A categorical framework for quantum theory (original) (raw)
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The Relativity Principle at the Foundation of Quantum Mechanics
arXiv (Cornell University), 2021
Quantum information theorists have created axiomatic reconstructions of quantum mechanics (QM) that are very successful at identifying precisely what distinguishes quantum probability theory from classical and more general probability theories in terms of information-theoretic principles. Herein, we show how one such principle, Information Invariance & Continuity, at the foundation of those axiomatic reconstructions maps to "no preferred reference frame" (NPRF, aka "the relativity principle") as it pertains to the invariant measurement of Planck's constant h for Stern-Gerlach (SG) spin measurements. This is in exact analogy to the relativity principle as it pertains to the invariant measurement of the speed of light c at the foundation of special relativity (SR). Essentially, quantum information theorists have extended Einstein's use of NPRF from the boost invariance of measurements of c to include the SO(3) invariance of measurements of h between different reference frames of mutually complementary spin measurements via the principle of Information Invariance & Continuity. Consequently, the "mystery" of the Bell states that is responsible for the Tsirelson bound and the exclusion of the no-signalling, "superquantum" Popescu-Rohrlich joint probabilities is understood to result from conservation per Information Invariance & Continuity between different reference frames of mutually complementary qubit measurements, and this maps to conservation per NPRF in spacetime. If one falsely conflates the relativity principle with the classical theory of SR, then it may seem impossible that the relativity principle resides at the foundation of non-relativisitic QM. In fact, there is nothing inherently classical or quantum about NPRF. Thus, the axiomatic reconstructions of QM have succeeded in producing a principle account of QM that reveals as much about Nature as the postulates of SR.
The Quantum Mechanical Frame of Reference - Part 2: The Third Logical Type
In Part 1 the properties of QBism are shown to be natural consequences of taking quantum mechanics at face value, as does Everett in his Relative State Formulation (1957). In Part 2 supporting evidence is presented. Parmenides' (Palmer, 2012) notion that the physical world is static and unchanging is vividly confirmed in the new physics. This means the time evolution of the physical world perceived by observers only occurs at the level of appearances as noted by Davies (2002). In order to generate this appearance of time evolution, a moving frame of reference is required: this is the only possible explanation of the enactment of the dynamics of physics in a static universe. Such a frame of reference can only be a fundamental property of the unitary system as a whole, of different logical type to the quantum state. Thus an ontological category in addition to physical existence is required to complete the science. At this level of logical type, all multiply instantiated copies of an inside view constitute a single entity. Thus the superposition proposed in Part 1 is inevitably effected; and the nature of physical reality on the inside view is as described in QBism.
On the foundations of quantum physics
Physics Essays, 2012
Some aspects of the interpretation of quantum theory are discussed. It is emphasized that quantum theory is formulated in a Cartesian coordinate system; in other coordinates the result obtained with the help of the Hamiltonian formalism and commutator relations between 'canonically conjugated' coordinate and momentum operators leads to a wrong version of quantum mechanics. In this connection the Feynman integral formalism is also discussed. In this formalism the measure is not well-defined and there is no idea how to distinguish between the true version of quantum mechanics and an incorrect one; it is rather a mnemonic rule to generate perturbation series from an undefined zero order term. The origin of time is analyzed in detail by the example of atomic collisions. It is shown that the time-dependent Schrödinger equation for the closed three-body (two nuclei + electron) system has no physical meaning since in the high impact energy limit it transforms into an equation with two independent time-like variables; the time appears in the stationary Schrödinger equation as a result of extraction of a classical subsystem (two nuclei) from a closed three-body system. Following the Einstein-Rosen-Podolsky experiment and Bell's inequality the wave function is interpreted as an actual field of information in the elementary form. The relation between physics and mathematics is also discussed.
An alternative foundation of quantum theory
arXiv (Cornell University), 2023
A new approach to quantum theory is proposed in this paper. The basis is taken to be theoretical variables, variables that may be accessible or inaccessible, i.e., it may be possible or impossible for an observer to assign arbitrarily sharp numerical values to them. In an epistemic process, the accessible variables are just ideal observations connected to an observer or to some communicating observers. Group actions are defined on these variables, and group representation theory is the basis for developing the Hilbert space formalism here. Operators corresponding to accessible theoretical variables are derived, and in the discrete case, it is proved that the possible physical values are the eigenvalues of these operators. The focus of the paper is some mathematical theorems paving the ground for the proposed foundation of quantum theory. It is indicated here that the groups and transformations needed in this approach can be constructed explicitly in the case where the accessible variables are finite-dimensional. In case, this simplifies the theory considerably: To reproduce the Hilbert space formulation, it is enough to assume the existence of two complementary variables. The essential use of inaccessible variables can be avoided by basing the approach on some simple category theory.The interpretation inferred from the proposed foundation here may be called a general epistemic interpretation of quantum theory. A special case of this interpretation is QBism; it also has a relationship to several other interpretations.
Statement of the principles of quantum mechanics in the course of general physics
Russian Physics Journal, 2011
Interpretation of quantum physics and its principles is a problem that has yet to be solved to the end in spite of the fact that quantum physics formulated more than 80 years ago successfully explains the microcosm phenomena. Today there are several competing interpretations, including the Copenhagen interpretation in different forms, the Everett many-worlds interpretation, the Gell-Mann and Hartle many-histories interpretation, and the nonlocal hidden variables theory. From the above-listed interpretations, the most advanced quantum theory that does not require changes of the mathematical apparatus is the Copenhagen interpretation. All other interpretations (with possible exception of the many-worlds interpretation) call for changes in the quantum theory formalism.
American Journal of Physics, 1979
We reformulate the problem of the "interpretation of quantum mechanics" as the problem of DERIVING the quantum mechanical formalism from a set of simple physical postulates. We suggest that the common unease with taking quantum mechanics as a fundamental description of nature could derive from the use of an incorrect notion, as the unease with the Lorentz transformations before Einstein derived from the notion of observer independent time. Following an an analysis of the measurement process as seen by different observers, we propose a reformulation of quantum mechanics in terms of INFORMATION THEORY. We propose three different postulates out of which the formalism of the theory can be reconstructed; these are based on the notion of information about each other that systems contain. All systems are assumed to be equivalent: no observer-observed distinction, and information is interpreted as correlation. We then suggest that the incorrect notion that generates the unease with quantum mechanichs is the notion of OBSERVER INDEPENDENT state of a system.
Quantum Mechanics as a Principle Theory
Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics, 2000
I show how quantum mechanics, like the theory of relativity, can be understood as a 'principle theory' in Einstein's sense, and I use this notion to explore the approach to the problem of interpretation developed in my book Interpreting the Quantum World.
M ay 2 01 8 From Quantum Axiomatics to Quantum Conceptuality ∗
2018
Since its inception, many physicists have seen in quantum mechanics the possibility, if not the necessity, of bringing cognitive aspects into the play, which were instead absent, or unnoticed, in the previous classical theories. In this article, we outline the path that led us to support the hypothesis that our physical reality is fundamentally conceptual-like and cognitivisticlike. However, contrary to the ‘abstract ego hypothesis’ introduced by John von Neumann and further explored, in more recent times, by Henry Stapp, our approach does not rely on the measurement problem as expressing a possible ‘gap in physical causation’, which would point to a reality lying beyond the mind-matter distinction. On the contrary, in our approach the measurement problem is considered to be essentially solved, at least for what concerns the origin of quantum probabilities, which we have reasons to believe they would be epistemic. Our conclusion that conceptuality and cognition would be an integral ...