Hugh Everett III (1930–1982)
American physicist who proposed the relative state interpretation of quantum mechanics, which became the basis of the many-worlds-interpretation (MWI). His theory dropped the wave function collapse postulate of quantum measurement theory, incorporating the observer into the same quantum state as the observation result. The quantum statistic becomes a measure of the branching of the universal wave function.
The Doctoral Thesis
Everett’s Princeton PhD thesis, The Theory of the Universal Wave Function (1956–57), was developed under John Archibald Wheeler. A shorter version was published in 1957 as “Relative State Formulation of Quantum Mechanics” — Wheeler contributed the title “relative state”; Everett originally called his approach the “Correlation Interpretation,” where “correlation” refers to quantum entanglement. The thesis argues that the observer is a physical system entangled with the measured system, so the “collapse” of the wave function is merely the appearance of one branch from within.
Career and Reception
The theory was largely ignored after publication. Everett left academia in 1957 to work in the defense industry, founding small companies specializing in U.S. government contracts. His meeting with Bohr in Copenhagen (1959) was “doomed from the beginning”; Bohr’s collaborator Rosenfeld said Bohr “could have no patience with him.” Wheeler disavowed the theory in 1980. The work gained credibility with the discovery of quantum decoherence in the 1970s, and MWI has become one of the important interpretations of quantum mechanics.
Belief and Legacy
People who knew Everett reported that he believed in the literal reality of the other quantum worlds; his son (musician Mark Oliver Everett of the band Eels) and wife reported he “never wavered in his belief.” Bryce DeWitt popularized the theory in the 1970s, naming it “many-worlds” and editing The Many-Worlds Interpretation of Quantum Mechanics (1973). Died 19 July 1982.
References
- Wikipedia (2026). Hugh Everett III. 1