John Clarke | |
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Clarke in 2025 | |
| Born | (1942-02-10)10 February 1942 (age 83) Cambridge, England, UK |
| Education | Perse School |
| Alma mater | |
| Known for | |
| Awards |
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| Scientific career | |
| Fields | Condensed matter physics |
| Institutions | University of California, Berkeley (1969–2010) |
| Doctoral advisor | Brian Pippard |
| Doctoral students | John M. Martinis (1985) |
John Clarke (born 10 February 1942) is a Britishexperimental physicist and Professor Emeritus at theUniversity of California, Berkeley.[1] He is known for his various works on measurement devices based onsuperconductivity.Steven Girvin has called Clarke "the godfather of superconducting electronics".[2]
In the 1980s, Clarke led a research team, that includedJohn M. Martinis andMichel Devoret.[3] Their discoveries inmacroscopic quantum phenomena using theJosephson effect earned them theNobel Prize in Physics in 2025.[3]
John Clarke was born on 10 February 1942 inCambridge, England.[4][5] He attended thePerse School, before embarking on aNatural Sciences degree atChrist's College,Cambridge.[6] He graduated with aB.A. in Physics in 1964, and then studied for aPh.D. in Physics in theRoyal Society Mond Laboratory at theUniversity of Cambridge.[7]
In 1965, Clarke became one of the first students to enter the newly foundedDarwin College, Cambridge, and was the first president of the Darwin College students' association.[8] While conducting his doctoral work—which was supervised byBrian Pippard—Clarke developed a very sensitivevoltmeter, which he later called "SLUG" (Superconducting Low-inductance Undulatory Galvanometer).[6][7] He obtained his doctorate in 1968.[7] Clarke has said at various times that his work was influenced by Nobel laureateBrian Josephson, who predicted theJosephson effect in 1962 and was also a previous student of Pippard.[9][10]
After completing his doctorate, Clarke gained a postdoctoral research position at theUniversity of California, Berkeley, and subsequently worked at Berkeley for his whole academic career, as Assistant Professor (1969), Associate Professor (1971), and as Professor of Physics (1973–2010).[11] In 1969, Clarke also joinedLawrence Berkeley National Laboratory, eventually retiring as a faculty senior scientist in the Materials Sciences Division in 2010.[12]
Clarke's association with the University of Cambridge continued, after he moved to the United States.[11] In 1972, he was elected a Fellow of Christ's College; in 1989, he was a visiting fellow atClare Hall, Cambridge, and in 1998 was elected a by-fellow ofChurchill College, Cambridgeand as Professor of Physics (1973–2010).[11] Clarke was awarded aD.Sc. from the University of Cambridge in 2003.[11] He was elected an Honorary Fellow of Christ's College in 1997, and of Darwin College in 2023.[11]
Clarke's research focuses onsuperconductivity and superconducting electronics, particularly in the development and application ofsuperconducting quantum interference devices (SQUIDs), which are ultrasensitive detectors ofmagnetic flux.[13][14][15]
In 1985, Clarke,John M. Martinis (his Ph.D. student), andMichel Devoret (a postdoctoral researcher at the time) demonstrated the quantum behaviour of aJosephson junction.[3][16] They showed that at low temperature, a macroscopic electronic state associated with superconductors underwentquantum tunnelling at zero voltage.[17] The same year, by sendingmicrowave pulses of the system, theresonances showed quantised energy levels.[18] This experiment was the first evidence ofcircuit quantum electrodynamics, that would become later the basis forsuperconducting quantum computing.[19][20] The work, which was recognized with theNobel Prize in Physics in 2025, was largely funded by the Office of Basic Energy Sciences in theUnited States Department of Energy.[21]
Clarke has also worked in the application of SQUIDs configured as quantum-noise limited amplifiers to search for theaxion, a possible component ofdark matter.[13]
Clarke obtained anAlfred P. Sloan fellowship (1970)[22] and aGuggenheim Fellowship (1977).[23] Clarke was elected aFellow of the Royal Society in 1986.[13] He was awarded theJoseph F. Keithley Award For Advances in Measurement Science in 1998,[24]Comstock Prize in Physics in 1999[25], theHughes Medal[13] and the Olli V. Lounasmaa Memorial Prize in 2004.[26] He was elected a Foreign Associate of theNational Academy of Sciences in May 2012.[27] He was elected to theAmerican Philosophical Society in 2017.[28]
In 2021, theMicius Quantum Prize was jointly awarded to Clarke,Michel Devoret andYasunobu Nakamura.[29]
Clarke, Michel Devoret, andJohn M. Martinis were jointly awarded the 2025Nobel Prize in Physics "for the discovery of macroscopicquantum mechanical tunnelling and energy quantisation in an electric circuit".[30]