Hugh Everett III (/ˈɛvərɪt/; November 11, 1930 – July 19, 1982) was an American physicist who, in his 1957 PhD thesis, proposed relative state interpretation of quantum mechanics.

Sincerely yours, A. Einstein[6]Everett won a half scholarship to St. John's College High School in Washington, D.C. From there, he moved to the nearby Catholic University of America to study chemical engineering as an undergraduate.

Everett received a National Science Foundation fellowship that allowed him to attend Princeton University for graduate studies.

He started his studies at Princeton in the mathematics department, where he worked on the nascent field of game theory under Albert W. Tucker, but slowly drifted into physics.

Completing his PhD within a year of starting at WSEG was a job requirement, and in April 1957 he returned briefly to Princeton to defend his thesis.

The conceptual gulf between their positions was too wide to allow any meeting of minds; Léon Rosenfeld, one of Bohr's devotees, called Everett "undescribably stupid" and said he "could not understand the simplest things in quantum mechanics".

[1] Lagrange multipliers had relevance for operations research, and Everett applied his discovery commercially as a defense analyst and a consultant.

In 1962 Everett accepted an invitation to present the relative-state formulation (as it was still called) at a conference on the foundations of quantum mechanics at Xavier University.

In his exposition Everett presented his derivation of probability and also stated explicitly that observers in all branches of the wavefunction were equally "real."

[18] In August 1964, Everett and several WSEG colleagues started Lambda Corp. to apply military modeling solutions to various civilian problems.

During the early 1970s, defense budgets were curtailed and most money went to operational duties in the Vietnam War, resulting in Lambda eventually being absorbed by the General Research Corp.

In 1973, Everett and Donald Reisler (a Lambda colleague and fellow physicist) left the firm to establish DBS Corporation in Arlington, Virginia.

Although the firm conducted defense research (including work on United States Navy ship maintenance optimization and weapons applications), it primarily specialized in "analyzing the socioeconomic effects of government affirmative action programs" as a contractor under the auspices of the Department of Justice and the Department of Health, Education and Welfare.

[19] For a while, the company was partially supported by American Management Systems, a business consulting firm that drew upon algorithms Everett developed.

Everett cultivated an early aptitude for computer programming at IDA and favored the TRS-80 at DBS, where he primarily worked for the rest of his life.

In 1970 Bryce DeWitt wrote an article for Physics Today on Everett's relative-state theory, which he dubbed many-worlds, which prompted a number of letters from physicists.

[18] Everett, who "never wavered in his belief in his many-worlds theory",[20] enjoyed the presentation; it was the first time in years he had talked about his quantum work in public.

[18]: 24  Wheeler started the process of returning Everett to a physics career by establishing a new research institute in California, but nothing came of that proposal.

[23] It is managed by co-founder Elaine Tsiang, who received a PhD in physics under Bryce DeWitt at the University of North Carolina at Chapel Hill before working for DBS as a programmer.