In the delightful accompanying memoir, Jan Hilgevoord describes the Institute for Theoretical Physics (ITFA) of the University of Amsterdam (UvA) during the 1950s. My aim is to repeat this exercise for the 1980s, combining some personal reminiscences with general observations.^[1] Of course, this still leaves huge gaps in the total story from 1950-2025, which I hope other people will fill in. Nonetheless, much of what Jan wrote also covers at least the spirit of the entire period until 1980, when the “old guard” was still around. The 1980s, then, were marked by a “change of the guard” I will try to describe in some detail.

Theoretical physics at the University of Amsterdam is often said to go back to Johannes Diderik van der Waals (1827-1923), who in 1877 was appointed as the first professor of physics at the UvA,^[2]  founded in the same year as a continuation of the Athenaeum Illustre originating in 1632. But the ITFA started only almost 75 years later, singlehandedly created by Jan de Boer (1911-2010), who was a professor at the UvA from 1946-1981. The second major figure in the history of the ITFA was Siegfried (“Sieg”) Wouthuysen (1916-1996), who was a lector and then a professor from 1949-1984. The third was Sybren de Groot (1916-1999), whose professorship ranged from 1964-1984. The fourth was Hilgevoord himself (1927-2025), who was lector and then a professor of theoretical physics from 1964-1987.^[3] There was a clear division between statistical physics (de Boer, de Groot) and high-energy physics (Wouthuysen, Hilgevoord—although the latter switched to the foundations of physics during the 1980s, see below).

I barely knew De Boer, but Hilgevoord describes him and his views on theoretical physics in detail—more about these views later. On the other hand, I got to know De Groot already when I was a schoolkid in my mid teens, since my mother (Joke Fehmers, 1931-2011) happened to know him. She was a journalist (for Algemeen Handelsblad), and besides his work as a theoretical physicist De Groot was also an editor of the literary magazine De Gids. Moreover, during the years that as an unmarried woman she rented a small apartment in a flat, he also had a pied-à-terre in the same corridor, for reasons that remain to be clarified. In any case, my interest in theoretical physics was already quite pronounced at the time, and so my mother introduced me to him, and he surely represented the kind of person I would like to become. Another ITFA contact I had before I entered University, again by chance, was with W.A. (Willem) van Leeuwen, a former PhD student of De Groot in his school on relativistic kinetic theory and co-author of the eponymous book.^[4] Van Leeuwen happened to live in an apartment in the same house as my maternal grandfather, who often saw him and for the same reason also introduced me to him. Willem showed me the ITFA, of which I also got a very good impression, as a place where people thought and taught, and studied the great questions of nature.

My interest in physics, by the way, seems to have come naturally, although throughout my teens it competed with an interest and semi-professional career in chess.^[5] I remember an entry on Albert Einstein in the Winkler Prins Encyclopedia we had at home, as well as two mysterious and fascinating books I bought at a library sell-out at my secondary school (the Ignatius College in Amsterdam), namely Gij en de Natuurkunde (Thou and Physics) by Paul Karlson from 1940, and De Ziel der Physica: De Wereld als Trilling (The Soul of Physics: The World as a Vibration) by H. Groot from 1941, both of which I still have. In addition, our textbook at school, Natuurkunde op Corpusculaire Grondslag (Physics on a Corpuscular Basis) by J. Schweers and P. van Vianen, which I unfortunately lost, had a beautiful colour plate with spectral lines against a black background. I was sold.

The choice for theoretical physics was also clear for me already at secondary school, though perhaps for the wrong reasons. I’m not sure I even knew that people like Einstein were theoretical physicists, but two further coincidences irrevocably drove me in that direction. First, I read an interview in a newspaper with Erik Verlinde, who was featured because off his success in a math olympiad. Surely, the journalist asked, you are going to study mathematics? No, Erik said, that would be too easy: his field was going to be theoretical physics, because that was the most difficult field of all. Second, shortly afterwards I had to undergo the medical examination for the army, which at the time still had a draft. I was almost, but not quite, exempted on the basis of height, eyesight, and mental stability (for all of which I got one but the worst scores), so something additional had to be found. My father, who was a surgeon, said he knew a cardiologist who could examine me and might find something. And indeed the cardiologist in question found a minor condition called pulmonary stenosis of the second kind, and in combination with the other grounds that turned out to be enough to be exempted. But the point is that he very kindly asked me what I was going to do after school. I answered that I considered theoretical physics. He replied: “Ah, theoretische natuurkunde, de hoogste greep!” (Wow, theoretical physics, the highest aim!).^[6] Did I need any more encouragement?

Thus I enrolled in Physics, with minors in Mathematics and Astronomy, at the University of Amsterdam in August 1981. Even during the “kandidaats-studie” (comparable to a bachelor program, which however takes three years whereas the “kandidaats” took 2.5) the ITFA was a major presence, namely through its teaching. With the exception of Special relativity and Thermodynamics, both of which were incomprehensibly given by experimentalists,^[7] as is sadly still the case in some places, the foundational courses in theoretical physics were actually taught by theoretical physicists. The ones I remember well are Quantum Mechanics and General Relativity by Gerard Bäuerle, Statistical Mechanics by Leendert Suttorp, Relativistic Kinetic Theory by Sybren de Groot, and Structure of Space-Time by Willem van Leeuwen (the latter two were probably “doctoraal” or master’s courses). Although I also read books, like Messiah’s Quantum Mechanics (North-Holland, 1966), it is these courses that remain the foundation of what I know about theoretical physics.

Suttorp had the nice habit of introducing a famous physicist at the beginning of each lecture, which some students apparently found uninteresting, so that they came late. Once this happened and the student in question, without even apologizing, asked if there were lecture notes: “Is er ook een syllabus?. Suttorp’s rejoinder was: “Er is een syllabus, maar er is ook een begintijd” ("there are lecture notes, but there is also a starting time”). The astronomy and mathematics courses were also excellent, in hindsight taught by some famous people (like Ed van den Heuvel and Jan van Paradijs in astronomy and W.T van Est, Jaap Korevaar, and Cees Lekkerkerker in mathematics). I could not have asked for more, and my choice for theoretical physics was confirmed also by the useless Natuurkundig Practicum (compulsory lab work) and incomprehensible courses taught by experimentalists (such as Structure of Matter, which, apparently directed at future experimental physicists, tried to avoid basic theory that would have made it perfectly clear what solid state physics, nuclear physics, and particle are about; I still remember the introduction of the concept of a cross-section by a full professor of experimental physics whose name I shall keep for myself: “A cross-section has something to do with the chance that particles collide, or that they don’t collide. It also has to do with the angle.” No further explanation was ever added to this, at least not during that course.

At the time the spirit created by Jan de Boer still hovered above the ITFA: theoretical physics was for the elite. This wasn’t sheer arrogance, but was motivated by the job perspective for theoretical physicists, in which, as he saw it, only the best could compete. In any case, the question who did and who didn’t belong to this elite was settled by the so-called Kleine Werkgroep (small seminar), in which some topic in theoretical physics was explored in depth. In my year, 1983, we had to work our way through a small book called Field Theory by Predrag Cvitanonic. Even with 40 years of further knowledge about its topic (namely quantum field theory, though it was far from obvious from the text that this was the topic) I hardly understand this and would not recommend it. In any case this Kleine Werkgroep was the cut, and whoever passed it was allowed into the “doctoral program” in theoretical physics (which would now be called a master’s program, as opposed to the PhD program, called “promotie” in Dutch). Just as Hilgevoord described the situation in the 1950s, such “doctoral” students got a large joint office and besides taking courses, now exclusively in theoretical physics and mathematics, sooner or later began work on their “doctoral” (=master’s) thesis. Mine was on quantum field theory at finite temperature, which was an attractive combination of statistical physics and high-energy physics.^[8] See also below for some of the other reasons behind this choice.

Two recollections from that period in the large student office stand out. First, presumably on, or a day after, October 20, 1984, Sieg Wouthuysen came into the office and asked us to be even more silent than we already were, in vacant or in pensive mood. He then solemnly said: “Paul Dirac has died”.^[9] Wouthuysen, whose name was in textbooks (Messiah’s book had a chapter on the Foldy-Wouhyusen transformation of the Dirac (!) equation), who had been a PhD student of J. Robert Oppenheimer at CalTech and then at the IAS in Princeton, where he had known Einstein in person, was living history, and we felt it at that moment. He was also related to my second recollection of the student’s office, namely our appeal, in 1984, to Dutch Parliament for the Netherlands not to take part in the “Star Wars” (Strategic Defense Initiative) project that Ronald Reagan had tried to launch in 1983, based on ideas of Edward Teller. With three other theoretical physics students (Allard Krings, Alexander Lagaaij, and Arnold Schoolderman — later Shell science superstar Dirk Smit dropped out at a late stage for reasons I can’t remember) we drafted a letter which we first circulated among top Dutch physicists, starting with Wouthuysen, who had been a leading Dutch Pugwash member for many years and needed no persuasion. Gerard ’t Hooft did, initially claiming that wars would better be fought in space than on earth, but eventually he signed, as did fresh Nobel Laureate Simon van der Meer. These top people we called (this was well before email existed, to which the ITFA was connected late 1988), and once we had their signatures we wrote to hundreds of other physicists, most of whom signed. We handed our petition in person to Relus ter Beek and achieved minor newspaper coverage, but can hardly pretend we had any influence on the discussion: the program wasn’t even carried out in the US.

My final recollection of “the old guard” at the ITFA was a Physics Colloquium by Jan Hilgevoord on his joint work with Jos Uffink, initially his doctoral and then his PhD student, on Heisenberg’s uncertainty relations.^[10] I can’t remember any seminar that fascinated me so much, and indeed their work became famous and served to establish the Netherlands as a key place for the foundations of physics. As far as I remember, Hilgevoord lost no opportunity to cloud quantum mechanics in mystery, but he did so in a different way from Bohr,^[11] namely in translating this mystery into precise language that involved both mathematics and experiments. The highlight of the talk was a comment to the effect that he had not yet revealed everything they had found out—secretly Uffink even knew what was going on behind the screen (of the double slit experiment).

During the 1980s the generation of De Boer, Wouthuysen, and De Groot retired, whilst Hilgevoord left for Utrecht. Their successors were Karel Gaemers (b. 1944, appointed in 1980), Hans Capel (1936-2023, appointed 1983), Sander Bais (b. 1945, appointed 1985), and Bernard Nienhuis (b. 1952, appointed 1989). Gaemers introduced Standard Model physics to the ITFA, which was a necessary and perhaps overdue modernization of the high-energy physics group, of whom Wouthuysen worked on current algebra (a relic from the 1960s) and Hilgevoord, as said, had moved to foundations of physics. At the time every theoretical high-energy physicist in the country if not in the world was dwarfed by Gerard ’t Hooft (b. 1946), whose PhD work in 1971 on the renormalization of non-abelian gauge theories paved the way for the Standard Model; at the time, both the (massless) Yang-Mills theory from 1954 and the (massive) Weinberg-Salam model from 1967-1968 were still extremely speculative, and quantum chromodynamics, though based on massless Yang-Mills theory, had yet to wait for the discovery of asymptotic freedom.^[12]

Bais, in turn, did what came to be called “Beyond the Standard Model physics”, which  mainly consisted of conformal field theory (CFT) and string theory. Though both (closely related) topics dated back to the sixties, CFT was given a tremendous boost by the “BPZ” paper from 1984,^[13]  the same year in which string theory exploded because of a similarly influential paper by Green and Schwarz,^[14] perhaps even more so because of its endorsement by Ed Witten, then and in the decades to come probably the only relatively young theoretical high-energy physicist whose prestige could match ’t Hooft’s.^[15]  In any case, Gaemers and Bais formed a good combination modernizing high-energy physics at the ITFA, with a broad span, even in their smoking habits, which ranged from the former’s cigarettes to the latter’s cigars.

They also personified the choice faced by aspiring young theoretical physicists like myself, and likewise, in Utrecht, future superstars Robbert Dijkgraaf and the twin brothers Erik and Herman Verlinde (who are a few years older than me): what to do for our PhD? CFT and string theory had suddenly appeared at the very frontier of research, and the timing to jump on that bandwagon looked ideal. With some friends (including Dirk Smit) I had worked my way through the two volumes of Unity of Forces in the Universe edited by Anthony Zee (World Scientitic, 1982) with growing excitement, published just before the two revolutions just mentioned, and string theory/CFT seemed the natural culmination of this quest for unification. On the other hand, with my teacher Gerard Bäuerle I had studied a book called Gauge Theory of Elementary Particle Physics by Cheng and Li, (Oxford University Press, 1982), which was an introduction to the Standard Model I also liked. Gaemers and van Weert mentioned the quark-gluon plasma as an exciting new research field within the Standard Model, with upcoming experiments at CERN in which it would be created. This area was also relevant to the cosmology of the early universe, in which I had become interested under the earlier tutelage of Willem van Leeuwen.

Apart from the pragmatic consideration that I could actually get a PhD position at the ITFA for research on the quark-gluon plasma, what really decided the matter for me was a conjunction of events, both involving Peter van Nieuwenhuizen (b. 1938), brother of the cardiologist who had saved me from the military draft and, like ’t Hooft, a former PhD student of Martinus Veltman at Utrecht. Though based in Stony Brook, he spent his summers in the Netherlands and we all knew him from his lectures as a visiting professor; I especially remember his course on Anomalies and Chern-Simons terms (at Leiden I think). “PvN”, as we called him, was one of the creators of supergravity,^[16] a precursor of superstring theory. Though his style seemed computational, he lectured as an aristocrat and his lectures and personality were attractive in every conceivable way. Nonetheless, two events tipped the balance against him and, by some bizarre and probably unjustified implication, against superstrings and the like altogether, at least as my immediate future (and, as it turned out, in my entire scientific future, since I never tuned back).

First, PvN gave a General Physics Colloquium at the UvA (like the one by Hilgevoord already mentioned), which started with Aristotle, and, via Galileo, Newton, Maxwell, and Einstein, ended not quite with himself, but certainly supergravity played an important role as the culmination of his history of physics and unification. Then and now, there was no shred of evidence for supersymmetry, but this fact did not seem to play any role.

Second, around that time (the mid-eighties) the annual Journées Relativistes were held at Amsterdam, organized by Willem van Leeuwen. This was a conference series on general relativity initiated by André Lichnerowicz (1915-1998), who still attended the meetings in person. At the conference dinner (in Monnickendam, where we were all taken by bus) he sang a moving song in French about Paris; it must have had at least 80 verses, all of which he knew by heart. PvN then apparently felt the Dutch had to respond in kind, and so he began to sing Aan de Amsterdamse Grachten,— except that he only knew the chorus. The song only has two verses which I knew and still know by heart: it was written by Pieter Goemans, my mother’s lover before she met my father. PvN could at least have asked if anyone present knew the entire song, or so I thought. The logic of my argument may have been questionable, but this was the end of my interest in anything “super”.

It is also the end of this memoir. The guard had changed, the ITFA had modernized, and moved on to become one of the leading institutes for theoretical physics in the world. It is still built on he pillars of high-energy physics (which has now mainly focused on string theory and its successors AdS/CFT and holography) and statistical physics, but has added condensed matter physics and quantum information theory as research areas. Since I left in 1989 after my PhD (which indeed was on the quark-gluon plasma and related matters) and have a very limited perspective in any case, it is for others to write this subsequent history. The institute played a huge role in my scientific development and I am forever grateful for the decade I was tied up with it, just one handshake away from Einstein and Dirac.

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^[1] Based on a talk I gave on July 3, 2025, on the occasion of the 75th anniversary of the ITFA.

^[2] Hendrik Antoon Lorentz (1853-1928) was appointed in the same year of 1877 in Leiden as the first Dutch professor in theoretical physics. Lorentz may well have been the first full professor of theoretical physics in the world, at least in so far as the name of the chair is concerned. A standard reference on the history of theoretical physics as a discipline is C. Jungnickel, R. McCormmach, Intellectual Mastery of Nature: Theoretical Physics from Ohm to Einstein, Vols. 1,2 (The University of Chicago Press, 1986), which however mainly focuses on Germany. As they describe, until about 1870 physics as carried out by physicists was almost exclusively experimental in nature, both in research and in teaching, whilst what we now call theoretical physics was done by mathematicians, or, in the U.K., by “natural philosophers” (like Kelvin and Maxwell, in the footsteps of Newton). The 1870s saw the first few extraordinary professorships in theoretical physics, installed mainly in the interest of teaching. The first full professor of theoretical physics in Germany was Boltzmann, who in 1890, well after Lorentz and van der Waals, became ordinary professor of theoretical physics in Munich (moving to Vienna in 1894). As far as I know, the first Institute for Theoretical Physics in the world was founded by Helmholtz in Berlin in 1889, who appointed Planck as an extraordinary professor, promoted to an ordinary chair in theoretical physics in 1892. Boltzmann only got his Institute for Theoretical Physics in Vienna in 1902. For the British situation see A. Warwick, Masters of Theory (The University of Chicago Press, 2003), whereas the Dutch landscape is partly covered by A.J. Kox, Hendrik Antoon Lorentz, natuurkundige (1853-1928) -  Een levend kunstwerk (Balans, 2019). See also A.J. Kox, Honderdvijfentwintig jaar theoretische natuurkunde in Amsterdam, in 50 Jaar Instituut voor Theoretische Fysica, Uitgave ter gelegenheid van het gelijknamige symposium op 10 december 1999, pp.7-23, in Dutch. For France one has to navigate between a book like I. Gratan-Guinness, Convolutions in French Mathematics 1800-1840 (Birkhäuser, 1990) and J. Gray, Henri Poincaré: A Scientific Biography (Princeton University Press, 2012). There is, of course, a difference between institutional history of this kind and actual practice. Early modern scientists (as we now call them) like Galilei, Huygens, and Newton were theoretical physicists by any standard, but they were also mathematicians, experimental physicists, astronomers, and even instrument makers, who regarded themselves and each other as natural philosophers. The idea that people exclusively did theoretical physics (without primarily being either mathematicians or experimental physicists, or something else) probably did originate in the second half of the 19th century, and is still with us!

^[3] Finally, among the professors, Jaap Hijmans (1923-2004) was around at the ITFA during my time, but I (only) now see that his chair (1980-1988) was in experimental physics. All the other appointments were in theoretical physics.

^[4] S.R. de Groot, W.A. van Leeuwen, and Ch.G. van Weert, Relativistic Kinetic Theory: Principles and Applications (North-Holland Publishing Company, 1980).

^[5] I stopped playing chess after the European Junior Championship in 1982, when I felt I could not compete with people like Valery Salov, who won the tournament, or even Simen Agdestein, who later became the coach of world champion Magnus Carlsen. At the time smoking was still allowed and I developed an allergy to this that has lasted until the present day. This was also a problem at the ITFA, where professors like Hilgevoord, and later Bais, Capel, and Gaemers, smoked in their offices, even during oral exams. I wonder how I ever managed to pass these without fainting or worse. Of course, chess is no match for theoretical physics and mathematics in any case. Of those junior chess players of my generation who became professionals, all at about the same level as me, no one achieved anything, let alone our dream to become the next Max Euwe or even just Jan Timman. Of that generation of junior chess players, Guido Imbens also wisely chose an academic career, culminating in his Nobel Memorial Prize in Economic Sciences in 2021.

^[6] The cardiologist was Rogier van Nieuwenhuizen (1942-2020). I only found out much later that he was the younger brother of the famous theoretical physicist Peter van Nieuwenhuizen (b. 1938), to whom I will return (this may explain his remark). The former later became a political enemy of my father, who proposed that medical specialists should get fixed salaries at hospitals, as opposed to being entrepreneurs, the line defended by van Nieuwenhuizen and most of the profession.

^[7] I quickly recovered from the special relativity course, partly through Jan Hilgevoord’s Electrodynamics course and partly by reading the book Spacetime Physics by Taylor and Wheeler (Freeman, 1966), which I found in the “Pre-kandidaatsbibliotheek”, a well-equipped and cosy special library for bachelor students in physics and astronomy. The thermodynamics course caused more damage; I still do not understand it. It is only now, in connection with black hole thermodynamics, that I am making a serious effort to come to grips with the topic.

^[8] The ensuing paper, signed also by my supervisor Chris van Weert (“Real-and imaginary-time field theory at finite temperature and density”, Physics Reports 145, 141-249, 1987), remains my most cited paper. The formalism developed in this thesis was initially mainly used in the theory of the quark-gluon plasma, but more recently it made a comeback in black hole thermodynamics and what is called “AdS/CFT” or holography. More than my later PhD Thesis, which I regard as a failure, it was this earlier “doctoral” thesis which helped me get my later (1989) postdoc position in DAMTP at Cambridge under John C. Taylor. To his credit, van Weert recognized my interest in mathematics, and for that reason introduced me to Marinus Winnink (1936-2023), a mathematical physicists from Groningen who in his own PhD thesis from 1967 (supervised by Nico Hugenholtz) had pioneered the mathematical side of quantum statistical mechanics and as such had co-authored what is still the most famous mathematical paper in that field: R. Haag, N.M. Hugenholtz, M. Winnink, “On the equilibrium states in quantum statistical mechanics”,  Communications in Mathematical Physics, 5, 215-236 (1967). Winnink later introduced me to Rudolf Haag, who invited me to Hamburg, where I would be a postdoc during 1993-1994. In sum, both the topic of this undergraduate thesis and my specific way of approaching it would be decisive for my later life and remains relevant 40 years later.

^[9] It reminded me of a junior chess tournament, when likewise, on November 26, 1981, the president of the Dutch Chess Federation had walked in, asked us to stop the clocks, and announced the death of Max Euwe.

^[10] Their key paper was J.B.M. Uffink, J. Hilgevoord, “Uncertainty principle and uncertainty relations”, Foundations of Physics 15, 925–944 (1985). Uffink’s PhD thesis Measures of Uncertainty and the Uncertainty Principle was eventually defended at Utrecht in 1990.

^[11] Another Dutch theoretical physicist who did internationally renowned work on foundations was H.J. (“Hip”) Groenewold (1910-1996) at Groningen. Apparently Groenewold and Hilgevoord did not get along well, perhaps because on philosophical issues the former conservatively sided with Niels Bohr whereas the latter became a follower (and friend) of Bohr’s leading critic John S. Bell.

^[12] See L.M. Brown, M. Riordan, M. Dresden, L. Hoddeson, The Rise of the Standard Model: A History of Particle Physics from 1964 to 1979 (Cambridge University Press 1997).  P. Galison, How Experiments End (University of Chicago Press, 1987) is also interesting, especially on the experimental side. The controversial book by A. Pickering, Constructing Quarks: A Sociological History of Particle Physics (University of Chicago Press, 1984) is quite informative at least as a history. See also A. Pais, Inward Bound: Of Matter and Forces in the Physical World (Oxford University Press, 1986), by an early participant in the creation of the Model. Apart from his rediscovery of the Higgs mechanism, ’t Hooft even discovered asymptotic freedom a year before Gross & Wilczek and Politzer published their computations in 1973. See G. ’t Hooft, The birth of asymptotic freedom, Nuclear Physics B254, 11-18 (1985), and G. ’t Hooft, When was Asymptotic Freedom discovered? or The Rehabilitation of Quantum Field Theory, https://arxiv.org/abs/hep-th/9808154. This story still does not sit well with the Americans. I once asked Wilczek about this, who said he hadn’t been at the Marseille 1972 meeting where ’t Hooft had shown his computation of the beta-function in an informal setting, but his friend Thomas Applequist had, and (allegedly) couldn’t remember anything. It seems fair to say that asymptotic freedom was just one part of the puzzle that was solved by QCD; ’t Hooft himself wrote that ‘I must add that at that time I was totally ignorant of strong interaction phenomenology.’ (1985 paper just cited, p. 14).

^[13] A.A. Belavin, A.M, Polyakov, A.B. Zamolodchikov, Infinite conformal symmetry in two-dimensional quantum field theory, Nuclear Physics B241, 333-380 (1984).

^[14]M.B. Green, J.H. Schwarz, Anomaly cancellation in supersymmetric D = 10 gauge theory and superstring theory, Physics Letters B149, 117-122 (1984).

^[15] Both Feynman and Schwinger were still alive at the time, and certainly also younger people like Steven Weinberg still counted. But ’t Hooft and Witten dominated the next generation. 

^[16] D.Z. Freedman, P. van Nieuwenhuizen, S. Ferrara, Progress toward a theory of supergravity, Physical Review D13, 3214-3218 (1976).