A landmark book on the influential many-worlds interpretation of quantum mechanics

In 1957, Hugh Everett proposed a novel interpretation of quantum mechanics—a view that eventually became known as the many-worlds interpretation. This book presents Everett’s two landmark papers on the idea—“‘Relative State’ Formulation of Quantum Mechanics” and “The Theory of the Universal Wave Function”—as well as further discussion of the idea in papers from a number of other physicists: J. A. Wheeler, Bryce DeWitt, L. N. Cooper and D. Van Vechten, and Neill Graham.

In his interpretation, Everett denies the existence of a separate classical realm and asserts the propriety of considering a state vector for the whole universe. Because this state vector never collapses, reality as a whole is rigorously deterministic. This reality, which is described jointly by the dynamical variables and the state vector, isn’t the reality customarily perceived; rather, it’s a reality composed of many worlds. By virtue of the temporal development of the dynamical variables, the state vector decomposes naturally into orthogonal vectors, reflecting a continual splitting of the universe into a multitude of mutually unobservable but equally real worlds, in each of which every good measurement has yielded a definite result, and in most of which the familiar statistical quantum laws hold.

Bryce S. DeWitt (1923–2004) was a prize-winning theoretical physicist and professor emeritus of physics at the University of Texas at Austin. Neill Graham (1941–2015) was a physicist and writer.

Habib Ammari is director of research at the French National Center for Scientific Research and professor of mathematics at the École Normale Superiéure. Elie Bretin is a postdoctoral researcher in mathematics at the École Polytechnique. Josselin Garnier is professor of mathematics at Université Paris VII. Hyeonbae Kang is the Jungseok Chair Professor of Mathematics at Inha University in South Korea. Hyundae Lee is assistant professor of mathematics at Inha University. Abdul Wahab is a postdoctoral researcher in mathematics at Université Paris VII.