Ann. Phys. (Leipzig) 10 (2001) 1–2, 151 – 162
The emergence of Quantum Schools:
Munich, Göttingen and Copenhagen as new centers
of atomic theory
M. Eckert
Institut für Geschichte der Naturwissenschaften, Sommerfeld-Edition, Universität München,
D-80306 München
Germany
[email protected]
Received 8 Sep. 2000, accepted 6 Oct. 2000 by C. Thomsen
Abstract. The institutes of Arnold Sommerfeld in Munich, Niels Bohr in Copenhagen, and
Max Born in Göttingen became the leading centers for the study of quantum theory in the first
decades of the twentieth century. Although founded for a broader range of theoretical physics,
the quantum became the major topic of research in Munich after the Bohr-Sommerfeld-model
of the atom (1913–16). The heyday came in the 1920s, when Bohr’s and Born’s institutes
started operation and became further attractive centers for ambitious theorists all over the
world. The discovery of quantum mechanics (1925) should be regarded not only as the
achievement of a few young geniuses (in particular Werner Heisenberg and Wolfgang Pauli)
but also as the result of a collaborative effort emerging in the new social and intellectual
environment of their teachers’ schools in Munich, Göttingen and Copenhagen.
Keywords: Arnold Sommerfeld, Niels Bohr, Max Born
PACS: 61.43.–j, 71.30.+h, 73.40.Hm
1
Introduction
Quantum physics is no virgin field in the history of physics. It was already more than
thirty years ago ripe for a review on “quantum historiography” by John Heilbron [1],
who resumed the state of the art as a member of the then recently closed project
Sources for History of Quantum Physics–an effort that resulted in about 200 interviews
with almost 100 quantum pioneers and 100,000 frames of material microfilmed from
original sources preserved in more than 250 archives, among them for example Bohr’s
Scientific Correspondence [2]. This review, together with the amount of material
collected, provides a sense of the richness and complexity of quantum history. If one
takes into account the literature produced since then, such as the various volumes
on The Historical Development of Quantum Theory [3], the multi-volume-editions of
scientific writings like that of Wolfgang Pauli [4], or the many biographies of quantum
pioneers, the impression becomes overwhelming that there is nothing left than to fill
minor details here and there in order to round off an already well established picture.
Nevertheless, there is no consensus about the most prominent features of the his-
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tory of quantum physics. With each new biography or new record the historical roots
seem to become submerged in an ever growing jungle of details. Occasional attempts
to obtain a more coherent picture, such as Paul Forman’s theses about the Zeitgeist of
Weimar physics, only gave rise to new controversy [5]. Between the Scylla of overboarding and diverging details on the one hand and the Charybdis of undue reductionism
on the other, quantum history is in need of new perspectives. In this paper I focus
on the most important schools of quantum and atomic theory in the beginning of the
twentieth century. Such an approach keeps enough biographical detail of individual
contributors and at the same time sheds light on more general features. Research
schools have been recognized as important units for historical analysis in many sciences and their study can open new directions in the historiography of science [6].
Although it was repeatedly noticed that research schools also played a major role in
the history of quantum physics (e.g. [7–9]), their role for the emergence, consolidation,
and ramification of quantum theory has not yet become a theme of closer historical
scrutiny.a
2
Sommerfeld’s Munich “nursery”
A sense of the importance of research schools for the growth of quantum theory is obtained when we consider the list of quantum pioneers who experienced their initiation
into the world of quanta and atoms in Munich, Copenhagen, or Göttingen (see Table
1). The earliest of these centers was founded by Arnold Sommerfeld in his institute for
theoretical physics at the University of Munich. The diversity of the physicists’ mentalities (comprising such different personalities as that of Wolfgang Pauli and Peter
Debye even within one and the same school) illustrate the above mentioned complexity
in the history of quantum physics. Not taking their common scientific heritage into
account would not allow a coherent picture to emerge from a compilation of these
names.
When Sommerfeld became professor of theoretical physics at the University of Munich in 1906, quantum theory was barely existing as a field of physics research [10].
Neither by his previous work nor by his contemporary research interests was Sommerfeld predestined to become a founding father of modern quantum and atomic theory.
After beginning as a mathematician under the legendary Felix Klein in Göttingen and
holding chairs for mathematics at the Bergakademie Clausthal (1897–1900) and for
mechanics at the Technische Hochschule Aachen (1900–1906) Sommerfeld was eager
to demonstrate the power of mathematics in theoretical physics–a specialty of rather
meager renown in the beginning of the twentieth century. This was to change in the
years to come, and this was the ambition with which Sommerfeld came to Munich.
Together with Peter Debye, who had become his assistant in Aachen and accompanied him to Munich to turn from an engineer into a physicist, Sommerfeld intended
to turn his Munich chair and the associated institute into a “nursery of theoretical
physics” [11].
a The present work emerged as part of the editing of Sommerfeld’s scientific correspondence. For
more information about this project see: http://www.lrz-muenchen.de/~Sommerfeld/
M. Eckert, Emergence of Quantum Schools
153
The early years of Sommerfeld’s school before the first world war mirrored the
situation of theoretical physics as a discipline in its infancy. There were few models
for course lectures, lectures for advanced topics, seminars and colloquia. Doctoral
dissertations in theoretical physics were often accompanied by experimental work.
Sommerfeld himself tried to keep close contact with experiments and employed an
experimental assistant as well as a mechanic in a laboratory in the basement of his
institute–the site of the discovery of x-ray diffraction in crystals in 1912. Despite the
haphazard circumstances which led to this epochal result, Sommerfeld still in 1926
called it “the most important scientific event in the history of the institute,” at a
time when he could look back on more than a decade of outstanding advances in
atomic theory. To be in close touch with experimental results was as characteristic of
Sommerfeld as his broad mathematical orientation; both traits were remainders of the
origins of his own beginnings in the field [12].
The new “nursery” soon became known among theoretically minded physicists:
“I assure you that, if I were in Munich and time would permit it, I would attend
your lectures in order to accomplish my mathematical-physics knowledge,” Einstein
wrote to Sommerfeld in 1908 from Bern in Switzerland, where he worked in the patent
office [13]. Paul Ehrenfest wrote in 1911 to Sommerfeld how much he wished to go to
Munich “in order to learn – among many other things – particularly this under your
personal supervision: how one performs a research work which requires a true effort
of calculation” [14]. If there was a common trait of research in the early Sommerfeld
school, it was the broadness of research themes, ranging from hydrodynamics to metal
electrons, from x-rays to wireless telegraphy.
Quantum theory emerged around 1910 as a new area of interest: Sommerfeld, in
an effort to extend his earlier Bremsstrahlen-theory of x-rays, made use of Planck’s
constant h in a theory about γ-rays. He generalized his ideas into an h-hypothesis,
according to which Planck’s constant was identified as the fundamental action (energy times time) which regulated elementary emission and absorption processes. The
appearance of Planck’s constant in speculations about atomic processes was not unusual, such as in a model by Arthur Erich Haas, where h was “derived” by associating
it with atomic quantities. Sommerfeld, however, adopted the view that one should
“not explain h from molecular dimensions but regard the existence of molecules as a
function and consequence of the elementary quantum of action” [15]. He disseminated
this opinion at many occasions, such as during the first Solvay conference 1911 in
Brussels, but he could not substantiate it by new theories and turned again to other
areas where he could achieve concrete results.
When Niels Bohr published his atomic model in 1913, Sommerfeld reacted with
cautious praise: “The problem of expressing the Rydberg-Ritz constant by Planck’s h
has been in my mind since long. I talked about it with Debye a few years ago. Although
I am still somewhat sceptical about atomic models in general, the calculation of this
constant is without question a great accomplishment” [16]. But it took another two
years before Sommerfeld became actively involved in the further development of Bohr’s
atomic model, a time during which he did not motivate his pupils to work on quantum
theory. Apparently he first familiarized himself with Bohr’s theory in a lecture course
during the winter semester 1914/15. In December 1915 he worked “with full steam and
fabulous results” on the extension of Bohr’s model. “By quantizing the excentricity of
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Ann. Phys. (Leipzig) 10 (2001) 1–2
the ellipses (in addition to the orbital motion), I show that there are m possible orbits
for each Balmer term 1/m2 ,” he wrote to the astronomer Karl Schwarzschild [17].
By introducing a second quantum condition and calculating the elliptical motion of
an electron around the nucleus according to the theory of relativity, Sommerfeld was
able to account for the fine-structure in the atomic spectra. Friedrich Paschen, an
experimental spectroscopist, confirmed Sommerfeld’s theory with precise data.
After this success Bohr’s atomic theory became a matter of broader concern, first
for Sommerfeld himself, then for his pupils, and finally for the still small community of
theorists in general. The first Sommerfeld pupil who dealt with the Bohr-Sommerfeldmodel was Paul Epstein. He worked out a theory for the Stark effect. Independently
and simultaneously Karl Schwarzschild achieved the same results in a more elegant
manner using angle-action-variables known to him as an astronomer but rather unfamiliar among physicists then. Sommerfeld later called this method the “royal road”
for atomic problems. As another application of his extended Bohr model Sommerfeld
published in summer 1916 a theory of the (normal) Zeeman effect. His student Debye,
now a professor in Göttingen, competed with him in this effort and achieved practically
the same results at the same time. Within half a year after Sommerfeld’s first paper
on the extension of Bohr’s atomic model this theory had turned into a flourishing new
research field for theoretical physicists [18–20].
The fecundity of this new field became apparent after the end of the first world war.
Sommerfeld had begun to write a book titled Atombau und Spektrallinien on the new
atomic physics during the last year of the war. Its appearance in 1919 coincided with
an upsurge of interest in scientific research by a new generation of students who filled
the university lecture halls after four years of wartime agony. Sommerfeld’s seminar
became a market place of young talents eager to demonstrate their intellectual skill,
and their teacher seemed never at a loss for new research themes. “What I admire
about you in particular,” congratulated Einstein in 1922, “is that you have generated
from nothing such an enormous number of young talents. This is something quite
unique. You must have a gift to ennoble and activate the minds of your audience” [21].
Einstein wrote this in response to Sommerfeld’s mentioning of Werner Heisenberg,
then a third-semester student, who had impressed him with a new model concerning
the riddle of the anomalous Zeeman effect. A few years later, at the occasion of
Sommerfeld’s sixtieth birthday, Heisenberg recalled his study period and wished that
Sommerfeld would “for a long time continue to run a nursery for physics babies like
at the time for Pauli and myself” [22].
3
The Niels Bohr Institute in Copenhagen
When Bohr became the “father of the atom” [23] with his epochal “trilogy” On the
Constitution of Atoms and Molecules in 1913, he was still without a secure position,
working more often abroad with Rutherford in England than in his home country
Denmark. In 1916 he was appointed professor of theoretical physics at the university
of Copenhagen–a post which he had pleaded to establish two years ago at the Ministry
of Education. But this was only little more than a title. He had to share a small room
with his assistant. In contrast to Sommerfeld’s chair in Munich, Bohr could not dispose
M. Eckert, Emergence of Quantum Schools
155
of a laboratory nor other means to perform efficient research in physics. From the very
beginning it was obvious that more favorable working conditions and possibly a new
institute would have to be created if the new Danish star of atomic theory would not
be lured away to a better equipped university abroad.
As in Munich a decade earlier, the beginnings of Bohr’s school were characterized by
haphazard circumstances. Bohr had to lecture on a variety of topics for an audience
of six to eight advanced students. With the help of his devoted assistant Hendrik
Anton Kramers, who had come from the university of Leiden in Holland to the neutral
Denmark in the hope to continue his mathematics and physics studies, research in the
theory of atoms continued, but the pace of progress was slow. Despite the unfavourable
working conditions the collaboration became most fruitful. Kramers turned “from
student to apostle,” as his biographer put it, and stayed for ten years [24].
In April 1917 Bohr sent a proposal to the Faculty of Science and Mathematics of
the University of Copenhagen in which he pleaded for the establishment of an institute
for theoretical physics appropriate for modern research and teaching. “In order that
education in theoretical physics can be conducted in a manner corresponding to the
subject’s importance in the study of science, it is necessary that under guidance the
students have the opportunity to carry out calculations and, through the demonstration and independent study of practical models, to become familiar with and form for
themselves a clear picture of the often abstract and mathematically complicated theories of fundamental physical phenomena. An institute for theoretical physics therefore
must first of all contain, besides an auditorium and library, space for a model collection and rooms for the students to use for theoretical exercises and calculations” [25].
One and a half years later, the official permission was issued to start with work for
the institute. Another two and a half years later, in March 1921, the inauguration
ceremonies took place.
From the very beginning Bohr was eager to emphasize the international character
of his future institute. “The Institute of Mr. Bohr should not only serve the upcoming
generation of Denmark, it will also be an international place of work for foreign talents
whose own countries are no longer in a position to make available the golden freedom of
scientific work,” Sommerfeld echoed Bohr’s intentions in a recommendation addressed
to the Carlsberg Foundation in support for a grant in October 1919 [26]. A few weeks
earlier Sommerfeld had visited Bohr in Copenhagen during a lecture tour through
Scandinavia – a visit followed with great interest so soon after the war. And Bohr did
not wait for the completion of his institute with further invitations of international
guests: Adalbert Rubinowicz, a physicist from Poland who served as Sommerfeld’s
assistent during the last year of the war, spent a sojourn of several months in Copenhagen in 1920; other early visitors were James Franck, George de Hevesy and Alfred
Landé. When the institute finally opened, it became a first address for international
researchers in atomic physics. Within the first ten years there were 63 visiting physicists from 17 countries: 14 from the USA, 10 from Germany, 7 from Japan, 6 from
the Netherlands, 6 from the United Kingdom, 4 from Norway, 3 from the USSR, and
one from Austria, Belgium, Canada, China, Hungary, India, Poland, Romania and
Switzerland [27]. (An abbreviated list of these visits is contained in Table 1) .
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Ann. Phys. (Leipzig) 10 (2001) 1–2
Table 1 Attendance in the Nurseries of Quantum Theory (after [2])
Who was when in
Munich
Bechert, K.
Bethe, H. A.
Bloch, F.
Brillouin, L.
Colby, W. F.
Compton, K. T.
Debye, P.
Delbrück, M.
Dennison, D. M.
Dirac, P. A. M.
Eckart, C.
Elsasser, W.
Epstein. P. S.
Ewald. P. P.
Fermi, E.
Foster, J. S.
Fowler, R.
Franck, J.
Fues, E.
Gamow, G.
Goeppert-Mayer, M.
Goudsmit, S. A.
Hartree, D. R.
Heisenberg, W.
Heitler, W.
Herzfeld, K. F.
Hevesy, G. de
Hönl, H.
Houston, W. V.
Hoyt, F. C.
Hulthén, E.
Hund, F.
Hylleraas, E. A.
Joos, G.
Jordan, P.
Kemble, E. C.
Kimura, K.
Klein, O.
1920–25, 1926–33
1926–28, 1929–30
Copenhagen
Göttingen
1931–32
1912–13
1912–13
1906–11
1931–32
1924–26, 1927
1926–27
1927–28
1923–24
1911–17
1907–12, 1913–21
1918–20
1926
1913–20
1926–30
1924–27
1912–13
1923–24
1926–27
1925
1921
1927
1928–31
1921–33
1926–30
1920–23
1924–26
1920–26
1926–27
1928
1924–25, 1926–27
1926–27
1923–24, 1925–26
1927–33
1920–26
1923–26
1927–28
1922–24
1927–29
1926–27
1920–26
1924–28
1922–24
1926
1927
1925–27
1926–31
1922–27
1927
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M. Eckert, Emergence of Quantum Schools
Table 1 cont.
Munich
Kossel, W.
Kramers, H. A.
Kratzer, A.
Kronig, R.
Kuhn, W.
Landau, L.
Landé, A.
Laporte, O.
Laue, M.
Lenz, W.
London, F.
Möller, C.
Mott, N.
Niessen, K. F.
Nishina, Y.
Nordheim, L. W.
Oldenberg, O.
Oppenheimer, J. R.
Pauli, W.
Pauling, L.
Peierls, R.
Rabi, I. I.
Rosenfeld, L.
Rosseland, S.
Rubinowicz, A.
Slater, J. C.
Thomas, L. H.
Uhlenbeck, G. E.
Urey, H. C.
Weisskopf, V. L.
Wentzel, G.
Wigner, E. P.
Copenhagen
Göttingen
1913–21
1916–26
1916–20, 1921–22
1912–14
1921–24
1909–12
1908–20
1917–21
1920–21
1925, 1927
1924–26
1930
1920
1913–14
1921–27
1923–34
1928
1925–26
1922
1918–21
1926–27
1926–28
1927–28
1916–18
1923–28
1928, 1929
1922–23
1927
1927
1935–40
1920–24
1920, 1922
1923–24
1925–26
1927
1923–24
1932–33
1922–27, 1928–32
1923–30
1926–27
1921–22
1927–29
1927
1928–31
1920–26
1927–28
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Ann. Phys. (Leipzig) 10 (2001) 1–2
The constant influx of visiting physicists from abroad did not hinder the routine
tasks of the Institute for the local students. Bohr’s assistants – Kramers until 1926,
Heisenberg until 1927, thereafter Oskar Klein – also served as lecturers and had to
present the regular course lectures in theoretical physics master’s degree students in
physics. Advanced students were invited to review new research papers and to attend
the presentations of visiting physicists in the regular seminar of the institute. It was
Bohr’s deliberate intention to thereby encourage a close relationship between teaching
and research, without formal barriers between students and accomplished physicists.
Despite such similarities between Sommerfeld’s and Bohr’s schools, there were distinct differences. While Sommerfeld approached a new field in a rather pragmatic
manner (“how this happens remains completely mysterious, but the consequences of
this postulate must be analysed,” he argued for example in his electron theory of
metals in 1927, where he studied the consequences of the postulate of a free electron
gas obeying Fermi-Dirac-statistics [28]), Bohr was guided by more principal lines of
thought. Sommerfeld’s pragmatism allowed him to challenge his pupils with a broad
spectrum of research topics from all parts of physics, but it was left to his pupils’
interests whether they would enter more deeply into the philosophical or metaphysical underpinnings of a research problem. Bohr focused more narrowly on quantum
problems and how they deviated from classical physics. His guiding line of thought
was the correspondence principle. He hoped to solve the difficulties of quantum theory “by trying to trace the analogy between the quantum theory and the ordinary
theory of radiation as closely as possible,” he once argued [29]. And this was the
spirit he implanted into the minds of his pupils: “My work closely follows the tracks
of the correspondence principle,” Heisenberg wrote to Sommerfeld from a sojourn in
Copenhagen with Bohr [30].
There are many recollections about Bohr’s probing into the nature of a problem
during never ending discussions with his students and collaborators. “Bohr found a
new characteristic way of working,” Victor Weisskopf recalled. “He did not work as an
individual alone, he worked in collaboration with others. It was his greatest strength to
assemble around him the most active, the most gifted, the most perceiving physicists
of the world” [31]. But Bohr’s insistence on preconceived principles sometimes also
caused irritations. When John Slater came up with a new idea about electromagnetic
waves emitted by atoms, Bohr and Kramers reshaped it into what became known as
the Bohr-Kramers-Slater-theory, denying the existence of photons because there was
no place for them in Bohr’s correspondence principle. “They grudgingly allowed me to
send a note to Nature indicating that my original idea had included the real existence
of the photons, but that I had given that up at their instigation,” Slater recalled many
years later. “This conflict, in which I acquiesced to their point of view but by no
means was convinced by any arguments they tried to bring up, led to a great coolness
between me an Bohr, which was never completely removed” [32].
4
Max Born’s Göttingen School
Both Sommerfeld and Bohr started practically from zero when they created their
schools in Munich and Copenhagen. Although it is tempting to assume a direct
M. Eckert, Emergence of Quantum Schools
159
tradition from Boltzmann’s atomism–Sommerfeld’s chair was created in 1890 to win
Ludwig Boltzmann for Munich–to Sommerfeld’s atomic theory, there was no such continuity. Boltzmann left Munich after only four years, and the chair was abandoned
until Röntgen recreated it twelve years later [33]. In Copenhagen there was not even
a precursor chair upon which Bohr could have built his own teaching and research.
This was different in Göttingen. Even before Max Born’s appointment as professor
and director of the Institute of Theoretical Physics at the University of Göttingen in
1920 there was a tradition in modern theoretical physics, established by ambitious
mathematical and physical research programs under the guidance of such celebrities
as David Hilbert, Felix Klein, and Peter Debye [34].
Born built upon this tradition and added his own scientific entrepreneurship and
research strategies to it. When he negociated in the Berlin Ministry of Education
about the terms to accept the position as successor of Debye in Göttingen, he found
out that there was another opening and made his acceptance dependent on the simultaneous appointment of James Franck. Due to this maneuver the University of
Göttingen acquired one of the best teams of physicists in the world: the experimental
physicist Robert W. Pohl, who directed the First Institute of Physics and founded an
important school of solid state physics, James Franck, director of the Second Institute
of Physics, focusing on experimental atomic physics in close cooperation with Born’s
Institute of Theoretical Physics. Each institute had two positions for assistants. The
schools of this remarkable trio became called the “Bornierten”, the “Franckierten”, and
the “Pohlierten”. Among the colleagues from neighboring institutes who contributed
to the blossoming of Göttingen physics in the 1920s were Hilbert, who together with
a “physics” assistant took a keen interest in theoretical physics, Carl Runge, an expert in applied mathematics, Ludwig Prandtl, who pioneered fluid dynamics, and the
astronomer Hans Kienle.
Born’s own scientific tradition was rooted in mathematics [35]. His academic career began with a collaboration with the great Göttingen mathematician Hermann
Minkowski on the theory of relativity; after Minkowskis death in 1909, he worked on
solid state theory. Before he was called as Debye’s successor to Göttingen he had
held chairs for theoretical physics in Berlin and Frankfurt. In 1922 he completed a
monumental review on the “Atomic Theory of the Solid State” for the Encyklopädie
der mathematischen Wissenschaften, edited by Sommerfeld, a pioneering effort for the
emerging discipline of solid state physics. But Born’s main interest after his move
to Göttingen was atomic mechanics, a notion coined by him in analogy to celestial
mechanics. “As this delineates the part of theoretical astronomy concerned with the
orbits of celestial bodies according to the laws of mechanics, the notion of atomic
mechanics should express that here the facts of atomic physics will be dealt with
under the particular point of view of applying mechanical principles,” he introduced
his Vorlesungen über Atommechanik, published in 1925 on the eve of Heisenberg’s
breakthrough to quantum mechanics.
From the very beginning Born was eager to establish a strong school for atomic
and quantum theory in Göttingen. “I let my people ’quanteln’ to enter into competition with you,” he teased Sommerfeld in 1922 [36]. Like Sommerfeld he established
a six-semester course through all parts of theoretical physics, accompanied by special
lectures and seminars, such as a regular seminar with Hilbert on the “structure of mat-
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Ann. Phys. (Leipzig) 10 (2001) 1–2
ter” or a “private” seminar held in his own appartment during the winter semester
1922/23 about the mathematical methods in celestial mechanics. Sommerfeld welcomed the new competitor and entrusted him with his own students when he left
Munich for an invitation to the USA as a guest professor in Madison (Wisconsin)
during the winter semester 1922/23. “I have in addition to your four descendents 9
doctoral students,” Born reported in a letter to Sommerfeld in January 1923. One
of the four Munich “descendents” was Werner Heisenberg: “I am very fond of him,”
Born wrote and added that he would like to keep him as his assistant. “When I asked
him what he intended to do afterwards (i.e., after the doctoral work with Sommerfeld)
he responded: ’That is not up to me to decide. This Sommerfeld will decide!’ So you
are his self-chosen guardian, and I have to ask you for permission to lure him away to
Göttingen” [37].
Heisenberg became Born’s assistant a year later. Before him, another Munich “descendent”, Wolfgang Pauli, was Born’s assistant. Moving from one center to the next
became the rule and not the exception, as may be seen from Table 1. Other members
of Born’s school were Erich Hückel, Friedrich Hund, Walther Heitler, Pascual Jordan,
Fritz London, Eugene Wigner, Maria Göppert-Mayer, Max Delbrück, and Viktor Weisskopf, to name only a few. By comparison to Munich and Copenhagen, the Göttingen
school of quantum theory had its own distinct orientation. Hund expressed the role of
these three schools for the development of quantum mechanics in this formula: “Quantum mechanics was a synthesis of the styles of thought of Copenhagen, Munich and
Göttingen. Heisenberg’s boldness, entrained by Sommerfeld’s pragmatism, augmented
by a grown sense for the fundamental things due to Bohr’s philosophical consciousness,
came together with Born’s striving for mathematical consistency” [38].
5
Conclusion
Physicists visiting or studying in any number of these centers “got to know practically
all the scientists active during the classical decade of 1923–1932,” as John Slater
recalled; for them it was obvious that the quantum revolution was a collaborative
effort: “The group of scientists working on the quantum theory in those days was
small – maybe 50 to 100 wellknown names” [39]. The schools of Munich, Copenhagen,
and Göttingen were the most important ones, but for more completeness we would
have to add also the emergence of schools at Leipzig (Heisenberg), Zurich (Pauli), MIT
(Slater), or Bristol (Mott), where the spread and application of quantum mechanics to
new areas such as solid state theory flourished in the late 1920s and early 1930s [40].
Of course, there were also individual contributors to the quantum revolution who
cannot be attributed to one of these schools (like Erwin Schrödinger or Paul A. M.
Dirac), but they too became involved with these schools when they were invited to
present their achievements (Schrödinger’s presentation of wave mechanics in Munich
and Copenhagen caused major reverberations there).
The history of these schools, therefore, mirrors the quantum revolution without
becoming frayed into dozens of disjointed stories. First of all it makes apparent to what
extent this history was the result of a cooperative enterprize. It does not denigrate
outstanding singular contributions of geniuses like Heisenberg or Pauli, if they are
M. Eckert, Emergence of Quantum Schools
161
embedded into the broader social and intellectual environments of these schools.
But the emergence of the Munich, Copenhagen, and Göttingen schools sheds light
not only on on the quantum revolution. Atomic and quantum theory became pacemakers of theoretical physics. Sommerfeld’s school was probably the first school of
theoretical physics in general. Atoms and quanta were not the only themes, but when
they emerged as new research topics, they became targets of opportunity for a new
generation of theorists. The heyday of atomic theory in the 1920s was one for modern
physics as a whole. Henceforth, a modern physicist was a physicist with expert knowledge in quantum mechanics. From this perspective it seems reasonable to conclude
that the history of Sommerfeld’s, Bohr’s and Born’s schools is at the core of the social
and intellectual history of the entire discipline of theoretical physics.
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[3] J. Mehra and H. Rechenberg, The Historical Development of Quantum Theory, vol. 1,
Springer, New York, 1982
[4] K. von Meyenn, ed., Wolfgang Pauli, Wissenschaftlicher Briefwechsel, vol. 1, Springer,
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