The Strangest Man

by Graham Farmelo

  By the way, will you try and not forget all your Russian in the barbarous United States. Please try and read a little from time to time. […] And do remember what I told you about not marrying an American: it would be a fatal mistake! An English girl, of firm but tactful disposition will be most suitable for you. As for a Russian – they are a handful under any circumstances […]. 16

  Determined that no one else would read Dirac’s letters to her, she routinely burned them. Their opinions about the Soviet Union, as well as the evidence of whether the relationship became physically intimate, were probably destroyed in those flames.17

  Dirac arrived in Princeton at the end of September, after another hiking vacation with John Van Vleck, this time in the mountains of Colorado.18 Once again, Dirac provided his friend with more stories of his strangeness, including one in Durango where he was wandering around the town at night, probably wearing what might be kindly described as functional clothing, and was mistaken for a tramp. This would not be the last time Americans would mistake the Lucasian Professor for a vagrant.

  In Princeton, Dirac was working at the Institute for Advanced Study, then a suite of offices in Fine Hall. He and his colleagues in Fine Hall liked to eat at one of the modest restaurants in Nassau Street, the rod-straight road that separates the university buildings on one side from the shops on the other. A faculty favourite was the Baltimore Dairy Lunch, known locally as the Balt, which served wholesome food at low prices, though only to white customers.

  One of Dirac’s preferred dining companions was his new colleague Eugene Wigner, the courtly Hungarian who was on a mission to bring modern quantum mechanics into Princeton. Inexplicably parsimonious, he declared proudly to visitors to his two-bedroom apartment that its furnishings had set him back less than $25, as if it were not obvious.19 On the day after Dirac arrived in Princeton, neither Wigner nor any other Fine Hall colleague was free for lunch, so Dirac set off alone on the five-minute walk into the town centre. When he entered the restaurant, probably the Balt, he saw Wigner sitting with a woman.20 Well-groomed and slightly younger than Wigner, and with an infectious cackle of a laugh, she looked rather like him, her face similarly long and angular. She spoke faltering English with the same thick accent, though with none of his reserve, and smoked her cigarettes using a long black holder.

  The woman was Wigner’s sister Margit, known as Manci to her friends and family. She was struck by the sight of the slender, vulnerable-looking young man who walked into the restaurant, later remembering that he looked lost, sad and disconcerted. ‘Who is that?’ she asked her brother. Wigner told her that he was one of the town’s most distinguished visitors, one of the previous year’s Nobel laureates. When he added that Dirac did not like to eat alone, she asked, ‘So why don’t you ask him to join us?’ Thus began a lunch that changed Dirac’s life. His personality could scarcely have contrasted more sharply with hers: to the same extent that he was reticent, measured, objective and cold, she was talkative, impulsive, subjective and passionate – she was the kind of extrovert Dirac liked. They occasionally had dinner together but were not officially dating, perhaps partly because he was distracted by Rho Gamow, who was staying in Princeton, having been left in the care of Dirac by her evidently trusting husband.21 But these social matters were a sideline: he spent most of his time hard at work in his office in Fine Hall and in the rooms he rented in a grand house on one of the leafy avenues close to Nassau Street.22 So far as his colleagues could see, for all the interest he showed in women, he could have been a eunuch.

  In Fine Hall, Dirac was accommodated on the same corridor as Einstein, their offices separated only by Wigner’s. Einstein was the town’s most famous celebrity, after Veblen the first faculty member of the institute. He and his wife had arrived in October 1933 and lived in an apartment before settling in a modest detached house in Mercer Street, about five minutes’ walk from the centre of the town, which he described as a ‘quaint ceremonious village of puny demigods on stilts’.23 Although grateful to be in a safe haven and ‘almost ashamed to be living in such peace while all the rest struggle and suffer’, he could see his new home town was not free of racism and may have discussed this in his meetings with Paul Robeson, the town’s most famous son.24

  Then fifty-four, Einstein looked older: he shambled around the town in his plain raincoat and woolly hat, avoiding eye contact with fellow pedestrians, especially ones who recognised him.25 On the day he arrived in Fine Hall, newspaper photographers and a crowd of hundreds gathered to catch a glimpse of him through an open library window. The authorities had to smuggle him in and out of the hall through a back entrance.26

  Veblen and his colleagues were licking their lips at the thought of Einstein and Dirac working together, but it soon became clear that this was only a dream. The two men respected each other, but there was no special warmth between them, no spark to ignite collaboration. They were studying the same subject, but their approaches were quite different: Dirac was developing quantum theory and was deaf to its alleged philosophical weaknesses; Einstein admired the success of the theory but mistrusted it (during the spring of 1935 he completed his collaboration with his younger research associates Boris Podolsky and Nathan Rosen on a paper that cast serious doubts on the conventional interpretation of the theory).27 Whereas Einstein was a conservative scientist, Dirac was always ready to discard well-established theories, even ones he had helped to create. Language was another barrier: with only weak English, Einstein preferred to talk in his native tongue, which Dirac spoke only with difficulty (in the company of refugees from Hitler’s regime, Dirac relaxed his rule of not speaking German). And Dirac tended to avoid smokers, although Einstein temporarily removed that barrier in late November when he gave up his pipe for a few weeks, to demonstrate his willpower to his wife, who disapproved of the habit. ‘You see,’ he complained to a neighbour, ‘I am no longer a slave to my pipe, I am a slave to dat vooman!’28

  Dirac spent much of this sabbatical writing the second edition of The Principles of Quantum Mechanics, making it less mathematical and less intimidating. The completed version preserved the structure of the original and was more accessible than the first edition, though for all but the most gifted students it was aspirational reading. Most students who wanted to use quantum mechanics to do actual calculations used more practically minded texts, secure in the knowledge that the underlying beauty of the subject was nowhere clearer than in this book, sometimes described as ‘the bible of modern physics’.29

  Still believing that mathematics offered the royal road to the truth about the fundamental workings of nature, Dirac spent much of his time in Princeton learning more mathematics. This led him to find a new way of writing his equation for the electron, by describing its behaviour in a space-time whose geometry is not the standard Euclidean type (in which the sum of the angles of a triangle is one hundred and eighty degrees) but is of a more exotic variety developed by the Dutch mathematician Wilhelm de Sitter. Perhaps this would enable the quantum theory of the electron to be harmonised with the general theory of relativity? The result was a sumptuous piece of mathematics, though one that failed to yield new insights into nature. Dirac had yet to show that his idea – that fundamental physics could be gleaned from promising mathematics – was fertile. No other leading theoreticians had taken much notice of it: they remained pragmatic, taking cues from experiment and trying to learn from the weaknesses and loose ends of the best-available theories.

  One of the most intriguing topics for theorists was radioactive beta decay, in which an unstable nucleus spontaneously ejects a high-energy electron. Early in 1934, Fermi underlined his talent as a theoretician once again, this time by setting out the first quantum field theory of beta decay and giving a clearer understanding of the role of the neutrino. He gave a clear mathematical description of how an atomic nucleus undergoes beta decay, one of its neutrons transmuting into a proton, which remains in the nucleus, while two other particles – an electron and a massless neutrino
– are simultaneously created and ejected. This decay was caused by the weak force, a previously unidentified type of force that acts only over extremely short distances, unlike the familiar forces of gravity and electromagnetism. Although Dirac admired Fermi’s theory, he did not follow him into the nucleus and its complexities. Dirac was adamant that the best way of making progress was to focus on nature’s simplest particles, taking inspiration from the most beautiful mathematics. Time would decide whether such purism was wise.

  *

  Dirac’s colleagues in Fine Hall saw that his fanatical dedication to work was on the wane. He spent most afternoons playing games in the two common rooms, each of them furnished in the style of the best-appointed Oxford University common rooms – plush curtains framing every window, deep-pile carpets on the floor, capacious leather armchairs and imitation-antique tables.30 During the ritual of afternoon tea, he fruitlessly searched for a way that a king could pass eight opposing pawns and got thrashed by his colleagues in their favourite game, Wei Chi (also known as Go), which he had introduced into Fine Hall a few years before.31 He was relaxed enough to channel some of his intellectual energy away from the toughest problems in science to games that had no point beyond personal pleasure. The impasse in quantum electrodynamics appears to have sapped his morale: he may have feared that he had fallen victim to the alleged ‘Nobel disease’, said to prevent prize-winners from repeating the quality of their best work after their return from Stockholm.

  Over ice-cream sodas and lobster dinners, Dirac’s friendship with Manci deepened.32 She was a lively, big-hearted conversationalist, and, although she often struggled to find the right words in English, she had the rare ability to make him thaw. Between the long – but gradually shortening – silences, he told her of the pain of his youth, of his brother’s suicide, of the father whom he believed had tyrannised him into his defensive silence. Manci also had plenty of private unhappiness to share, telling him that she was an unwanted child, less attractive than her sister, intellectually worthless compared with her brother. Mainly to get out of her parents’ house, she married when she was only nineteen. Her Hungarian husband, Richard Balázs, turned out to be a playboy and philanderer, and the marriage was an eight-year calamity mitigated only by the birth of her son Gabriel and daughter Judy. She took the bold step of instigating divorce proceedings and had finally become single again two years before she set sail for Princeton.33 There had been other men after Balázs, but none of them were around for long, and she was lonely and unfulfilled.34 She was staying with Eugene for a change of scenery, having promised her children – in Budapest with their governess – that she would be home for Christmas. At thirty years old, she had never felt so free in her life.

  Although a self-declared ‘scientific zero’, Manci took a lively interest in international ethics, morals and politics, often impressing experts with her knowledge but at the same time affronting them with her shameless lack of objectivity. Once she had made up her mind, facts alone were rarely enough to budge it; she seemed to think not just with her brain but with her heart. Religion caused her special anguish. Until 1915, when she was eleven, her family had subscribed half-heartedly to the Jewish faith, visiting the synagogue twice a year, but then had become Lutherans.35 By the time she met Dirac, she was no longer devoutly religious but appears to have somehow yearned to believe in some kind of deity and did not like to hear religion slighted. She would probably not have welcomed Dirac’s view that his religion was simply that ‘the world has to improve’.36

  Manci was a keen follower of the arts, and she chivvied Dirac into taking more interest in music, literary novels and ballet. In the evenings, like many people during the Depression, they joined the long cinema queues ready to pay their quarters for a few hours’ harmless escapism. They may well have seen some films featuring one of Hollywood’s new stars, Cary Grant, rapidly establishing himself as a versatile actor with a gift for playing both comedy and – having thoroughly suppressed his Bristol vowels – the charming, all-American gentleman.

  About ten days before Christmas 1934, during a journey on the New York subway, Dirac read an unexpected and chilling piece of news.37 He was in the city to buy an overcoat, to replace the one he had given Tamm fifteen months before. Dreading the Christmas throng of Manhattan and its noisy, bullying traffic, he did not hesitate when Manci offered to go along to keep him company. They agreed to meet in Fine Hall, before driving to Princeton Junction, where they would catch the train to Penn Station. After arriving first at the hall, she took a moment to look in his mailbox and found an airmail letter, which she hurriedly put in her handbag and forgot in the excitement of what was her first trip to the shopping capital of America. When she was sitting next to Dirac in a subway car, clattering and squealing its way towards the Midtown stores, she opened her bag to look for a handkerchief and saw the envelope, which she handed to Dirac. It was from Anna Kapitza in Cambridge, he saw, but it was not just another family chronicle. Manci watched Dirac as he read the typewritten letter, a little over a page long. He turned to her with alarming news – the Soviet Government had detained Peter Kapitza in Moscow.

  Anna was desperate. She wrote that her husband’s detention was ‘a terrible blow to him, almost the severest he ever had in his life’, and she pleaded with Dirac for help:

  I am writing to you as a friend of K and of Russia and you will understand the impossible situation […] People will talk and the last thing I want is the press to get hold of it. […] I wonder if you could write a letter to the Russian Ambassador in Washington, I feel that is the only way to do anything […].38

  Earlier, Kapitza had boasted that he was the only Soviet citizen who had unrestricted passage across his country’s borders.39 He had scoffed at his colleagues’ warnings that he was courting disaster by returning home each summer for his vacation. Irritated by the defection of Gamow and other Soviet scientists, Stalin’s authorities were determined to secure the country’s best brains to help build its future. During a trip to the USSR in late September with his wife and children, officials in Leningrad told Kapitza that he must stay in the Soviet Union for the foreseeable future, though his family was free to return to Cambridge. Furious, Kapitza tried to talk his way out of it, pleading unsuccessfully that he could not break faith with his colleagues in England, and was dispatched to Moscow, where he lived in a sparsely furnished room at the Hotel Metropole, with little to do except read, write desperate letters to Anna and go for walks – always under the surveillance of the security police.40 Rutherford and the Foreign Office had kept the matter secret, in the hope that his detention could be resolved diplomatically.41 No one, certainly none of the officials in the security services, had expected this: not for want of trying, MI5 had not found any hard evidence that he was a spy.

  Dirac was still digesting the news when he was trying on overcoats in Lord and Taylor, one of the exclusive stores on Fifth Avenue. Manci had an uphill struggle to persuade him, devoid of dress sense, to take the purchase of the coat seriously. No doubt seeing an opportunity to refurbish his entire wardrobe, the salesman asked Manci discreetly whether Sir would also like a new suit, but Manci smiled and shook her head: to press him to buy more than he needed would be futile. The coat he bought there turned out to be a good investment – it lasted him to his death, a memento of the day he heard about Kapitza’s plight and was moved to take political action for the first time in his life. Though he knew that he had none of the interpersonal skills and tact needed to be an effective diplomat, he became the de facto coordinator of the American-based campaign for Kapitza’s release.

  In Princeton the next day, Dirac urgently sought advice from the well-connected Abraham Flexner and from Einstein, who promptly agreed to help. Dirac was confident enough to write to Anna Kapitza in Cambridge to assure her that matters would ‘all come right in the end’.42 After the Christmas vacation, he would begin his campaign for Kapitza’s release, but first he wanted to take a vacation in Florida. He was planning
to go on his own, but Manci had other ideas: seeing an opportunity to spend some time alone with her new friend, she postponed her return to Hungary until after Christmas, breaking the promise she had made to her children.

  Dirac and Manci motored down in early January from freezing Princeton to the warmth of St Augustine, a resort on the north-east coast of Florida. No one – except, possibly, Wigner – knew that they were together. The vacation appears to have been platonic. Their letters before and after the trip show that they were not yet close and still viewed each other differently – he regarded her only as an agreeable companion, but she saw him as a potential husband. They spent their week dodging the rainstorms and taking trips to the local tourist destinations, including a farm where Dirac spent a few dollars buying a baby alligator that he mailed anonymously to the Gamows in Washington, DC.43 As Rho opened the package in their hotel room, the alligator jumped out and bit her hand – one of her husband’s less amusing practical jokes, she thought. Gamow protested that he had nothing to do with the prank; he thought it was a crocodile, a symbol of his favourite experimenter, sent by someone with more playfulness than common sense. A month later, Dirac owned up, and the poor alligator languished, and a few months later died, in the Gamows’ bath.