Bohm, David Joseph
Bohm, David Joseph
BOHM, DAVID JOSEPH
(b. Wilkes-Barre, Pennsylvania, 20 December 1917; d. London, United Kingdom, 27 October 1992)
theoretical physics, quantum mechanics, philosophy of physics.
Among the first generation of American physicists to receive his advanced training in the United States, Bohm initially distinguished himself with his work in plasma physics. It is, however, his work in quantum physics and his attempt to develop an alternative to the standard interpretation of quantum mechanics for which he is most remembered in the early twenty-first century. His work on more esoteric philosophical matters, beginning in the 1960s, attracted a substantial group of admirers for whom the details of his work in physics were of lesser importance.
Early Years and Education. David Joseph Bohm was born on 20 December 1917, the eldest child of Eastern European Jewish immigrants, Samuel and Frieda Bohm, in the Pennsylvania mining town of Wilkes-Barre. Although Samuel enjoyed success as a small businessman and the family was secure financially, David’s childhood was not ideal. His mother suffered from mental instability, which rendered her largely incapable of taking care of her children. His father’s focus on the social and more practical aspects of life led to conflict with a son who was shy, socially awkward, and more interested in science fiction. In spite of David’s early interest Samuel discouraged a scientific career as impractical.
During his high school years David began to take an interest in the more political and societal aspects of the world around him. Growing up in a mining town during the Great Depression, he witnessed the socially disruptive effects of economic instability. Furthermore, as a Jew with many relatives still living in Central and Eastern Europe, he became increasingly concerned with the rise of European fascism. These events were influential in the shaping of Bohm’s left-wing politics, which later played an important role in his professional career.
It was also in high school that he began to display an aptitude for solving math and science problems in a creative way. This emphasis on creativity and alternative ways to approach physics remained characteristic of Bohm’s work throughout his life. In spite of his father’s misgivings, his interest in science continued, and Samuel eventually agreed to pay his son’s way through college. In the spring of 1939 Bohm received his degree in physics from Pennsylvania State College and entered graduate school at the California Institute of Technology (CalTech) that fall. He began the trip to California on the same day war was declared in Europe.
California and Political Activity. Bohm quickly soured on CalTech. Whereas he had envisioned his time as being filled with discussing physics with other students and professors and with his own research, he found extensive coursework, competitive colleagues, and frequent examinations that required little more than the ability to perform calculations. By the beginning of his second year he resolved to transfer. In the fall of 1940 Bohm contacted J. Robert Oppenheimer, the most distinguished American theoretical physicist of the time, who helped him transfer to the University of California–Berkeley in the spring of 1941.
At Berkeley Bohm found a more favorable environment. In Oppenheimer, a man whose intellectual interests went far beyond physics, he found an advisor with whom he approached physics as more than a series of calculations. In his fellow graduate students he found colleagues with whom he could discuss physics, philosophy, politics, and music. Increasingly, the topic of conversation turned to the war and the fate of European Jewry, as Bohm’s closest friends were themselves the children of recent Jewish immigrants from East and Central Europe. This interest in politics was initially reinforced by Oppenheimer, whom Bohm—although less than some of his fellow students—saw more as a mentor than as simply a physics advisor.
Against the increasingly tumultuous backdrop of world affairs, Bohm continued his work in physics and established himself as one of, if not the, most promising of Oppenheimer’s students. At his advisor’s suggestion, he began research on the phenomenon of proton-deuteron collisions, a deuteron being a proton-neutron packet. Whereas his research was known at the time to address issues in elementary particle physics and stellar fusion, it later proved relevant in the far more earthly realm of hydrogen weapons. In the course of his graduate career two other concerns emerged that largely shaped his physics and philosophy. First, Bohm began to sense an almost mystical interconnectedness of objects. Beginning two decades later, he began to explore this feeling more directly and in so doing attracted a number of admirers unaware of his technical work in plasma and quantum physics. Second, he developed doubts about the Copenhagen interpretation of quantum mechanics. This approach to atomic phenomena was the standard view by the early 1940s, but Bohm found its probabilistic and acausal account of atomic physics troubling. An attempt to develop an alternative was the dominant theme of his technical work from 1951 until his death more than four decades later.
As Bohm’s scientific work progressed, so did his politics. Although his initial activity consisted primarily of attending talks by various speakers associated with left-wing causes, this involvement changed dramatically with the advent of the Manhattan Project in 1942 and the naming of Oppenheimer as its scientific director that autumn. It was at the same time that Bohm made the decision to join the Communist Party. Although he remained a member for only approximately nine months, this decision would later have far-reaching consequences. While completing his dissertation in early 1943 Bohm joined Berkeley’s Radiation Laboratory, Rad Lab, directed by Nobel Laureate Ernest Lawrence, to work on the separation of uranium isotopes as part of the Manhattan Project. During his time there he, along with other graduate students, sought to form a union at the Rad Lab. Although the union did come into existence, it was soon disbanded under intense pressure from the army and the White House. Such activity only heightened the concern of security officials in the FBI and military intelligence as to Bohm’s suitability on the project. By spring 1943 Bohm’s status as a security risk began to affect his life. When he completed his dissertation that semester, his scattering calculations were recognized as having weapons applications and immediately classified. Lacking the necessary clearance, he was denied access to his own work and thus unable to defend his dissertation. He received his doctorate only after Oppenheimer assured the Berkeley physics department that Bohm’s work was worthy of the degree. In spite of his security issues, he continued to work on the Manhattan Project throughout 1943. After leaving the project he remained at Berkeley through 1946 as a post-doc.
Princeton, Quantum Physics, and HUAC. Bohm’s status as one of the most promising young theorists in America was cemented in June 1947 when he attended the prestigious Shelter Island Conference. Invited physicists included Albert Einstein, J. Robert Oppenheimer, Hans Bethe, and numerous Nobel Laureates. The following autumn he began his new position on the faculty of Princeton University and published a number of articles on plasma physics. Over the next three and a half years, Bohm’s focus increasingly shifted from plasma physics and toward quantum mechanics, culminating in the publication of a well-received textbook, Quantum Theory, in spring 1951. Whereas the textbook focused on the orthodox view known as the Copenhagen Interpretation, which suggests that atomic phenomena are acausal and probabilistic, it was different from other texts in that it explored not only the technical aspects that could be addressed in equations but also the theory’s more philosophical and conceptual aspects.
Concurrent with Bohm’s changing interests in physics was a change in status at Princeton. Although departmental evaluations suggested that he was succeeding both as a researcher and as a teacher, the growing sentiment of anti-communism began to affect his career. Bohm’s political activity while at the Rad Lab led to his being called before the House Committee on Un-American Activities in May and June 1949. Asserting his Fifth Amendment rights, he refused to answer questions about his political past as well as those of his friends. Although the university initially supported him, its president, Harold Dodds, was among the most outspoken supporters of anti-communism in higher education, and having a former communist on the faculty was noxious to numerous alumni.
On 4 December 1950 Bohm was indicted on the charge of contempt of Congress and arrested. Princeton immediately suspended him and barred him from using any university facilities, including the library, effectively ending his tenure at Princeton. In May 1951 Bohm was acquitted of the contempt charge, and he was reinstated at Princeton in the first week of June. Bohm’s contract however was not renewed, and he left the university permanently when it expired on 30 June 1951.
Hidden Variables. It was also in June 1951 that Bohm submitted a pair of articles published on 15 January 1952 in the leading physics journal in the United States if not the world, Physical Review, titled, “A Suggested Interpretation of the Quantum Theory in Terms of ‘Hidden’ Variables.” In these articles Bohm argued that the standard view, although consistent, simply assumes that the most complete explanation of a system involves probabilities and that this assumption cannot be tested experimentally. For him, the only way to investigate the truth of this assumption was by trying to find some other interpretation of the quantum theory in terms of hidden variables, which in principle determine the precise behavior of an individual system, but which are in practice averaged over in the measurements that could be carried out at the time. In supporting his claim that physicists ought to consider this alternative, Bohm demonstrated that his interpretation led to precisely the same results for all physical processes as did the usual one. He believed the benefit of the hidden variables interpretation was that it provided a broader conceptual framework than the usual interpretation, in that it made possible a precise and continuous description of all processes even at the quantum level. This broader framework allowed for more general mathematical formulations of the theory than those allowed by the usual interpretation. In putting forth this argument, Bohm suggested that the mere possibility of such an interpretation proved that it was not necessary to give up a precise, rational, and objective description of individual systems at a quantum level of accuracy.
The initial response to Bohm’s work from physicists was silence. Worse than disagreeing with his work, many scientists, including key figures such as Niels Bohr, Werner Heisenberg, and Wolfgang Pauli, did not feel that Bohm’s challenge merited a response. For most working physicists at the time, his alternative did not seem worth considering because it did not yield new results, but simply offered a different explanation than the standard view. Because physicists were already familiar with the Copenhagen approach, they found little or nothing to be gained from adopting the hidden variables interpretation. With respect to the issues that Bohm sought to raise, most in the physics community saw the subject as closed.
The supremacy of the Copenhagen Interpretation had been firmly established by the late 1920s, and had been highlighted at the 1927 Solvay Congress by Pauli’s challenge of Louis de Broglie’s interpretation of atomic motion in terms of particles being guided by pilot-waves. As a result of Pauli’s attack, de Broglie himself abandoned his pilot-wave approach. It was not until Bohm’s work that another scientist picked up de Broglie’s line of thought, and, as a result, this work is sometimes subsumed under the title of “de Broglie-Bohm theory of motion.”
The esteemed mathematician John von Neumann moved the physics community further away from a hidden-variables approach when in 1932 he published what was seen as a mathematical proof for the non-existence of hidden variables. In spite of the work of Pauli and von Neumann in critiquing non-Copenhagen approaches, some physicists, most notably Einstein, continued to question the orthodox view by arguing that it was incomplete. Einstein’s concerns resulted in a 1935 Physical Review paper entitled, “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?” which he co-authored with Boris Podolsky and Nathan Rosen—the paper became known as the EPR paper. Bohr’s successful refutation of Einstein’s challenge effectively ended the debate over the primacy of Copenhagen. Even Einstein, in spite of his reservations concerning the standard view, was critical of Bohm’s approach because it suggested the possible existence of superluminal signals, i.e. signals that could travel faster than the speed of light. For Einstein the notion that anything could travel faster than light was unacceptable.
Brazil and Israel. Although Bohm had submitted the articles while still at Princeton, by the time they were published he was teaching at the University of São Paulo (USP) in Brazil. After his contract had expired at Princeton, he was unable to obtain another position in the United States due to the political climate of the time. With the help of two Brazilian physics graduate students who were at Princeton prior to his departure, Bohm began working at USP in autumn 1951 and thus was able to maintain a physics career in spite of the dislocation. Leaving the country, however, did not put an end to Bohm’s political problems. In late October 1951 Bohm was called to the U.S. Consulate in São Paulo, at which time his passport was seized and was returned to him marked as being good only for return to the United States. Afraid to return to the United States because of the chance of being arrested and unable to travel elsewhere, Bohm remained in Brazil until January 1955 when he moved to Israel and began teaching at the Technion in Haifa. His movement to Israel was made possible with the help of Einstein and only after Bohm took the drastic step in 1954 of giving up his U.S. passport and obtaining a Brazilian one.
Although not near the level of Princeton, the Technion did offer better resources for Bohm’s research than did Brazil. It also offered greater interaction with other physicists from the United States and Europe, including David Fox, whom Bohm first met as a fellow graduate student at Berkeley, and Nathan Rosen, one of the coauthors of the EPR paper. On a personal level the move to Israel was significant in that it was there that Bohm met Saral Woolfson, a young Englishwoman living in Israel. The two married on 14 March 1956 in Haifa and remained married until his death in 1992. The Bohms had no children.
Bristol and Birkbeck. While the Technion offered more scientific interaction with others, Bohm still felt the need for increased stimulation and so in late summer 1957 he and his wife left Israel for England, where he had accepted a position as a research associate at Bristol University. Although he found Bristol far from ideal, his time there did yield his best received work in quantum mechanics— the 1959 discovery of the Aharonov-Bohm effect, which he co-discovered with the graduate student Yakir Aharonov. The effect, which resulted in Bohm’s receiving numerous awards, contradicted the belief, dating back to the nineteenth-century work of James Clerk Maxwell on electricity and magnetism, that a vector potential was simply a mathematical convenience. Bohm and Aharonov demonstrated that on the quantum level, vector potentials, like electric and magnetic fields, had a physical effect. The discovery arose when Aharonov first noticed that even when electrons did not pass through a magnetic field, their interference properties could be changed simply by the field. Unlike the hidden variables interpretation, the Aharonov-Bohm effect became a standard topic in advanced quantum mechanics courses.
In 1961 Bohm was offered and accepted the chair for theoretical physics at Birkbeck College in London. Although the historically working-class school had limited resources, Bohm saw the move as one step closer to obtaining a position at a more prestigious university. Birk-beck, however, proved to be his final position, as he remained there until his retirement in 1983. Throughout his time in London Bohm collaborated extensively with Basil Hiley.
Philosophy/Physics in London. In spite of its poor reception in the 1950s, by the 1990s Bohm’s hidden variables approach enjoyed a renaissance as numerous philosophers of science began to reexamine the question of whether or not his approach did help resolve problems involving quantum measurement. Although working physicists did not make use of Bohm’s work at the end of the twentieth century, it became the subject of many books and articles more than forty years after it first appeared in print.
During his early years in London, however, the causal interpretation played only a minor role in the work he pursued. At Birkbeck, while much of Bohm’s work remained technical, his interest in the philosophical aspects of science began to play a more prominent role than ever. He focused not simply on finding new equations of motion, but on reexamining the basic categories that were used. For example, Bohm and Hiley explored existing notions of order, space and time, causality and
chance—a topic he first explored at length in his 1957 work Causality and Chance in Modern Physics—and other related topics. Rather than simply exploring particle and fields as they interacted, Bohm focused increasingly on notions of process. Seeking to move away from viewing these concepts as a mere matter of making measurements, Bohm emphasized topology and how phenomena such as small-scale fluctuations expected in quantum gravity could result in a drastic alteration of traditional notions of the structure of spacetime. This reexamination of categories led Bohm to incorporate numerous other fields such as philosophy, biology, linguistics, and art and culminated in the 1987 work Science, Order, and Creativity, which he co-authored with David Peat.
During the first decade at Birkbeck, Bohm, like Niels Bohr before him, became increasingly interested in the role of communication and language. It was also during this period that Bohm thought extensively about questions of order and its deeply entwined constitutive and descriptive aspects, especially as they applied to quantum processes. In 1971 Bohm proposed the notion of implicate and explicate order. In doing so he suggested that it is not possible to display all aspects of a quantum process together at one time. In that one can have only a partial view at any given time, some aspects must remain implicit in any single display. Displaying a view explicates one aspect of the process at the expense of a complementary aspect that cannot be displayed at the same time. The implicit aspect can be explicated only by changing the display, making some of the original aspects implicit. Although initially treating questions of quantum process, the goal of implicate and explicate order was to provide a more coherent framework for exploring the question of wholeness and the relationship between objects.
Wholeness and Nonlocality. This notion of wholeness led Bohm to revisit questions of non-separability and nonlocality in nature, which had first emerged with his hidden variables interpretation and posited the possibility of superluminal signals. Since 1964 the question of nonlocality had been the subject of significant interest in the physics community due to the work of John S. Bell and his famous inequalities. Using simple math Bell was able to show that the notion of locality (i.e., that physical effects propagate at a finite speed) was inconsistent with quantum mechanics’ description of nature. For Bell, the EPR critique assumed local realism and such an assumption led to certain requirements, mathematically resulting in inequalities which had to be satisfied. These inequalities were violated by quantum mechanical predictions; neither Bohm’s theory nor Copenhagen satisfied them. Although Bell’s work undermined the viability of Bohm’s hidden variables approach as well, by the mid-1970s the causal approach, though different from its 1950s form and shaped in part by his work on explicate and implicate order, was once again at the center of Bohm’s thoughts. The late 1970s and early 1980s produced several attempts at physically investigating Bell’s inequalities, culminating in the work published by French physicist Alain Aspect in 1981 and 1982, which showed experimentally that Bell’s inequalities were, indeed, violated.
The final development in Bohm’s work was the development of the quantum potential. Whereas many scientists had criticized Bohm’s 1952 papers as a return to mechanistic and causal principles that had dominated classical physics prior to the quantum revolution, a similar charge could not be leveled against the quantum potential. According to Bohm the quantum potential guided the electron in a nonmechanical way with its influence being a result of its form and not its strength. It was a concept that had no antecedent in physics.
Beyond his technical work in physics, Bohm was known to many of his admirers solely through his work on questions of interconnectedness/wholeness and the nature of thought, all of which were explored during his time with the Indian philosopher and teacher Jiddu Krishna-murti, with whom he maintained a close friendship from 1961 to 1984. For many, Bohm was not simply a great physicist but a great thinker on important esoteric subjects. On 27 October 1992, Bohm died of a heart attack on the steps of his home in suburban London.
Bohm's Papers, 1953–1996, are held at the University of London, Birkbeck College Library.
WORKS BY BOHM
Quantum Theory. New York: Prentice-Hall, 1951.
“A Suggested Interpretation of the Quantum Theory in Terms of Hidden Variables. I.” Physical Review 85 (1952): 166–179.
“A Suggested Interpretation of the Quantum Theory in Terms of Hidden Variables. II” Physical Review 85 (1952): 180–193.
Causality and Chance in Modern Physics. Foreword by Louis De Broglie. London, Routledge and Paul, 1957.
With Yakir Aharonov. “Significance of Electromagnetic Potentials in the Quantum Theory.” Physical Review Series II(1959): 485–491.
The Special Theory of Relativity. New York: W. A. Benjamin, 1965.
Wholeness and the Implicate Order. Boston: Routledge & Kegan Paul, 1981.
With David Peat. Science, Order, and Creativity. New York: Bantam Books, 1987.
On Dialogue. Edited by Lee Nichol. New York: Routledge, 1996.
On Creativity. Edited by Lee Nichol. New York: Routledge, 1998.
Cushing, James T. Quantum Mechanics: Historical Contingency and the Copenhagen Hegemony. Chicago: University of Chicago Press, 1994.
———. Arthur Fine, and Sheldon Goldstein, eds. Bohmian Mechanics and Quantum Theory: An Appraisal. Dordrecht, Holland: Kluwer, 1996.
Freire, Olival, Jr. “Science and Exile: David Bohm, the Cold War, and a New Interpretation of Quantum Mechanics.” Historical Studies in the Physical and Biological Sciences 36:1 (2005): 1–34.
Holland, Peter. R. The Quantum Theory of Motion: An Account of the de Broglie-Bohm Causal Interpretation of Quantum Mechanics. Cambridge, MA: Cambridge University Press, 1993.
Kojevnikov, Alexei. “David Bohm and the Collective Movement.” Historical Studies in the Physical and Biological Sciences 33:1 (2002): 161–192.
Olwell, Russell. “Physical Isolation and Marginalization in Physics: David Bohm’s Cold War Exile.” Isis 90 (December 1999): 738–756.
Peat, F. David. Infinite Potential: The Life and Times of David Bohm. Reading, MA: Addison-Wesley, 1997.