50 Feynman’s drawing is reproduced in the frontispiece of Kursunoglu and Wigner (1987). An example of Feynman’s ‘I’m no Dirac’ is in interview by Charles Weiner of Richard Feynman, 28 June 1966, p. 187 (CALTECH).
51 Lord Waldegrave points out that ‘the award was largely the result of the intervention of Victor Rothschild, the late Lord Rothschild, who was well placed at that time as a Permanent Secretary in the Cabinet Office as Head of the Central Policy Review Staff of Prime Minister Edward Heath’ (interview with Lord Waldegrave, 2 June 2004).
52 Letter from Manci to Barbara Gamow, 1 May 1973, LC.
53 Salaman and Salaman (1986: 70). Dirac raised this issue in the context of the experience of his daughter Monica, who ‘had studied geology but had given it up to look after her baby’.
54 Interview with Mary Dirac, 21 February 2003.
55 Interview with Leopold Halpern, 18 February 2003.
56 The British part of the project was eventually delivered by the British Aircraft Corporation in collaboration with the French company Sud Aviation, following an agreement signed in 1962. The British Aircraft Corporation had been formed in 1960 from the Bristol Aeroplane Company and other aeronautical firms. I thank Andrew Nahum for advice on this.
57 The Diracs flew from Dulles to Paris on 5 May 1979 (DDOCS). Letters to Dirac from Abdul-Razzak Kaddoura, Assistant Director-General for Science at UNESCO, dated 29 March 1979, are in Dirac Papers, 2/9/3 (FSU).
58 New York Times, 5 May 1979.
59 A copy of the speech is in Dirac Papers, 1/3/8 (FSU).
60 Kapitza wrote to Dirac on 18 February 1982, ‘Knowing of your going will certainly stimulate my travelling,’ Dirac Papers, 2/10/6 (FSU).
61 A recording of Dirac’s 1982 talk to the Lindau meeting, ‘The Requirements of a Basic Physical Theory’ (1 July 1982), and other details are available at LINDAU.
62 Details of the accommodation are in Dirac Papers, 2/10/7 (FSU).
63 Interview with Kurt Hofer, 21 February 2004; interview with Leopold Halpern, 26 February 2006.
64 Dirac gave this lecture on 15 August 1981, Dirac Papers, 2/29/45 (FSU).
65 The Erice Statement is readily available on the internet.
66 On 7 December 1982, Dirac wrote to the Master of St John’s to apologise for not being able to attend a gathering at college on 27 December to toast Dirac’s health in his eightieth year: ‘For 59 years, the College has been the central point of my life and a home to me’ (STJOHN).
67 Interview with Peter Goddard, 7 June 2006.
Twenty-nine
I bade, because the wick and oil are spent
And frozen are the channels of the blood,
My discontented heart to draw content
From beauty that is cast out of a mould
In bronze, or that in dazzling marble appears,
Appears, but when we have gone is gone again,
Being more indifferent to our solitude
Then ’twere an apparition. O heart, we are old;
The living beauty is for younger men:
We cannot pay its tribute of wild tears.
W. B. YEATS, ‘The Living Beauty’, 1919
The confidence Dirac displayed when he spoke about physics hid a despair that he apparently revealed only once, to someone he hardly knew – Pierre Ramond, a theoretical physicist at the University of Florida in Gainesville.1 A courteous and articulate man, Ramond is an American who speaks in a richly musical voice whose accent is a constant reminder to his listeners that he was born and raised in France. After lunch one Wednesday in the early spring of 1983, he drove from Gainesville to give a colloquium at Florida State University, hoping that his ‘hero and guiding light’ Dirac would be in the audience. Sure enough, when Ramond arrived in the seventh-floor seminar room, overlooking the campus, he saw in his audience the daydreaming figure of Dirac, slight as a pixie.
In his presentation, speculative but assured, Ramond discussed the possibility of setting out fundamental theories not in the usual four dimensions of conventional space-time but in a higher number of dimensions.2 Throughout, Dirac appeared to be snoozing, and, during the questions afterwards, he said nothing. But when the seminar broke up, he – unusually – lingered until he was with the speaker, alone, and the door was shut.
Ramond had met Dirac twice before, but had not been able to draw him into anything resembling a normal conversation. ‘I had heard that the only way to persuade Dirac to talk was to ask him a non-trivial question that required a direct answer,’ Ramond recalls. So he asked Dirac directly whether it would be a good idea to explore high-dimensional field theories, like the ones he had presented in his lecture. Ramond braced himself for a long pause, but Dirac shot back with an emphatic ‘No!’ and stared anxiously into the distance. Neither man moved, neither sought eye contact; they both froze in a silent stand-off. It lasted several minutes. Dirac broke it when he volunteered a concession: ‘It might be useful to study higher dimensions if we’re led to them by beautiful mathematics.’ Encouraged, Ramond saw an opportunity: doing his best to sound understanding, he invited Dirac to give a talk on his ideas at Gainesville any time he liked, adding that he would be glad to drive him there and back. Dirac responded instantly: ‘No! I have nothing to talk about. My life has been a failure!’
Ramond would have been less stunned if Dirac had smashed him over the head with a baseball bat. Dirac explained himself without emotion: quantum mechanics, once so promising to him, had ended up unable even to give a proper account of something as simple as an electron interacting with a photon – the calculations ended up with meaningless results, full of infinities. Apparently on autopilot, he continued with the same polemic against renormalisation he had been delivering for some forty years. Ramond was too shocked to listen with any concentration. He waited until Dirac had finished and gone quiet before pointing out that there already existed crude versions of theories that appeared to be free of infinities. But Dirac was not interested: disillusion had crushed his pride and spirit.
Dirac said goodbye and walked off, looking impassive, but Ramond was shattered. He took the elevator to the ground floor and walked alone in the fading light of the afternoon back to his car. Twenty-five years later, he could still recall how upset he was: ‘I could hardly believe that such a great man could look back on his life as a failure. What did that say about the rest of us?’
Ramond cannot recall whether he had explicitly mentioned to Dirac the idea that nature is fundamentally built not of point-like particles but of tiny pieces of string. In the late 1970s and early 1980s, Ramond was one of the small band working on the idea, then a backwater of theoretical physics. Dirac had tentatively suggested in 1955 that electrons and other quanta might be pictured as lines rather than points, but the mathematical form of Dirac’s idea was completely different to that of the modern string theory, itself still only embryonic. The theory had, however, used contributions Dirac had made in the late 1950s and early 1960s, including his methods of describing two-and three-dimensional objects in ways consistent with both quantum mechanics and the special theory of relativity. The mathematics he used to describe a small sphere – his model of a muon – resurfaced in a different context, to describe the motion of a string moving through space and time.
Among the encouraging features of the new string theory was a pleasing absence of the infinities of conventional field theories, such as quantum electrodynamics, the best-available description of electrons and photons. Most impressive was that string theory made the existence of gravity inevitable: if the theory is correct, gravity must exist. Although there was no experimental evidence to favour string theory over other field theories, to its supporters it looked too beautiful to be entirely wrong. Dirac will have heard about the theory in seminars at Florida State but he gave it no credence – his curiosity was spent. A few months after his eightieth birthday, the local journalist Andy Lindstrom had found him ‘a painfully spare man […] stoop-shouldered and frail’. His once-black h
air had ‘retreated to a wispy cowl at the very fringes of his forehead, as though worn away by the great thoughts fermenting below … A web of wrinkles etches his gentle, lonely face, outlining eyes that seem to be forever questing.’3
Since overcoming his digestive trouble in late 1980, Dirac had become more relaxed about his health, but his anxieties returned three years later when he started to suffer from apparently unrelated problems – night sweats and occasional fevers. He consulted Hansell Watt, a local doctor and lay preacher whose calm, comforting words were all the more reassuring for being spoken with a rich southern drawl. Dirac took to him, and, for Manci, he could do no wrong. Watt diagnosed the source of Dirac’s medical problems to be his right kidney, which X-ray photographs showed to have been infected by tuberculosis, probably when he was a child. This was a surprise to Dirac, who had never suspected that he had been infected, having been assured by his mother: ‘T. B. runs in families and it is absolutely not in ours.’4
When Dr Watt advised Dirac that his tubercular kidney should be removed, Halpern was outraged.5 Wary of surgical cures and wanting only to try herbal remedies, Halpern opposed Watt’s strategy and – to Manci’s anger – did all he could to undermine it. Manci, fighting Halpern’s influence over Dirac like a tigress guarding her wounded cub, did not tell him when she arranged the operation at the Tallahassee Memorial Hospital on 29 June 1983, a month after what would be his final talk.6 The surgeon found that Dirac had only the last remains of a right kidney with a cyst the size of a hockey ball.7
The operation was technically successful but it left Dirac an invalid. Weak and dispirited, he spent the summer recuperating at home, watching television and playing Wei Chi and other board games but unable to do serious work. After several weeks, he could walk a few steps but did not have the strength to venture out of his air-conditioned home into the heat and humidity outside. For the first time in decades, he could not spend the summer walking in the countryside – especially cruel for someone who had trodden a distance comparable with Wordsworth’s total of about 180,000 miles.8 One of Dirac’s most frequent visitors was Halpern, who sat at his bedside several times a week, chatting about their work and anything else that took their fancy, including politics. Dirac said that he could not help liking President Reagan, though he disagreed with most of his policies; at heart, Dirac remained a liberal, though with no loyalty to the Democrats or any other political grouping.
Halpern’s relationship with Manci became more fraught by the week. Upset by what he saw as her unending nagging, he often found himself leaving the Diracs’ home red-faced and purse-lipped with anger. Whenever Dirac mentioned his discomfort at Tallahassee’s oppressive summer climate, she would shoot back with her favourite rejoinder, ‘It’s better than Cambridge,’ Halpern recalled.9 For her part, Manci thought Halpern was a rude, interfering busybody who was shamelessly taking advantage of his helpless friend by foisting quack medicine on him. Aware of her hostility, Halpern decided that subterfuge was the only hope. When Manci was out shopping, he instituted a secret programme of homoeopathic treatment, furtively dropping herbal essences into Dirac’s drinking water when the nurse was not looking.10 According to Halpern, Dirac’s energy resurged like Popeye’s after he had downed a can of spinach. As soon as Manci found out about ‘the herbal conspiracy’, she returned Dirac to his usual diet, whereupon he slipped back into lethargy and indifference, if Halpern’s testimony is correct.
Dirac spent most of his waking hours in a wheelchair, talking to visitors, including his daughter Mary and her dashing new husband, Peter Tilley. After a few months, Dirac was fit enough to return occasionally to his office in Florida State University, to supervise his final graduate student Bruce Hellman and to oversee what would be his final publication. Halpern drafted the text of ‘The Inadequacies of Quantum Field Theory’ for Dirac, who wanted his final published words to execrate renormalisation, the technique born of one of his most profound contributions to science.11 For the last time, he refused to accept that, as Feynman had advised him in 1946, he was on ‘the wrong track’. Feynman might as well have counselled a train to depart from its rails.
Early in April 1984, Dirac heard that Kapitza was dead. The Soviet Union knew it had lost one of its most loyal subjects: the entire Politburo and many of the country’s scientific leaders signed Pravda’s announcement of his death. Dirac had lost his dearest friend, his surrogate brother, but he showed only resignation. More sad news followed a few weeks later: the Diracs’ son Gabriel had a skin cancer so aggressive that his doctors gave him only a few months to live. In June, Manci flew to Europe to see her son, leaving Dirac in the care of friends. A few weeks after her return, Gabriel died on 20 July, aged fifty-nine. Three days later, Dirac was too ill to put himself to bed.12 Halpern was away in Europe, so Manci had her husband to herself and had to cope with his sinking morale and hardening stubbornness.13 Dirac’s spirits rallied during a visit by Gabriel’s daughter Barbara, a radiantly attractive young woman and a special favourite of the Diracs. (‘You look like Cher,’ he told her a few years before.14) In sharp contrast to Halpern, Barbara’s view of Manci was that she was a sensitive and humane nurse – there were occasional quarrels between her and Dirac but they would dissolve swiftly into an affectionate holding of hands. Dirac’s energy had all but ebbed away, Barbara observed, but his love of physics still flickered: he returned to his papers and whispered resolutely, ‘I have work to do.’15 His greatest fear, of losing his mind, was never realised.
At the beginning of October 1984, after Barbara had returned to Europe, Manci hired nurses to be with Dirac round the clock: he was hanging on to the last thread of life. But he still received the occasional visitor, including Mary’s husband Peter Tilley, who sat for hours at Dirac’s beside, mostly in silence. During his final visit, Tilley recalls, Dirac leant over to him and said firmly, in a matter-of-fact tone: ‘The biggest mistake of my life was marrying a woman who wanted to get out of the house.’16 Dirac sounded neither bitter nor regretful, Tilley remembers, but was making a factual statement in a way that invited no further discussion. Perhaps Dirac was thinking of what Manci had said to him soon after they met – that she had married her first husband only to get out of her parents’ home – and of the veiled warnings his mother had given him about marrying Manci forty-seven years before.
The battle of wills between Manci and Halpern resumed. When he knew she was out, Halpern sneaked into the house and stirred his fortifying herbs into Dirac’s drinking water. The nurse had almost given up trying to interest him in food, and it was left to Halpern to feed his friend, who took his food like a baby. All Dirac wanted to do was to talk about Kapitza. Dirac spent many of his last conscious hours recounting favourite stories about his friend’s colourful life – over and over again, Dirac told the story of how Kapitza refused to work on the bomb, standing alone among lesser mortals who did not have the moral courage to make a stand. It was a tape loop of delusion.
On Thursday 18 October, as Halpern was leaving the Diracs’ home, he bumped into Manci. He was expecting a telling off for visiting his friend, but Manci did not mention it; she told him calmly that she had just been to the mortician to reserve Dirac’s grave. But the next day Halpern received the phone call he had feared for weeks: Manci forbade him from setting foot in the house again – Dr Watt had told her, she said, that Dirac was too weak to see anyone except close family. Angry, bitter and tearful, Halpern heard nothing until four days later, when he read on the front page of the Tallahassee Democrat: ‘FSU physicist is dead at 82’. On the Saturday evening, with Manci and his nurse at his side, Dirac’s heart had failed and stopped beating at five minutes before eleven.17
‘I want to be put down like a horse,’ Manci told Dr Watt. But in public she showed her usual spirit and fortitude, informing friends and relatives of Dirac’s passing with business-like calm and attending to every detail of the funeral arrangements.18 She took great pains to ensure that Dirac was remembered as she wanted: the da
y after his death, she told friends that he was ‘a very religious man’ and that he would have wanted a high-Episcopalian funeral.19
The ceremony took place in the open air at the Roselawn cemetery in Tallahassee, on 24 October, under an overcast sky, rain threatening. When the guests arrived, shortly before 11 a. m., they saw Dirac’s coffin was on a plinth beside his freshly dug grave, under a bright blue marquee-like roof mounted on four wooden poles, in the shade of a group of conifers swaying slightly in the breeze. Among the mourners was Dirac’s one-time confidant, Pierre Ramond, who was surprised when he saw the congregation: ‘Considering how famous he was, there were very few people there.’20 There were about ninety mourners, including dozens from Florida State University but – as Manci bitterly noted – no one from Cambridge. Several in the congregation were uneasy to see that they were not alone: they had been joined by scribbling journalists and a flotilla of television crews. Manci had decided that her husband should be buried under the encircling gaze of TV cameras.21
The rector Dr W. Robert Abstein read slowly from the oldest-surviving version of the Anglican Bible, the text Manci had insisted on. She had forbidden Halpern to speak, and there was no eulogy. After half an hour, as the sky brightened, Abstein crumbled soil on the coffin and traced the sign of the cross in the dirt. The place of Dirac’s burial was marked a few weeks later with a neat white-marble stone, engraved with words he had used, chosen by Manci: ‘because God said it should be so’.
A few days after Dirac’s funeral, Manci had to take another blow. She heard from the police in Vermont that they now presumed that Judy was dead and that they had called off the hunt for her.22 The pain for Manci was terrible: in just four months, she had suffered the grief of losing her best friend in Russia, two of her children and her husband. Life seemed to hold little for her – but she was a fighter.
The Strangest Man Page 60