In the 1950s I studied physics at Birkbeck College in London, first as an undergraduate and then as a postgraduate research student under the supervision of the Reader in Theoretical Physics, Dr Reinhold Fürth, an émigré from Continental Europe who had taken his doctor’s degree at the University of Prague. I mention this because from the beginning of the Second World War, Fürth had been a research assistant in Max Born’s Natural Philosophy department at the University of Edinburgh. He became one of Born’s principal collaborators in the department’s research school that flourished after the war (another principal collaborator at the time was Klaus Fuchs, who was arrested in 1950 for passing nuclear secrets to the Soviet Republic). Fürth later described Born’s zest in directing his research students, even when approaching retirement age:

When Born arrived in the morning he first used to make the round of his research students, asking them whether they had any progress to report, and giving them advice, sometimes presenting them with sheets of elaborate calculations concerning their problems which he himself had done the day before . . . Being such an incredibly fast worker himself he could on occasion become quite impatient when he found that a student had not managed to complete the calculations which had been suggested to him only the day before. The rest of the morning was spent by Born in delivering his lectures to undergraduate honours students, attending to departmental business, and doing research work of his own. Most of the latter, however, he used to carry out at home in the afternoons and evenings[1]

At Birkbeck, the aspects of physics on which Born worked during the 1920s, lattice dynamics and the principles of quantum mechanics in particular, were part of the curriculum, and still, despite the passage of 30 years, remarkably fresh to our young minds. We were learning the ‘new’ physics. At undergraduate level, Born’s Atomic Physics, a lucid, masterly, and wide-ranging text book, was required reading, as it was in physics departments throughout the world. First published in 1933, it ran to eight editions, keeping pace with developments until 1969, the year before Born died. Surprisingly, there has been no previous biography of this great theoretical physicist, a Nobel prize-winner and a life-long friend of Albert Einstein. Born collaborated with, or taught, acclaimed scientists such as Theodore von Kármán, Wolfgang Pauli and Werner Heisenberg, and, although a pacifist, counted among his students many luminaries who went on to develop the atomic bomb: Robert Oppenheimer, Edward Teller, Eugen Wigner, and John von Neumann among them. So Nancy Greenspan’s well-researched record of Born the scientist and Born the private man deserves a very warm welcome.

There is, however, a problem for the general reader. Quantum mechanics is, to say the least, difficult to understand. As David Griffiths explains in his excellent Introduction to Quantum Mechanics, aimed at today’s physics undergraduates, “Unlike Newton’s mechanics, or Maxwell’s electrodynamics, or Einstein’s relativity, quantum theory was not created – or even definitely packaged – by one individual, and it retains to this day some of the scars of its exhilarating but traumatic youth. There is no general consensus as to what its fundamental principles are, or what it really means.” A biography cannot avoid, or entirely solve, these difficulties. Those readers unable to follow the mathematical and physical details – and I include myself among them – will still gain insight into ‘exhilarating but traumatic’ times, and the part played by Born and others in bringing about this radical departure from classical science. Simplified, non-mathematical descriptions of the process are given in the presentation speeches at the Nobel Prize ceremonies for Heisenburg (1932) and Born (1954), to which I refer below. Greenspan, mercifully perhaps, includes just one mathematical equation, but it is the equation which Born described as his greatest scientific achievement: the fundamental commutation law of quantum mechanics, first jotted down in July 1925. It is carved on his gravestone: “pq-qp=h/2πi”.

Greenspan excels in her descriptions of Born as family man, as professor in the “tradition of the wandering medieval German scholars”, and as a person caught up in virulent anti-Semitism in Germany even before Hitler came to power. At the University of Göttingen in the mid-1920s: “Hundreds of students, faculty and townspeople marched through the meandering streets and alleys, flaming torches held high, the night sky lit up in the grand Göttingen tradition. James Franck [Professor of Experimental Physics at Göttingen and Born’s close friend] and his former research partner, Gustav Hertz, had won the Nobel Prize for their research on electron collisions. The throng of well-wishers eventually collected in the market square in front of the medieval Rathaus for speeches, food, and drink. Born’s excitement about Franck’s recognition merged with his pride of having brought him to Göttingen.”  And yet, most ominously,  “In 1925, a twenty-two year-old chemistry student named Achim Gercke began to compile a list of all German professors [at Göttingen] of Jewish origin. He called it “The Archives of Racial Statistics for Employment Classes”, the purpose of which was to provide “a weapon in hand that should enable the German Reich to exclude the last Hebrew and all mixed race from the German population in the future and expel them from the country.” Franck later was to emigrate after protesting Hitler’s racial policies. Gercke was rewarded for his odious  zeal with  the post of director of Racial Service in the Third Reich.

Born was born in 1882 at Breslau, then in Germany (now Wroclaw, Poland). His father was a professor of anatomy; his mother came from a prosperous family of textile manufacturers. Both sides of the family were well steeped in German culture. ‘They believed they differed from their neighbours only in respect of religion, for which they had no time,’ Max recalled. Poetry, music and science pervaded the household and Max became an accomplished pianist. He was, however, asthmatic and frail. His mother died when he was four, leaving an emotional void, and he retreated into shyness. His father died suddenly in 1900 when Max was seventeen years old and coming to the end of his schooling at the local Gymnasium. He had been deeply influenced by his father and from him inherited a profound dislike of organised religion and the military. Thanks to the support of a close family friend, who passed on to him his socialist views, he completed his exams at the Gymnasium and entered the University of Breslau to study philosophy, science and mathematics.

The German university system was such that students could change universities almost ‘to match the seasons’. Born spent a summer semester in Heidelberg, and another in Zurich, before moving from Breslau to Göttingen, a world-famous centre for mathematics. Here he became an unpaid assistant to David Hilbert, one of three ‘high priests’ of German mathematics. In 1906, he was awarded a PhD in mathematics and returned to Breslau to do his compulsory military service. This fortunately was cut short by an asthma attack and his friend James Franck then persuaded him to go to the Cavendish Laboratory at Cambridge University ‘to see what real physicists do.’ This switch was not a success inasmuch as the experimental tasks he was given were beyond his competence, but the experience did point him in the direction of his major contributions: the application of mathematical techniques to solve new problems in physics.

Born returned to Breslau and again tried his hand at experimental work without much success. He went to Göttingen to work on an aspect of relativity for his Habilitation – a certificate which a German PhD had to take before being allowed to teach at a university. In October, 1909, Born received permission to teach and became a lecturer in the Philosophical Faculty at Göttingen. Lecturers received no salary but relied on payments from those attending lectures. Born at first was not a captivating lecturer and so lived frugally on a small inheritance. Yet, he soon teamed up with Theodore von Kármán to develop a theory of the specific heat of solids. This was the beginning of a program of research on the properties of crystals based on their lattice structure which Born was to pursue for many years, while von Kármán turned to thermodynamics.

In 1913, Born married Hedi Ehrenberg. Their relationship was turbulent – Hedi frequently ‘run-down’ and retreating to sanatoriums, Born always intensely bound up in his work. Hedi had a long-lasting affair with another professor at Göttingem, but in later life, she and Born grew closer together. Born’s innovative work on relativity, specific heat and crystal lattices brought him to the attention of other universities and in 1914 he took up a professorship in theoretical physics at the University of Berlin. Here he met Einstein who frequently visited the Born household to talk science and play violin sonatas, with Max on piano. It was the beginning of a long friendship. With the advent of the First World War Born was assigned to the artillery to work on range-finding. Afterwards he moved to the University of Frankfurt. In 1921, he became Director of the Institute of Theoretical Physics at Göttingen and with the help of two highly gifted assistants, Wolfgang Pauli and Werner Heisenberg, succeeded in turning it into a leading centre for research in quantum theory.

The first breakthrough came from Heisenberg, but this was rendered into a powerful mathematical formulation by Born and his student, Pasqual Jordan. A third paper by Born, Heisenberg and Jordan placed quantum mechanics on a very firm footing. Still, the laurels went wholly to Heisenberg: a1933 Nobel Prize in physics for his creation of quantum mechanics. Born was deeply hurt that his contribution went unrecognized, but never complained publicly. However a bittersweet refrain running through Greenspan’s biography is that Born lost no opportunity to make his aggrieved views known to friends. More than thirty years elapsed before Born received the Nobel Prize for the ‘fundamental research in quantum mechanics, especially for his statistical interpretation of the wave function’ conducted in Göttingen. Greenspan relates that Born was especially gratified that it cited an area that he had developed alone. To comprehend the achievement a lay reader might benefit from reading the non-mathematical descriptions of these achievements in the Nobel Prize Presentation Speeches for Heisenberg and Born, which are to be found on www.nobelprize.org/physics/laureates/1932 for Heisenberg and /1954 for Born. Briefly,

Born, in collaboration with his pupil Jordan and later Heisenberg also, was able to expand the latter’s original results into a comprehensive theory for atomic phenomena. This theory was called quantum mechanics….The following year Born got a new result of fundamental significance. Schrödinger had just then found a new formulation for quantum mechanics. Schrödinger’s work expanded the earlier ideas of De Broglie which imply that atomic phenomena are connected with a wave undulation… Born found that the waves determine the probability of the measuring results. For this reason, according to Born, quantum mechanics gives only a statistical description. This can be illustrated by a simple example. When you shoot at a target it is possible in principle to aim the shot from the start so that it is certain to hit the target in the middle. Quantum mechanics teaches us to the contrary – that in principle we cannot predict where a single shot will hit the target. But we can achieve this much, that from a large number of shots the average point of impact will lie in the middle. In contradiction to the deterministic predictions of the older mechanics, quantum mechanics accordingly poses laws which are of a statistical nature.

 

His old friend Einstein was not pleased with the statistical direction physics was taking. “God doesn’t play dice,” he famously scolded Born. Days after Hitler became Chancellor in January 1933 a purge of Jewish teachers began. At Göttingen Franck quickly resigned his post. Born, Courant (head of mathematics) and four other professors were suspended. Born duly was stripped of his doctoral degree and German citizenship. He then took up a three-year lectureship at Cambridge University at a minimal salary and no prospect of a permanent appointment, but eventually accepted a professorship at Edinburgh University. In 1939, with another war looming, he took British citizenship. Eight years after the end of the war, Born, Franck and Courant all were awarded the freedom of the city of Göttingen, which was as much a symbolic gesture, Greenspan observes, to all those who had been exiled (or worse) as much as a recognition of their sheer scientific achievements.

Born and Hedi finally retired to Bad Pyrmont, a spa town near Göttingen. Einstein reacted strongly to the Borns’ return to what he called “the land of mass-murderers of our kinsmen,” a remark that certainly stung Born. But it was at Bad Pyrmont that Born heard that he had won the Nobel Prize. Born told his son, “As I am too old to use the Nobel money for research, I think I will come nearest to Alfred Nobel’s intentions, by attacking the prostitution of science for war and destruction”. For the rest of his life Born actively opposed the use of science for the development of weapons and played a leading part in the founding of the Pugwash movement to make scientists aware of their social responsibilities.