3,723 research outputs found
Chaos and quantum-nondemolition measurements
The problem of chaotic behavior in quantum mechanics is investigated against the background of the theory of quantum-nondemolition (QND) measurements. The analysis is based on two relevant features: The outcomes of a sequence of QND measurements are unambiguously predictable, and these measurements actually can be performed on one single system without perturbing its time evolution. Consequently, QND measurements represent an appropriate framework to analyze the conditions for the occurrence of ‘‘deterministic randomness’’ in quantum systems. The general arguments are illustrated by a discussion of a quantum system with a time evolution that possesses nonvanishing algorithmic complexity
Randomness? What randomness?
This is a review of the issue of randomness in quantum mechanics, with special emphasis on its ambiguity; for example, randomness has different antipodal relationships to determinism, computability, and compressibility. Following a (Wittgensteinian) philosophical discussion of randomness in general, I argue that deterministic interpretations of quantum mechanics (like Bohmian mechanics or 't Hooft's Cellular Automaton interpretation) are strictly speaking incompatible with the Born rule. I also stress the role of outliers, i.e. measurement outcomes that are not 1-random. Although these occur with low (or even zero) probability, their very existence implies that the no-signaling principle used in proofs of randomness of outcomes of quantum-mechanical measurements (and of the safety of quantum cryptography) should be reinterpreted statistically, like the second law of thermodynamics. In three appendices I discuss the Born rule and its status in both single and repeated experiments, review the notion of 1-randomness (or algorithmic randomness) that in various guises was investigated by Solomonoff, Kolmogorov, Chaitin, Martin-Lo"f, Schnorr, and others, and treat Bell's (1964) Theorem and the Free Will Theorem with their implications for randomness
Quantum randomness and value indefiniteness
As computability implies value definiteness, certain sequences of quantum
outcomes cannot be computable.Comment: 13 pages, revise
Quantum Algorithmic Integrability: The Metaphor of Polygonal Billiards
An elementary application of Algorithmic Complexity Theory to the polygonal
approximations of curved billiards-integrable and chaotic-unveils the
equivalence of this problem to the procedure of quantization of classical
systems: the scaling relations for the average complexity of symbolic
trajectories are formally the same as those governing the semi-classical limit
of quantum systems. Two cases-the circle, and the stadium-are examined in
detail, and are presented as paradigms.Comment: 11 pages, 5 figure
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