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Annalen der Physik

Cover Picture: Objective Realism and Joint Measurability in Quantum Many Copies (Ann. Phys. 7/2018)

Adam Bednorz

Published Jul 1, 2018• 0 citations
Publisher

Abstract

Quantum Many Copies In quantum theory, Schrödinger's cat exists only when one looks – there is no objective realism. The problem can be resolved assuming many copies of the cat. The cat-copies undergo the same dynamics and do not interact. When observed, the copies collapse to the same state, dead or alive, although with a finite probability. In article 1800002, Adam Bednorz discusses quantum objective realism for incompatible observables consistent with experiments, which can be defined assuming the existence of weakly interacting many copies of the same system.

DOI
10.1002/andp.201870034

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Objective Realism and Joint Measurability in Quantum Many Copies

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Abstract In the standard quantum theory, one can measure precisely only a subset of the incompatible observables. It results in lack of a formal joint probability defining objective realism even if we accept nonlocal or certain faster‐than‐light interactions. Here, a construction of such realism extending the usual single‐copy description to many copies, partially analogous to familiar many worlds, is proposed. Failure of the standard single copy can be easily looked for experimentally. The copies should interact weakly at the macroscopic level, leading to effective collapse to a single identical pointer state. Experimental evidence for this conjecture could be obtained by detecting incomplete collapse in sequential measurements or finding deviations from the single‐copy Born rule when observing simple quantum systems.

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Quantum Many Copies In quantum theory, Schrödinger's cat exists only when one looks – there is no objective realism. The problem can be resolved assuming many copies of the cat. The cat-copies undergo the same dynamics and do not interact. When observed, the copies collapse to the same state, dead or alive, although with a finite probability. In article 1800002, Adam Bednorz discusses quantum objective realism for incompatible observables consistent with experiments, which can be defined assuming the existence of weakly interacting many copies of the same system.
Abstract In the standard quantum theory, one can measure precisely only a subset of the incompatible observables. It results in lack of a formal joint probability defining objective realism even if we accept nonlocal or certain faster‐than‐light interactions. Here, a construction of such realism extending the usual single‐copy description to many copies, partially analogous to familiar many worlds, is proposed. Failure of the standard single copy can be easily looked for experimentally. The copies should interact weakly at the macroscopic level, leading to effective collapse to a single identical pointer state. Experimental evidence for this conjecture could be obtained by detecting incomplete collapse in sequential measurements or finding deviations from the single‐copy Born rule when observing simple quantum systems.
Schrödinger's cat paradox has persisted for nearly a century as a demonstration of the apparent absurdity of quantum superposition when extended to macroscopic scales. This technical note demonstrates that the paradox dissolves entirely within the CAT'S Theory framework through the triadic invariant Reality = Pattern × Intent × Presence (P × I × Pr). We argue that the cat is neither "both alive and dead" nor the victim of mysterious collapse. Instead, superposition represents a state where Presence (Pr) has not yet instantiated, yielding P × I × 0 = 0 (potential but not actual). Measurement does not "cause" collapse through mysterious observer effects; it provides the Presence component required for actualization. This resolution eliminates the need for Multiple Worlds or hidden variables while maintaining consistency with quantum mechanical predictions.
This paper reviews and suggests a resolution of the problem of definite outcomes of measurement. This problem, also known as ‘Schrodinger’s cat’, has long posed an apparent paradox because the state resulting from a measurement appears to be a quantum superposition in which the detector is in two macroscopically distinct states (alive and dead in the case of the cat) simultaneously. Many alternative interpretations of the quantum mathematical formalism, and several alternative modifications of the theory, have been proposed to resolve this problem, but no consensus has formed supporting any one of them. Applying standard quantum theory to the measurement state, together with the analysis and results of decades of nonlocality experiments with pairs of entangled systems, this paper shows the entangled measurement state is not a paradoxical macroscopic superposition of states. It is instead a phase-dependent superposition of correlations between states of the subsystems. Thus Schrodinger’s cat is a non-paradoxical ‘macroscopic correlation’ in which one of the two correlated systems happens to be a detector. This insight resolves the problem of definite outcomes but it does not entirely resolve the measurement problem because the entangled state is still reversible.
Abstract Complementarity tells us we cannot know precisely the values of all the properties of a quantum object at the same time: the precise determination of one property implies that the value of some other (complementary) property is undefined. E.g. the precise knowledge of the position of a particle implies that its momentum is undefined. Here we show that a Schrödinger cat has a well defined value of a property that is complementary to its “being dead or alive” property. Then, thanks to complementarity, it has an undefined value of the property “being dead or alive”. In other words, the cat paradox is explained through quantum complementarity: of its many complementary properties, any quantum system, such as a cat, can have a well defined value only of one at a time. Schrödinger’s cat has a definite value of a property which is complementary to “being dead or alive”, so it is neither dead nor alive. Figuratively one can say it is both dead and alive. While this interpretation only uses textbook concepts (the Copenhagen interpretation), apparently it has never explicitly appeared in the literature. We detail how to build an Arduino based simulation of Schrödinger’s experiment based on these concepts for science outreach events.
Abstract In the Schrödinger cat gedanken experiment a “cat” is in a quantum superposition of two macroscopically distinct states. There is the apparent interpretation that the “cat” is not in one state or the other, “alive” or “dead”. Here this interpretation is proved objectively. I propose the following definition of macroscopic reality: first, that the “cat” is either dead or alive, the measurement revealing which; second, that measurements on other “cats” some distance away cannot induce the macroscopic change, “dead” to “alive” and vice versa, to the “cat”. The predictions of quantum mechanics are shown to be incompatible with this premise.
Schrodinger's cat is traditionally presented as a paradox highlighting the tension between quantum superposition and classical observation. Standard interpretations invoke either a fundamental wavefunction collapse, ontological branching of universes, or subjective Bayesian updating. In this paper, we propose a reinterpretation grounded in the Informational Observer Framework, according to which the paradox does not originate from an ontological superposition of macroscopic states, but from an unresolved informational configuration at the observer level. The cat itself is never simultaneously alive and dead; rather, the observer remains in a state of informational compression prior to interaction. Within this framework, wavefunction collapse is reinterpreted as an observer-level informational phase transition, not as a fundamental physical discontinuity. This approach preserves macroscopic realism, avoids ontological inflation, and reframes the measurement problem as an emergent informational phenomenon.