QBism, the Perimeter of Quantum Bayesianism

By Christopher A. Fuchs. 2010

335 citations recorded by the source corpus.

This article summarizes the Quantum Bayesian point of view of quantum mechanics, with special emphasis on the view's outer edges---dubbed QBism. QBism has its roots in personalist Bayesian probability theory, is crucially dependent upon the tools of quantum information theory, and most recently, has set out to investigate whether the physical world might be of a type sketched by some false-started philosophies of 100 years ago (pragmatism, pluralism, nonreductionism, and meliorism). Beyond conceptual issues, work at Perimeter Institute is focused on the hard technical problem of finding a good representation of quantum mechanics purely in terms of probabilities, without amplitudes or Hilbert-space operators. The best candidate representation involves a mysterious entity called a symmetric informationally complete quantum measurement. Contemplation of it gives a way of thinking of the Born Rule as an addition to the rules of probability theory, applicable when an agent considers gambling on the consequences of his interactions with a newly recognized universal capacity: dimension (formerly Hilbert-space dimension). (The word "capacity" should conjure up an image of something like gravitational mass---a body's mass measures its capacity to attract other bodies. With hindsight one can say that the founders of quantum mechanics discovered another universal capacity, "dimension.") The article ends by showing that the egocentric elements in QBism represent no impediment to pursuing quantum cosmology and outlining some directions for future work.

Subfields: Atomic and Molecular Physics, and Optics, Computational Theory and Mathematics, History and Philosophy of Science

View Paper: https://www.semanticscholar.org/paper/58e159f3fed8a1fd8d31280318bea1493268fe03

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Citations in the corpus

Measurements on the reality of the wavefunction (2014, methodology): “Not all scientists—including in particular Quantum Bayesianists[2–4]—believe that our observations of the physical world can be entirely derived from an underlying objective reality.”
Quantum Theory: A Pragmatist Approach (2010, background): “A pragmatist will surely endorse Fuchs’s ([2010]) view that quantum theory as a whole is ‘a users’ manual that any agent can pick up and use to help make wise decisions in this world of inherent uncertainty’.”
The Interface Theory of Perception (2009, positive): “That wave functions use complex amplitudes rather than probabilities is mere computational convenience; wave functions can equally well be written using standard probabilities, as is done in quantum Bayesianism (Fuchs, 2010).”
An introduction to QBism with an application to the locality of quantum mechanics (2013, background): “Although it differs in many important ways from what has come to be called “the Copenhagen interpretation”, QBism[4] - Quantum Bayesianism - agrees with Bohr that the primitive concept of experience is fundamental to an understanding of science.”
Quantum theory cannot consistently describe the use of itself (2016, background): “While this is different from (1), the difference can be explained by the agents’ distinct level of knowledge: F has observed z and hence knows the spin direction, whereas W is ignorant about it [6].”
On Participatory Realism (2016, background): “John Archibald Wheeler’s writings were a tremendous influence on the point of view on quantum mechanics we now call QBism [1], developed by the author [2, 3, 4, 5] and colleagues Carlton Caves [6, 7, 8, 9], Asher Peres [10, 11], Marcus Appleby [12, 13, 14, 18, 15, 16, 17], Blake Stacey [19, 20, 21],”
Is the Quantum State Real? An Extended Review of -ontology Theorems (2014, background): “The most fine grained description of the toy bit is always its ontic state, but we might not know exactly which of the ontic states is occupied.”