, as ordinary phase transitions do, but on topology, the mathematics of properties that change only in whole steps. They published the theory in 1972 and 1973; the Soviet physicist Vadim Berezinskii had reached similar ideas independently, and it is now called the Berezinskii–Kosterlitz–Thouless, or BKT, transition.
The Nobel committee later noted, with some amusement, that the two men took on the problem of phase transitions in flat materials, in their own words, Thouless out of curiosity and Kosterlitz out of ignorance: as a particle physicist he did not know that the experts considered the question settled.
Theory meets experiment
Kosterlitz spent six months reading a single paper on the renormalization group, then a new method for studying phase transitions, until he could reproduce every step, and used it to give an exact treatment of the transition in 1974. After a year at Cornell with Michael Fisher and the young David Nelson, he returned to Birmingham as a lecturer. In 1977 Nelson and Kosterlitz predicted that the density of a two-dimensional superfluid should jump by a universal amount at the transition. The next year experiments on helium films confirmed it. Nothing, he wrote, would ever compare to the exhilaration of that moment when theory agreed quantitatively with experiment.
The BKT transition proved to be universal. It describes thin superconducting films, arrays of tiny superconducting junctions, magnetic layers, the melting of two-dimensional crystals and clouds of ultracold atoms. In 2016 the Nobel Prize in Physics went half to Thouless and half to Duncan Haldane and Kosterlitz “for theoretical discoveries of topological phase transitions and topological phases of matter.” The Nobel committee called the BKT transition one of the twentieth century’s most important discoveries in the theory of condensed matter physics.
Why topology matters
The idea that topology could govern the behaviour of matter, first shown by Kosterlitz and Thouless, grew into one of the most active fields in modern physics. It explained the astonishingly precise steps of the quantum Hall effect, now used to define electrical resistance standards worldwide, and led to the discovery of topological insulators, topological superconductors and other new materials whose properties are protected against disorder and defects.
These topological materials are being studied around the world for low-power electronics and for quantum computers whose bits would be protected from errors by topology itself. Many of these applications are still in development, and the Nobel committee spoke of hope rather than finished products. But the conceptual tools Kosterlitz helped to create are now standard equipment for physicists and materials scientists designing the next generation of electronic devices.
Illness and a new life at Brown
In September 1978, aged 35, Kosterlitz woke up unable to stand. He was diagnosed with multiple sclerosis. Believing his climbing life was over, he fell into a depression that lasted several years, and his research slowed. A neurologist told him that after twenty-five years he would know how bad his case was. In 1982 he moved to Brown University in Providence, Rhode Island, where he has been a professor ever since; he and Berit became American citizens in 2004.
At Brown he studied arrays of Josephson junctions, disordered superconductors, spin glasses, crystal growth and the numerical detection of phase transitions, collaborating for decades with colleagues in Brazil, Finland, Canada and Korea. At 55 he entered a trial of a new MS drug and had no further attacks. He used his Nobel autobiography to encourage young scientists facing illness not to give up.
Jewish heritage
Kosterlitz has a Jewish father and a Christian mother, and he is not religious. His family story is nonetheless shaped by the persecution of German Jews: his father’s career in Berlin was ended by the Nazis because he came from a Jewish family, and his parents could not legally marry in Germany. Their emigration to Scotland in 1934 is the reason he was born in Aberdeen.
He has written frankly that as a child he did not know of his German Jewish origins. He is listed among Jewish Nobel laureates on the strength of his father’s heritage, and Wikipedia describes his parents as German-Jewish émigrés.
Family and legacy
Kosterlitz and Berit have three children, Karin, Jonathan and Elisabeth, and five grandchildren, and they spend part of every summer at their house in Sweden. Since 2016 he has also been a distinguished professor at the Korea Institute for Advanced Study in Seoul. He was elected a Fellow of the Royal Society in 2026.
His legacy began with a lucky accident: a missed job application, a run of bad luck in string theory and a conversation in the office down the hall. From it came the discovery that the shape of mathematics, not just the arrangement of atoms, can decide how matter behaves. That insight now guides the search for new quantum materials and more robust electronics.
Sources & further reading
J. Michael Kosterlitz, Biographical, NobelPrize.org · The Nobel Prize in Physics 2016, Popular information, NobelPrize.org · J. Michael Kosterlitz, Facts, NobelPrize.org · J. Michael Kosterlitz, Wikipedia · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.