My quest to interview theoretical physicist Peter G. Bergmann
Fourteen years ago, I received a Guggenheim Fellowship to study the history of Einstein’s unification research, especially his higher-dimensional theories. The foundation’s reputation offered me a yearlong ticket to all the archives I could visit and all the interviews I could arrange. In return, my challenge was to reconstruct how the founder of relativity conducted his twilight efforts.
Einstein’s working style suggested whom I ought to contact first. The greatest physicist of the 20th century had taken in his later years to dole all his calculations off to younger researchers. These assistants would meet with him each morning, gauge his opinions on various issues, then spend the rest of the day working out the details. The next day, Einstein would look over the results, frame them according to his own intuitions, then offer further suggestions and so forth.
Undoubtedly Einstein’s former assistants could provide invaluable information about their mentors’ evolving views. Therefore I hoped to reach as many of them as possible and gather their first-hand insights.
The trouble was, almost all of them had passed away. Those remaining were long retired from academic positions, and could likely only be reached at their homes. My reluctance to call famous physicists whom I had never met seemed outweighed by my mission to learn the truth about the past.
A quick internet search revealed the location and phone number of Peter Bergmann, one of Einstein’s best known protégés and a leading physicist in his own right. Known for his pioneering efforts to reconcile relativity with quantum mechanics, as well as his influential textbooks about the riddle of gravitation, Bergmann resided in New York. He lived in an apartment on Riverside Drive, uptown from Columbia. I had never been to his neighborhood, but quickly found it on an MTA map. Soon I had fanciful visions of arranging to rendezvous with him at a local coffee shop and reveling in his tales from the 1930s.
A series of fruitless phone calls put these grand illusions to rest. Bergmann’s number simply wouldn’t answer. I called his former department at Syracuse University and no one seemed to know exactly where he was. Finally, an ex-colleague gave me the bad news — illness had recently forced Bergmann to move to Seattle where he was living with his younger son. He probably wasn’t well enough to talk to me.
Sadly I remembered the advice a physicist friend had offered me. “The 1930s generation is dying off,” he warned. “Waste no time in contacting anyone on your list.”
Several weeks later I found myself in New York to attend a reception for Guggenheim winners. Circumstance placed me near Bergmann’s neighborhood and curiosity steered me to his old building. Well knowing he wasn’t there, I nevertheless thought it would be useful for my project to glean some sense of how he lived.
I walked into a dark, musty lobby that seemed more to me like a utility corridor in a blackout. Could this be the place where Einstein’s prodigious assistant and the founder of the field of quantum gravity spent his final years? A desk clerk assured me it was, and that Bergmann had lived there in fact for almost six decades. The clerk had seen Bergmann almost every day — on the way in and the way out. “We used to chat about Einstein,” the clerk told me. “I called him the guy with the funny hair.”
The clerk went on to describe the day three weeks earlier that Bergmann had moved out of the apartment. Bergmann’s wife Margot, a physical chemist, had died the year before. Married for more than 65 years, the loss had been absolutely devastating for him. Sorrow took its toll on his 87 year old frame and he desperately needed more extensive care. “He was brought out on a stretcher,” the clerk painfully recalled.
As a fan of Bergmann’s extraordinary contributions to gravitational physics, it was wrenching to hear the news. It left me feeling a personal stake in his recovery. I found out his son’s phone number and summoned up the nerve to call him. As I discovered, Bergmann’s condition was complicated. On the one hand, his health was poor and he had little energy. On the other hand, he would briefly seem to perk up on the occasions when he could speak about physics and other matters dear to his heart.
I arranged with his private nurse, Linda Jean Owens, a time to speak with him. She waited until he seemed receptive, then put him on the phone. Given my long wait for an interview and my deep concerns about his welfare, it was thrilling just to hear his voice.
Despite Bergmann’s physical hardships, his German-accented voice that had addressed so many international conferences was still clear and resounding. He soon recalled his research with relativity’s founder more than six decades earlier. “I worked with Einstein for several years,” he recounted.
I asked Bergmann about Einstein’s predilection for playing the violin as a means of relieving the stress of intensive research. Many accounts of Einstein’s work describe him breaking up the tedium of calculations with delightful musical interludes.
“He loved to perform,” Bergmann recalled.
I had dozens more questions to ask Bergmann about the specifics of his search for a unified theory. But the aged physicist cautioned me that it would take too much time to lay out the details. When asked, for instance, about the need for a fifth dimension in such models, he responded, “I think I can’t explain it in two minutes on the phone.”
Sooner than I had hoped, the conservation had reached its natural limit. Bergmann was simply too tired. After he handed the phone back to Owens, I expressed my gratitude for even this brief exchange with such an influential scientific figure.
Owens described how rewarding it was spending time with Bergmann and sharing in his memories. Most of these centered on his beloved Margot, the mainstay of his life and his confidant on scientific matters. “He still mentions her name 5 or 6 times a day,” she reported. “They were extremely close. His wife was sent a set of pictures of them for her 85th birthday. In every picture they were just looking at each other. They didn’t even look at the camera.”
Inspired by this conversation, in subsequent months I took the opportunity, through archival work and interviews, to uncover the forces that shaped Bergmann’s lifelong passions. My work revealed complex influences dating back to the days of the First World War.
Born to a Jewish family in Berlin on March 24, 1915, young Peter was cradled in an ideal setting for scientific education. His father, Max Bergmann, worked in the lab of a Nobel-prize-winning chemist, then went on to found a leading institute for materials research. His mother, pediatrician Emmy Bergmann, was a noted leader in educational reform. Along with her sister, Clara Grunwald, she brought Maria Montessori’s innovative methods to Germany. Consequently, Peter participated in one of the very first Montessori schools, run by his mother, where he demonstrated extraordinary talents in mathematics, science and music. It would be the perfect combination for his later apprenticeship to Einstein.
The same year Peter Bergmann was born, Einstein was putting the finishing touches on his masterful general theory of relativity. Overturning longstanding Newtonian constructs, it boldly envisioned gravity as ripples in the fabric of reality. Though feeling worn out from this endeavor, Einstein knew that he had far more work to do. Gravitation was only one aspect of nature. A true universal theory, he realized, must include all known forces and provide an explanation for atomic behavior.
The nascent field of quantum mechanics, centered in Copenhagen, would soon accomplish this last goal — describing the basic properties of atoms. Revolutionary theories by Niels Bohr and Werner Heisenberg would demonstrate that chance is at the core of all things. Einstein never liked this reliance on probability, famously arguing that “God does not roll dice.” Thus to trump probabilistic quantum theory, Einstein set out to develop a wholly deterministic unified model.
As Einstein searched for order in nature, dark forces gathered that would bring chaos and devastation to Europe. The rise of the Nazis meant that Einstein was a wanted man, and that his theories were verboten in Germany. Fleeing to Belgium, he found a cottage where he could live under the monarchy’s protection while preparing for a life overseas.
Peter was just finishing college when Hitler came to power. Hoping to study relativity, quantum theory and other aspects of modern physics, he saw little chance under the iron hand of the Third Reich. Realizing that her son’s academic career was in danger, Emmy wrote desperately to Einstein asking for his advice. She wondered if he’d be able to take on a promising Jewish lad, head full of scientific ideas, as a student.
Einstein replied that he was in no position to take on any students, but recommended a well-known physicist, Wolfgang Pauli, in Zurich. Zurich was too expensive, however, so Peter boarded the train to Prague where he would study with Philipp Frank.
By that time, the Bergmann family now found itself scattered all over the world. Max, who had divorced Emmy, lost his job and ended up taking a position at what was to become Rockefeller University in New York. Emmy and her sister Clara found that they could no longer operate their Montessori schools. Self-directed, child-centered education ran antithetical to the militaristic Nazi system. After moving back to Berlin, Emmy eventually fled to Palestine. Clara stayed behind and ultimately perished at Auschwitz.
Before it was too late to leave the burgeoning Reich, Peter wrote to Einstein from Prague, asking him again about the prospects for a position. By then, Einstein had found safe haven at the Institute for Advanced Study in Princeton. After consulting with Frank about Peter’s credentials, Einstein replied enthusiastically that he would welcome Peter’s assistance.
Around that time, Peter had met and married Margot Eisenhardt. He had fervently courted her by biking dozens of miles through the Black Forest each time he wanted to see her. At last he had found a companion with whom he could share his scientific interests. In 1936, they set sail for the United States, excited by the prospects of working with Einstein.
When Bergmann arrived at Princeton, he found Einstein a virtual recluse. Einstein’s wife Elsa died in December 1936. Elsa had been Einstein’s social manager, coaxing him to attend public functions from time to time. With her passing, he retreated even further into his private world of equations. No social etiquette stood in the way of his quest for a theory of everything. Hence images of Einstein from his later years depict him with an abundant mane of unkempt hair, a loose sloppy sweater and a pipe.
Einstein had an office in Princeton’s Fine Hall, a grand temple of mathematics with specially designed stained-glass windows etched with various formulae. The centerpiece of the building was a faculty lounge with a large fireplace. Carved above fireplace was an expression the department chairman had overheard Einstein say. Translated from the German it read, “God is crafty but not malicious.”
This engraving aptly expressed Einstein’s beliefs. Although he was not at all religious, he felt that God designed the universe according to subtle, but potentially discernable, rules. The job of Bergmann and his other assistants was to cut through the mathematical underbrush and reveal possible paths to the true universal model.
Bergmann greatly admired Einstein’s resilience. If a path proved a dead end, Einstein would not hesitate to suggest a novel avenue of exploration. Former views would quickly be forgotten, replaced by an unbridled enthusiasm for the new method.
As Bergmann once explained to historian John Stachel. “There was always a first phase [of developing a unified field theory] when Einstein was very uncritical. Then, like a gardener, he would pick up the plant and look at its roots. After examining it closely, he would then have a more critical attitude. A few days later he would have a new theory. He would progress through these moods — uncritical, then self-critical, then uncritical — again and again.”
Whenever Einstein’s assistants became discouraged, he urged them to be patient. The world has waited such a long time already, he counseled them, a few more months won’t hurt.
Bergmann frequently worked with another assistant, Valentine Bargmann. Because of their curiously similar surnames, Einstein’s secretary nicknamed them “the Berg and the Barg.” Often, Bergmann and Bargmann would shadow Einstein as he walked to and from his office.
Einstein and his various assistants published a number of papers together, many of them incomplete attempts at unification. Remarkably, given his hallowed reputation, these articles were little-read. The world had entered the nuclear age and the physics community had more pressing matters to consider.
After his four-year apprenticeship was over, Bergmann joined the faculty of Black Mountain College, an experimental institution in North Carolina. There he penned his magnum opus, the first complete textbook on relativity, still considered one of the best introductions to the field. An entire generation of physicists drew on it like holy writ for their essential information about gravitation and other phenomena. As a bonus, it contained a superb review of unified field theories to date.
In 1947, the Syracuse physics department offered Bergmann a permanent position. Meanwhile, his wife had found a job at Brooklyn Polytechnic College. Given the hundreds of miles between the two positions, they were faced with the infamous “two-body problem:” to maintain independent academic careers, where should the two of them live?
They reached a rather unusual arrangement. During the weekends they would reside together in a Manhattan apartment (the one on Riverside Drive). Then, for several days a week, Peter would commute to Syracuse, where he had a second place to stay. Margot, in the meanwhile, would watch their children and take the far shorter commute to Brooklyn. For decades, they maintained this rather grueling arrangement, by train and then by plane.
At Syracuse, Bergmann established the leading American center for gravitational research. Under his guiding influence, Einsteinian general relativity grew into a distinct and important endeavor, pursued by physicists around the world. He wanted to do much more, however, than promote the ideas of Einstein. To make his mark, he knew that he would need to sever his strong philosophical ties with his mentor.
Bergmann began to pursue the integration of probabilistic quantum theory into general relativity, precisely the sort of “dice-rolling” that Einstein disdained. In a pivotal article, he outlined how Einstein’s theories would need to be re-arranged in order for them to be more amendable to quantum concepts. Predicably, Einstein was uninterested in this endeavor. “You are now on your own,” Einstein told him, then wished him well.
Bergmann however was exhilarated by his new project. As Josh Goldberg, one of his colleagues has said, “Peter inscribed his first paper with his white marker: ‘Dearest Margot, with great love. It may be self-serving, but this is the first work of which I am myself proud.’ With these words he left behind the prejudices of his mentor.”
Remaining at Syracuse until his retirement, Bergmann then took a post-retirement position at New York University. His close friend, physicist Engelbert Schucking, offered him desk space and invited him to participate in seminars. He kept up his research interests well into his 80s. As a fitting crown to his career, the American Physical Society awarded him its inaugural Einstein Prize, which he shared with esteemed physicist John Wheeler.
On October 19, 2002, several months after I spoke with him on the phone, Peter Bergmann died. Although I never had the chance to speak with him again, I felt that I had come to know him well through the warm recollections of his family and friends, as well as the letters, books and papers that he left behind. As the number of living witnesses to Einstein’s work dwindles, each personal testimony grows far more precious.
Originally published at www.pachs.net.
Paul Halpern is the author of Einstein’s Dice and Schrödinger’s Cat: How Two Great Minds Battled Quantum Randomness to Create a Unified Theory of Physics.