ONE MOVES ALONG IN LIFE, accepting as natural circumstances that to an observer might seem very strange indeed. As I matured in my career, I became focused on my teaching, research and administrative duties, without giving much thought anymore to the bizarre way that I had entered physics. Yet, during the writing of this memoir, I have had to revisit the past and have felt grateful all over again to the great physicists who helped and encouraged me when I was young.
Foremost was Einstein, who simply by writing to me and treating me as an intellectual equal helped me enter academic life and pursue a legitimate path towards becoming a professional physicist and teacher. Our exchange of letters and his views about physics at the end of his life greatly influenced my personal approach to research. Einstein was my first mentor in physics, and I feel that I have been continuing the work that he began and struggled with during his later years for more than fifty years now.
I also owe a significant debt of gratitude to Niels Bohr, Erwin Schrödinger and Paul Dirac for opening doors for me into academia and helping me obtain the financial support I needed for my research. The only “giant” of twentieth-century physics whom I met and write about in this memoir who was less than generous and helpful in my budding career was J. Robert Oppenheimer. Fred Hoyle was open-minded enough to take on a Ph. D. student with my anomalous background. Abdus Salam helped me succeed in earning my doctorate at Trinity College and was confident enough in my abilities that he hired me as his first post-doctoral fellow at Imperial College London.
But more important than these instances of practical help were the lessons I learned from these great physicists. They all, as well as Wolfgang Pauli, demonstrated how to be open to one’s own new ideas in physics, how to do the hard work of formulating those ideas into mathematically rigorous models or theories and then how to defend those ideas and theories when the inevitable criticism from one’s peers rains down.
Some of my mentors I never saw again after their initial positive influence on my life, such as Bohr and Schrödinger. Others, like Dirac and Pauli, I met again over the years. Of all the later meetings with these giants of twentieth-century physics, my last visit with Abdus Salam is particularly poignant. During a summer trip to Europe in the mid-1990s, I decided to visit my old professor at his International Center for Theoretical Physics in Trieste, Italy. One of Salam’s important contributions to physics, aside from his research on the electroweak theory that earned him the Nobel Prize, was establishing this centre for theoretical physics as an intellectual home for scholars from developing countries in Africa, the Middle East and the Indian subcontinent. It had taken Salam’s passion for physics and scholarship, and his concern for young researchers who were not able to advance as easily as those in Europe and North America, to establish this institute and obtain the funding necessary to build it and keep it going. I knew that Salam had been diagnosed with a rare form of Parkinson’s disease, and I wanted to see him one more time while I had the chance.
The institute that had been built in 1968 in the Miramare Park had not changed over the ten or so years since I had last visited. It was an attractive complex, with offices for physicists, a library and space for the administrative staff. Salam had a private dwelling on the grounds, where his second wife, an English biologist, visited him frequently; his first wife travelled between Pakistan and London. The park and institute were located near the main road leading into Trieste, which itself was a charming relic from the Aus-tro-Hungarian Empire.
Salam had a large office on the main floor of the institute. A plaque on its door announced that here was Professor Abdus Salam, Director of the Center. At the time of our appointment, I knocked on the door and a faint voice responded, “Come in.” Upon entering the office, I was surprised to see large, dark footprints painted on the floor, leading from where Salam sat at his desk to the door I had just opened. As we greeted each other, I saw that he had grown much older. His once-gleaming black hair and moustache had turned grey and he looked frail and gaunt. Salam ushered me in with a weak wave of his hand, and I sat down in a chair near him. His arms and hands shook visibly, and he had difficulty speaking, but he managed to rouse himself for my visit. I now understood the purpose of those odd footprints on the floor. They were to help guide him through his office, from the desk to the door. They seemed a dark portent to me.
Salam looked at me gravely and asked, “John, how is your health?” I found this a surprising opening after so many years of not seeing each other, but of course his own health must now be the overriding factor in his life.
“I’m all right,” I said.
“You are fortunate you are in good health,” he said heavily. “As you can see, I am not doing so well.”
We talked about the centre for a while. I wanted to broach the subject of its future, and in particular, who might be taking over when he was no longer able to function as director. However, I felt it would be insensitive to raise this issue, and instead we talked about the daily activities at the institute and what research was being done.
Salam then started discussing his own research, and we got round to talking about his Nobel Prize and his research on the electroweak theory. He said in a somewhat angry tone, “You know, John, after all that’s been done, people don’t believe me. They don’t believe my theory.”
He seemed upset, and it appeared that he was even upset with me. I realized that he may have read a recent paper I had published, in which I had redesigned the electroweak theory without using a Higgs particle, which was central to his and Weinberg’s model.
“Do you believe in my electroweak model?” he asked.
“Well, Abdus,” I began, “I think the basic structure of the theory is correct, particularly now that we know that the W and the Z bosons exist, and there is a need for the neutral Z particle, since they discovered neutral currents at CERN. However, I’m skeptical about the existence of the Higgs particle. As you know, it has some serious problems attached to it, such as the mass hierarchy problem and the cosmological constant problem.”
He looked downcast and asked accusingly, “So you really don’t believe in my model?”
“Well, I don’t know,” I said hesitantly. “In the end, experiment will decide whether or not the Higgs particle exists. However, I’m afraid that we’re more than twenty or thirty years away from solving the mystery of what breaks electroweak symmetry and gives the W and Z bosons and fermions their masses. It might be the Higgs particle, but it might not be.”
Even as I said this, I realized sadly that Abdus was never going to know the answer to this question, which had been so central to his life and work. I wondered whether I myself would live long enough to know the answer. Due to the exorbitantly high cost of building high-energy accelerators able to answer these questions, it would be a long time before these mysteries could be resolved.
“Unfortunately,” I continued, “these days are not like the old days back in the fifties and sixties, Abdus, when we could produce a speculative theory, make a prediction and have it tested experimentally within a few months.”
I then related to him an anecdote about Dick Feynman that I remembered from the sixties, when we were still trying to understand the structure of weak interactions of elementary particles. The U. S. physicists Robert Marshak and George Sudarshan discovered that the weak interactions had to have a vector minus axial-vector (V-A) structure. This technicality has to do with the kind of interactions that occur between elementary particles undergoing radioactive decay. Feynman and Gell-Mann independently discovered this V-A structure at Caltech at around the same time as Mar-shak and Sudarshan. Feynman invited his experimental colleagues to his office one day and excitedly told them that the weak interaction theory had to have this V-A structure: it was elegant and beautiful, so it had to be right! The experimentalists demurred, and told Dick that they had already checked all this out experimentally, and that the V-A proposed by Feynman and Gell-Mann was not the experimentally correct structure.
Feynman said, “Go away and do your experiments again. It’s got to be correct.”
Some months later, his experimental colleagues returned to Feynman’s office and exclaimed, “Dick, you were right! We redid the experiments, and it is V minus A!” It did not take long to vindicate this prediction experimentally, compared to the situation in particle physics today, when it can take decades of effort to verify or falsify a theoretical prediction.
Salam continued to look downcast. I was sorry that I wasn’t cheering him up during this visit. “You’re right,” he said. “The world of particle physics has changed profoundly. It may be that there are some fundamental questions that we can never find the answers to.”
At the end of our conversation, I rose, held his trembling hand and wished him farewell and all the best. He nodded but said nothing. I followed the footprints on the floor, and at the door turned and waved to him with a heavy heart.
Salam died two years later. It turned out that, like so many successful founders of institutes and businesses, he had never groomed anyone to become his successor as director. Yet, after an initial confusing period of time, a new director was found, and the centre continues to fulfill its original purpose today, as the Abdus Salam International Center of Theoretical Physics. As for Salam’s legacy as a physicist, which bothered him during our conversation near the end of his life, we now await confirmation of his elec-troweak theory by the Large Hadron Collider, or evidence that the Higgs particle does not exist and therefore the electroweak theory has to be revised.
I am now in my seventies, several years older than Salam was at our last meeting, and my joy in doing physics has not diminished.
Thinking about how the universe works and how it can be explained by mathematical equations still astonishes and inspires me. My powers of reasoning and the flow of ideas seem to have only strengthened over the years, as so much physics has poured through my brain. I characteristically think laterally, pulling in information and insights from one area of physics or astrophysics to solve a problem in another area. This may help explain why I so often work outside the mainstream box in physics, exploring new ideas.
Looking back on the more than 250 papers I have published in peer-reviewed journals during my career, many were applications of fads and mainstream ideas that have long been forgotten. Who works on Regge poles today? The most important research I have published, which has received the most citations and the most attention within the physics community as well as in the media, has dealt with original ideas often well outside the mainstream of physics, and usually not following the latest physics fad at all— work such as my modified gravity theory (MOG), which has no dark matter, the varying speed of light cosmology (VSL),my void model of cosmology without dark energy and my alternative elec-troweak theory without a Higgs particle.
Often these papers were initially rejected by the established, peer-reviewed journals. Eventually I learned to gauge whether my ideas were possibly paradigm-shifting by noting the intensity of the negative opinions expressed by the referees and the loudness of the opposition of the physics establishment to my papers. There is a herd instinct in physics, as in most academic and scientific fields.
Many hundreds of physicists are waiting for some exciting development within their mainstream activity, and so, when a prominent mainstream physicist publishes a new paper, the herd surges forward in that same direction, even though the idea underlying the new physics fad may not yet be properly thought out or has little possibility of experimental confirmation.
My collaborator Viktor Toth commented recently that there seems to have been an inversion in the age group taking risks and pursuing ideas well outside the mainstream of physics versus staying within the confines of the most recent fad. It used to be that the younger physicists in their day—those that I was privileged to know when they were middle-aged or older—such as Einstein, Heisenberg, Schrödinger, Pauli and Dirac—were the risk-takers. Quantum mechanics, one of the great revolutions of modern physics, was mainly developed by risk-taking young physicists. The older physicists involved in the development of quantum mechanics, such as Einstein, Bohr and Schrödinger, while they did contribute to the early creation of the theory, also played major roles as mentors. There was no draconian peer-review system during the early part of the twentieth century, when the radical quantum mechanics revolution was taking place. The older classical physicists, that is, the rest of the physics community, considered the new quantum mechanics to be incomprehensible and possibly crazy. However, the establishment did not impede the publication and dissemination of the major papers that were the groundwork of the new quantum mechanics.
Thus, unlike many younger physicists today, the younger physicists of the past had more freedom to take risks and publish cutting-edge research; they didn’t worry so much that their papers would be rejected or that they would be denied tenure on the basis of their outside-the-box research interests. And, of course, quantum mechanics was developed by only about ten prominent physicists between 1920 and 1930, and the entire community of physicists numbered only several hundred. Today there are thousands of physicists actively pursuing physics research. Quantity does not necessarily equal quality.
Speaking to a young post-doctoral fellow at the Perimeter Institute recently and explaining my recent radical work in particle physics, he exclaimed that he was not in a position to attempt this kind of research because he had to worry about getting a job and achieving some sense of security so that he could support his wife and children. Another post-doctoral fellow I talked to said that it would be professional suicide for him to work on the type of ideas that I was investigating in particle physics. It should be understood that progress in physics does demand a continuing effort in mainstream physics. However, opportunities for creative young physicists are limited in that often physics departments and laboratories work in large groups, and you are expected to fit in with the group and pursue their goals, which are most often mainstream.
Today I am still as involved in discovering new ideas in physics and cosmology as I ever was. Perhaps the continuing surges of creativity that I experience might stem in some mysterious way from the psychic residues of my traumatic wartime childhood, or from my early ambition to become an artist, discovering and creating beauty. But I feel certain that this ongoing creativity is due in large part to my unusual path in physics. I was never subjected to the severe rigours of rote learning, which students undergo at universities as part of their early training as physicists, and therefore my creative abilities as a human being and a physicist were never quenched. Because I essentially taught myself physics and mathematics, I did not have to prove to the authorities at every step along the way that I was competent in successive areas of physics. My Ph. D. defence was the one exception, and it left a small psychic scar, as well as a trick stomach. But in general, when I was a student at Cambridge, as it was then in the 1950s, I was free to apply the tools I was learning to unlock the secrets of nature that compelled me.
I am grateful to Cambridge University for allowing me to go my own way. I am still enjoying the benefits, and battling with the difficulties, of journeying outside the herd. I am grateful to the generous giants of twentieth-century physics who served as my mentors and showed me the way.