These troubling features, called “the measurement problem,” were hotly debated in the 1920s. But overwhelming any objections was the fact that the Copenhagen interpretation works! Its results agree precisely with experiments, the final test of any theory, and inspire real devices. Even so, David Joseph Bohm (1917–1992) and Hugh Everett III (1930–1982) sought equally valid theories without any incongruities. In the 1950s, these two American physicists dared to challenge the conventional Copenhagen interpretation with their “pilot wave” and “many-worlds” theories, respectively. Though from different backgrounds, Bohm and Everett shared characteristics that helped them seek answers: mathematical aptitude, necessary to manipulate quantum theory; and unconventional career paths, which separated them from the orthodoxy of academic physics.
Bohm was a second-generation American, born into an immigrant family from Europe that operated a furniture store in Wilkes-Barre, Pennsylvania. In high school, where his physics instructor described him as “outstanding” and “brilliant,” Bohm developed his own alternative ideas about Bohr’s hydrogen atom. After undergraduate work at Penn State, he began earning a PhD in nuclear physics in 1941 under J. Robert Oppenheimer (1904–1967) at the University of California, Berkeley. The United States was engaged in World War II at the time and was about to build an atomic bomb. Bohm’s doctoral research was classified, and he was awarded his degree in 1943 without writing a dissertation. Though Oppenheimer wanted Bohm to work with him at Los Alamos, Bohm couldn’t get security clearance as he had briefly been, in the early 1940s, a member of the Communist Party.
In 1947, supported by theorist John Wheeler, Bohm became an assistant professor at Princeton. There he taught quantum mechanics and wrote Quantum Theory (1951), in which he presented the Copenhagen interpretation, only to disavow it the next year, when he published his alternative theory in a pair of papers in the Physical Review (in 1957, he expounded his ideas further in his book Causality and Chance in Modern Physics).
But in 1951, his life had taken a serious turn. In that Cold War era of McCarthyism, Bohm was brought before the House Committee on Un-American Activities (HUAC). He pleaded the Fifth Amendment against self-incrimination, and he was first indicted and jailed for contempt of Congress and then acquitted when the Supreme Court decriminalized this action. Still, the damage was done. Princeton didn’t renew Bohm’s contract and banned him from campus in June 1951. Unable to obtain a new academic position in the US, he began a life-long exile, taking temporary teaching positions in Brazil and elsewhere. Finally, in 1961, he accepted the offer of a chaired professorship in physics at Birkbeck College, London. He remained in that position until he retired in 1983, continuing to develop his new approach, the “pilot wave” theory.