J. Michael Kosterlitz

Son of a refugee from Nazi Berlin, he used topology to explain how ultra-thin films change state, opening a new field of physics.

The Nobel citation: “for theoretical discoveries of topological phase transitions and topological phases of matter”

Born: June 22, 1943, Aberdeen, United Kingdom
Shared with: David J. Thouless, F. Duncan M. Haldane
Affiliation at the time: Brown University, USA

Physics prize

2016

Shared with 2 other laureates.

Age that year

73years

Born in 1943.

Sources cited

Fact-checked September 24, 2026.

He found his Nobel problem by accident: after rivals, including a Berkeley group, beat him to results three times, he went door to door and found David Thouless.
A missed CERN application deadline sent him to Birmingham, a city he did not want to live in, where he began the work with Thouless.
In his twenties he was, by his own account, one of Britain's best climbers. A route he created in Italy's Orco Valley, Fessura Kosterlitz, went unrepeated for a decade.
His father fled Nazi Berlin in 1934 and later co-discovered the enkephalins, the body's own painkillers. Father and son were both elected Fellows of the Royal Society.
Diagnosed with multiple sclerosis in 1978, he kept working and published nearly sixty papers after moving to Brown University.

The breakthrough

The Kosterlitz-Thouless transition: vortex pairs that unbind (1972-1974)

In the early 1970s, most physicists believed that a flat, two-dimensional layer of matter, such as a film of liquid helium only a few atoms thick, could never settle into an ordered state like superfluidity, where a liquid flows with no friction at all. Mathematical arguments showed that the random jiggling of heat destroys long-range order in two dimensions. Working in Birmingham in 1972 and 1973, Kosterlitz and David Thouless found the loophole. They focused on vortices, tiny whirlpools in the film. Each vortex winds a whole number of turns that cannot be smoothed away, which makes it a topological feature. At low temperatures, vortices appear only in tight pairs spinning in opposite directions, so their effects cancel and the film keeps a subtler kind of order. At a sharp critical temperature, the pairs tear apart, lone vortices roam freely, and the order collapses. Picture a crowded dance floor: while couples spin holding hands, the crowd flows smoothly, but once partners let go and whirl off alone, the floor turns to chaos. In 1974 Kosterlitz worked out the detailed mathematics of this unbinding. In 1977 he and David Nelson predicted that a film's superfluid density should jump from zero to a value fixed only by the transition temperature and constants of nature. Experiments on helium films confirmed the jump in 1978. The same theory applies to thin superconductors, magnetic films and melting two-dimensional crystals.^{[2],[3],[5],[6],[7]}

“very occasionally, being ignorant of the fact that a problem is insoluble, allows one to proceed and solve it anyway.”

J. Michael Kosterlitz, From his Nobel Lecture, 'Topological Defects and Phase Transitions', Stockholm, 8 December 2016, on why he pressed ahead with a problem that the conventional wisdom of the early 1970s said had no solution.^[3]

What it meant for humanity

Kosterlitz's work changed how physicists understand matter rather than producing a device or a cure. Before 1972, many experts thought two-dimensional materials could not have true phase transitions at all. The Kosterlitz-Thouless theory showed that they can, through a new kind of transition driven by topological defects that breaks no symmetry, and it made sharp predictions that experiments could test. In 1978 David Bishop and John Reppy measured superfluid helium films spread over a spiral of plastic and found the jump that Nelson and Kosterlitz had predicted. Data from several other groups, some of it plotted before the experimenters knew of the prediction, agreed. Since then the theory has explained experiments on thin superconducting films, arrays of Josephson junctions, superconducting wire networks, the melting of two-dimensional crystals and colloids, and layers of ultracold atoms. It also brought topology, the mathematics of properties that change only in whole-number steps, into the study of states of matter. Extended by Thouless and Haldane, that idea grew into the study of topological insulators and topological superconductors. The Nobel committee noted hopes that such materials could lead to new electronics, better superconductors and future quantum computers, but those uses remain hopes, not products. Kosterlitz's life carries a human lesson too. At 35 he was diagnosed with multiple sclerosis, fell into a depression that lasted several years, and kept working. In his Nobel autobiography he tells young scientists that illness or other setbacks need not stop them from succeeding.

In 1978 Bishop and Reppy measured a sudden jump in the superfluid density of thin helium films that matched the universal value Nelson and Kosterlitz had predicted the year before.^[3],[6]
The theory has explained experiments on thin superconducting films, arrays of superconducting tunnel junctions, superconducting wire networks and the melting of two-dimensional solids.^[6]
In 2006 experimenters observed the transition in a layered gas of ultracold atoms, with free vortices appearing at higher temperatures, just as the theory describes.^[3],[6]
Fellow Brown laureate Leon Cooper said in 2016 that the theory had laid the foundation of the entire field and had been cited more than 6,600 times.^[7]
The Nobel committee called the transition one of the twentieth century's most important discoveries in condensed matter theory, and noted hopes that topological materials could serve future electronics and quantum computers.^[4],[5]

Impact in numbers

Kosterlitz's contribution is to understanding, so we record no quantified claims. The Kosterlitz-Thouless theory showed that flat, two-dimensional systems can undergo a new, topological kind of phase transition, and it gave exact predictions that experiments on helium films, superconducting films, Josephson-junction arrays, two-dimensional crystals and ultracold atoms have borne out. It became a founding example of topology in condensed matter physics, a field that now includes topological insulators and research toward topological quantum computers. None of this has yet produced lives saved, people fed or revenue that could honestly be credited to a 1972 theory. The practical hopes named by the Nobel committee are still hopes, and any future devices will owe far more to later theorists, experimenters and engineers. We record no harm claim either, because we found no damaging use of the work. Its value lies in what it changed about what physicists believe is possible in low-dimensional matter.

Fundamental science

No number is given here on purpose. Some contributions cannot be counted honestly, and we would rather describe them than invent a figure.

The double edge

We found no documented harm from Kosterlitz's work, which is theoretical and has no military or damaging use that we could trace. The one controversy is about credit. The Soviet physicist Vadim Berezinskii published related ideas in 1970 and 1971, a year before Kosterlitz and Thouless, and the transition is often called the BKT transition in his honour. The Nobel committee's scientific background says Berezinskii saw that vortices could drive a phase transition but did not correctly describe its nature. He died in 1980, long before the prize. Kosterlitz has said that he and Thouless did not know of Berezinskii's work at the time, and that for some reason their own work received much more attention.

Minor
Credit for Vadim Berezinskii
Berezinskii, working in Moscow, recognised a year earlier that vortices could drive a transition in two dimensions. He died in 1980 and did not share the 2016 prize. The Nobel committee credits Kosterlitz and Thouless with describing the transition correctly, while Kosterlitz himself acknowledges that Berezinskii's work received far less attention.^[3],[5],[6]

Against the odds

Kosterlitz himself grew up safe in Scotland. The persecution in his story fell on his father's generation. Hans Kosterlitz, a young doctor and researcher at Berlin's Charité hospital, came from a Jewish family, though he did not practise the religion. After Hitler took power in 1933, new laws pushed Jews out of state service, sharply curtailed Jewish doctors and restricted their payment from public health insurance. Michael Kosterlitz writes that his father could no longer be paid as a doctor in Berlin or marry his non-Jewish fiancée, Hanna Gresshöner; in 1935 the Nuremberg Laws formally banned such marriages. Hans wrote to J.J.R. Macleod in Aberdeen, who found modest funding but no promise of a secure job, and he arrived in March 1934. Hanna followed, and they married in Britain. Hans's parents and younger brother reached Britain in 1939, a year in which about 77,000 Jews left Germany and Austria; the vast majority of Jews still in Germany in late 1941 were murdered in the Holocaust. Michael was born in wartime Aberdeen in 1943. His parents wanted nothing to do with Germany and spoke English at home, and he was raised a nominal Christian, for years unaware of his Jewish roots. We found no record of antisemitism directed at him. His hardest personal obstacle came later: multiple sclerosis, diagnosed in 1978.

1933
Dismissal
After the Nazi takeover, his father, from a Jewish family, could no longer be paid as a doctor in Berlin, according to Kosterlitz. That year's laws excluded Jews from state service and curtailed Jewish doctors.^{[2],[10],[11]}
1934
Exile
His father left Germany and arrived in Aberdeen in March 1934 on modest funding arranged by J.J.R. Macleod, with no guarantee of a secure job. His mother followed so that they could marry.^[2],[9],[10]
1935
Discrimination
Kosterlitz writes that his father was forbidden to marry a non-Jewish woman such as his mother. The Nuremberg Laws of September 1935 formally banned marriages between Jews and non-Jewish Germans.^[2],[13]
1939
Exile
His paternal grandparents, Bernhard and Selma Kosterlitz, and his uncle Rolf moved to Britain in 1939, when tens of thousands of Jews were leaving Nazi Germany and annexed Austria.^[10],[12]
1978
Other
In September 1978, aged 35, he was diagnosed with multiple sclerosis. He writes that it plunged him into a depression lasting several years, seemed to end his mountaineering and slowed his physics for a time.^[2]

What Jews faced around 2016

Open borders and a rising tide of attacks

With the Soviet Union gone, about 1 million emigrants from the former USSR eventually settled in Israel and 300,000 had reached the United States by 2000, and Syria let its last Jews leave in 1992. Terrorism against Jewish targets continued: bombings in Buenos Aires killed 29 at Israel's embassy in 1992 and 85 at the AMIA community center in 1994, and synagogues were attacked in Djerba in 2002 and Istanbul in 2003. About 1,000 Israelis were killed during the Second Intifada of 2000 to 2005, many in suicide bombings.

2015Hypercacher kosher supermarket siege. Days after the Charlie Hebdo shooting, a gunman who had pledged allegiance to the Islamic State attacked the Hypercacher kosher supermarket in eastern Paris, murdering four Jewish hostages and holding others captive until police stormed the store.
2015Copenhagen synagogue shooting. Hours after attacking a free-speech event, a gunman shot Dan Uzan, a 37-year-old Jewish volunteer guarding a bat mitzvah celebration at Copenhagen's Great Synagogue. Uzan died of his wounds.
2014Jewish Museum of Belgium shooting. A gunman who had spent more than a year in Syria opened fire at the Jewish Museum of Belgium in Brussels, killing four people. It is considered the first attack by the Islamic State in Europe.

The full timeline

Jewish background

Jewish fatherDistant from Jewish identity

His father, Hans Kosterlitz, a Berlin-born biochemist who later co-discovered the enkephalins, the body's own painkillers, came from a Jewish family but did not practise the religion. His mother, Johanna (Hanna) Gresshöner, came from a conventional Christian German family and was devout. Kosterlitz writes that he was raised as a British child and a nominal churchgoing Christian, and for several years did not know he was of German Jewish origin or what being Jewish meant. At Cambridge he dropped religion altogether and describes himself as an atheist.^{[2],[9],[10],[14]}

Key dates

1934
His father, Hans Kosterlitz, leaves Nazi Berlin for a post at the University of Aberdeen.^[2],[10]
June 22, 1943
Born in wartime Aberdeen, Scotland.^[1],[2]
1961
Enters Gonville and Caius College, Cambridge, on a major scholarship in natural sciences; graduates with a BA in 1965.^[2],[8]
1969
Earns an Oxford DPhil in high-energy physics, then takes a postdoctoral post in Turin, where he creates a climb that bears his name, Fessura Kosterlitz.^[1],[2]
1970
Marries Berit in Turin and joins Birmingham University as a research fellow, a job he took after missing a CERN application deadline.^[2],[3],[8]
1972
After rival groups, including one at Berkeley, beat him to results three times, he turns to David Thouless's problems; their first paper on topological phase transitions appears.^[2],[6]
1974
Publishes his renormalization-group treatment of the transition and, after a year at Cornell, returns to Birmingham as a lecturer.^[2],[6]
1977
With David Nelson, predicts a universal jump in the superfluid density of thin films; Bishop and Reppy confirm it in 1978.^[2],[3],[6]
September 1978
Diagnosed with multiple sclerosis.^[2]
1982
Joins Brown University in Providence, Rhode Island, as a professor of physics.^[1],[2],[7]
2000
Receives the American Physical Society's Lars Onsager Prize.^[7]
2004
Becomes a US citizen while keeping his British citizenship.^[2]
October 4, 2016
Awarded the Nobel Prize in Physics, sharing half with Duncan Haldane; David Thouless receives the other half.^[1],[4]
2026
Elected a Fellow of the Royal Society, as his father had been in 1978.^[10],[15]

Sources

1.J. Michael Kosterlitz – Facts · NobelPrize.org (Nobel Prize Outreach), 2016
2.J. Michael Kosterlitz – Biographical · NobelPrize.org (Nobel Prize Outreach), 2016
3.Topological Defects and Phase Transitions (Nobel Lecture, 8 December 2016) · The Nobel Foundation, 2016
4.Press release: The Nobel Prize in Physics 2016 · The Royal Swedish Academy of Sciences (NobelPrize.org), 2016
5.Popular information: Strange phenomena in matter's flatlands · The Royal Swedish Academy of Sciences (NobelPrize.org), 2016
6.Scientific Background on the Nobel Prize in Physics 2016: Topological Phase Transitions and Topological Phases of Matter · Class for Physics of the Royal Swedish Academy of Sciences, 2016
7.Brown's J. Michael Kosterlitz wins Nobel Prize in Physics · Brown University, 2016
8.Two former Birmingham scientists awarded Nobel Prize for Physics · University of Birmingham, 2016
9.Son of famous scientist helps launch Kosterlitz Centre · University of Aberdeen, 2010
10.Hans Kosterlitz · Wikipedia
11.Anti-Jewish Legislation in Prewar Germany · United States Holocaust Memorial Museum, Holocaust Encyclopedia
12.German Jewish Refugees, 1933–1939 · United States Holocaust Memorial Museum, Holocaust Encyclopedia
13.The Nuremberg Race Laws · United States Holocaust Memorial Museum, Holocaust Encyclopedia
14.Jewish Nobel Prize Winners in Physics · JINFO.ORG
15.Exceptional scientists elected as Fellows of the Royal Society · The Royal Society, 2026

Fact-checked on September 24, 2026 by a separate AI fact-checking pass that re-opened the sources, with 2 corrections made. How we check

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