scholarly journals Decoherence and its role in the modern measurement problem

2012 ◽  
Vol 370 (1975) ◽  
pp. 4576-4593 ◽  
Author(s):  
David Wallace
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum Measurement ◽  
Measurement Problem ◽  
Scientific Practice ◽  
Measurement Theory ◽  
Quantum Measurements ◽  
Quantum Measurement Problem ◽  
Modern Physics ◽  
Conceptual Problems

Decoherence is widely felt to have something to do with the quantum measurement problem, but getting clear on just what is made difficult by the fact that the ‘measurement problem’, as traditionally presented in foundational and philosophical discussions, has become somewhat disconnected from the conceptual problems posed by real physics. This, in turn, is because quantum mechanics as discussed in textbooks and in foundational discussions has become somewhat removed from scientific practice, especially where the analysis of measurement is concerned. This paper has two goals: firstly (§§1–2), to present an account of how quantum measurements are actually dealt with in modern physics (hint: it does not involve a collapse of the wave function) and to state the measurement problem from the perspective of that account; and secondly (§§3–4), to clarify what role decoherence plays in modern measurement theory and what effect it has on the various strategies that have been proposed to solve the measurement problem.

scholarly journals ENTANGLEMENT QUANTISTICO

2020 ◽  
Author(s):  
Alberto Rimini
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum Measurement ◽  
First Principles ◽  
Measurement Problem ◽  
Entangled State ◽  
Uncertainty Relations ◽  
Entanglement State ◽  
State Uncertainty ◽  
Einstein Podolsky Rosen

This extended note deals with a pedagogical description of the entangled state of two particles, starting from first principles. After some general remarks about quantum mechanics and physical theories, the single particle case is discussed by defining state, uncertainty relations and wave function in the state space. The system of two particles is then considered, with its possible states, starting from the original papers by Einstein Podolsky Rosen and by Schroedinger. The quantum measurement problem is then introduced, together with its role in the entanglement state. Finally the orthodox solution and the relevant conclusions are drawn.

scholarly journals Measured distribution of cloud chamber tracks from radioactive decay: a new empirical approach to investigating the quantum measurement problem

2021 ◽  
Author(s):  
Jonathan Schonfeld
Keyword(s):  
Spatial Distribution ◽  
Quantum Mechanics ◽  
Quantum Measurement ◽  
Measurement Problem ◽  
Radioactive Decay ◽  
Foundations Of Quantum Mechanics ◽  
Radioactive Source ◽  
Cloud Chamber ◽  
Quantum Measurement Problem ◽  
Measured Distribution

Abstract Using publically available video of a cloud chamber with a very small radioactive source, I measure the spatial distribution of where tracks start, and consider possible implications. This is directly relevant to the quantum measurement problem and its possible resolution, and appears never to have been done before. The raw data are relatively uncontrolled, leading to caveats that should guide future, more tailored experiments. Track distributions from decays in cloud chambers represent a previously unappreciated way to probe the foundations of quantum mechanics, and a novel case of wavefunctions with macroscopic signatures.

The Collapse of the Quantum State

2019 ◽  
pp. 118-142
Author(s):  
Jeffrey A. Barrett
Keyword(s):  
Quantum Mechanics ◽  
Quantum State ◽  
Quantum Measurement ◽  
Measurement Problem ◽  
Primitive Ontology ◽  
Quantum Measurement Problem

We consider Wigner’s proposal for solving the quantum measurement problem. His solution involves a strong mind-body dualism, but it is also possible to provide a purely physical collapse solution to the quantum measurement problem. To this end, we consider the GRW formulation of quantum mechanics and three ways one might interpret it: GRWr, GRWm, and GRWf. These ways of interpreting the theory differ in the metaphysical commitments one makes and, hence, in how one explains one’s measurement records and hence one’s experience. This provides an introduction to the notions of an empirical ontology and a primitive ontology. We consider some of the comparative virtues and vices of the GRW formulation of quantum mechanics.

scholarly journals Interpretive analogies between quantum and statistical mechanics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. D. McCoy
Keyword(s):  
Quantum Mechanics ◽  
Statistical Mechanics ◽  
Quantum Measurement ◽  
Measurement Problem ◽  
Initial Conditions ◽  
Primitive Ontology ◽  
Quantum Measurement Problem ◽  
Classical Statistical Mechanics ◽  
Interpretive Strategies ◽  
Significant Application

AbstractThe conspicuous similarities between interpretive strategies in classical statistical mechanics and in quantum mechanics may be grounded on their employment of common implementations of probability. The objective probabilities which represent the underlying stochasticity of these theories can be naturally associated with three of their common formal features: initial conditions, dynamics, and observables. Various well-known interpretations of the two theories line up with particular choices among these three ways of implementing probability. This perspective has significant application to debates on primitive ontology and to the quantum measurement problem.

“This Dizzy Affair”: Quantum Measurement, Schrödinger's Cat, and Hammett's Falcon

2019 ◽  
Vol 52 (2) ◽  
pp. 261-283
Author(s):  
Brady Harrison
Keyword(s):  
Wave Function ◽  
San Francisco ◽  
Quantum Measurement ◽  
Measurement Problem ◽  
Niels Bohr ◽  
Narrative Fiction ◽  
Quantum Measurement Problem ◽  
Erwin Schrödinger ◽  
Material Reality

Abstract The article explores the so-called quantum measurement problem, or the collapse of a wave function in the act of observation, as a reading and interpretive strategy. In particular, the article argues that the Maltese falcon, if it exists at all, does not exist in Dashiell Hammett's noir version of San Francisco until Sam Spade attempts to find it in a particular place. Further, reading from a quantum perspective suggests that Casper Gutman does not really want to find the jewel-encrusted statuette, or one would have appeared more often. Drawing on the work of Niels Bohr, Erwin Schrödinger, Henry P. Stapp, and other quantum physicists, the article explores the role that consciousness and acts of observation play in the calling into being of material reality as it is imagined in narrative fiction.

scholarly journals Does Decoherence Select the Pointer Basis of a Quantum Meter?

Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 106
Author(s):  
Abraham G. Kofman ◽  
Gershon Kurizki
Keyword(s):  
Quantum Mechanics ◽  
Quantum State ◽  
Quantum Measurement ◽  
Measurement Theory ◽  
Quantum Measurements ◽  
Quantum Measurement Theory ◽  
Measuring Device ◽  
Standard Quantum ◽  
Pointer States ◽  
Projective Measurements

The consensus regarding quantum measurements rests on two statements: (i) von Neumann’s standard quantum measurement theory leaves undetermined the basis in which observables are measured, and (ii) the environmental decoherence of the measuring device (the “meter”) unambiguously determines the measuring (“pointer”) basis. The latter statement means that the environment monitors (measures) selected observables of the meter and (indirectly) of the system. Equivalently, a measured quantum state must end up in one of the “pointer states” that persist in the presence of the environment. We find that, unless we restrict ourselves to projective measurements, decoherence does not necessarily determine the pointer basis of the meter. Namely, generalized measurements commonly allow the observer to choose from a multitude of alternative pointer bases that provide the same information on the observables, regardless of decoherence. By contrast, the measured observable does not depend on the pointer basis, whether in the presence or in the absence of decoherence. These results grant further support to our notion of Quantum Lamarckism, whereby the observer’s choices play an indispensable role in quantum mechanics.

scholarly journals MEASUREMENT IN QUANTUM PHYSICS

1999 ◽  
Vol 08 (03) ◽  
pp. 257-287 ◽  
Author(s):  
MICHAEL DANOS ◽  
TIEN D. KIEU
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum Measurement ◽  
Quantum Physics ◽  
Quantum Fields ◽  
Bell’S Inequalities ◽  
Bell's Inequalities ◽  
Conceptual Problems

The conceptual problems in quantum mechanics — related to the collapse of the wave function, the particle-wave duality, the meaning of measurement — arise from the need to ascribe particle character to the wave function. As will be shown, all these problems dissolve when working instead with quantum fields, which have both wave and particle character. Otherwise the predictions of quantum physics, including Bell's inequalities, coincide with those of the conventional treatments. The process of decoherence which governs the transfer of the results of the quantum measurement to the classical realm is also carefully discussed.

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