scholarly journals Quantum Bayesianism Assessed

The Monist ◽  
2019 ◽  
Vol 102 (4) ◽  
pp. 403-423
Author(s):  
John Earman
Keyword(s):  
Quantum Mechanics ◽  
Measurement Problem ◽  
Degrees Of Belief ◽  
Quantum Probabilities

Abstract The idea that the quantum probabilities are best construed as the personal/subjective degrees of belief of Bayesian agents is an old one. In recent years the idea has been vigorously pursued by a group of physicists who fly the banner of quantum Bayesianism (QBism). The present paper aims to identify the prospects and problems of implementing QBism, and it critically assesses the claim that QBism provides a resolution (or dissolution) of some of the long-standing foundations issues in quantum mechanics, including the measurement problem and puzzles of nonlocality.

Pure Wave Mechanics

2019 ◽  
pp. 143-161
Author(s):  
Jeffrey A. Barrett
Keyword(s):  
Quantum Mechanics ◽  
Quantum Measurement ◽  
Physical Theory ◽  
Measurement Problem ◽  
Wave Mechanics ◽  
Linear Dynamics ◽  
Physical Systems ◽  
Relative State ◽  
Quantum Probabilities ◽  
Pure Wave Mechanics

Everett thought of the quantum measurement problem as one of providing a consistent description of nested measurement. He proposed solving the measurement problem by simply supposing that all physical systems whatsoever always obey the linear dynamics and hence never collapse. Dropping the collapse dynamics immediately solves the measurement problem, but it introduces two new problems: explaining determinate measurement records and explaining quantum probabilities. In addition to these, we also consider the problem of empirical coherence in the context of pure wave mechanics. We then discuss how Everett himself understood determinate records and probabilities in his relative-state formulation of pure wave mechanics. What he ultimately provided was an argument that his formulation of quantum mechanics was consistent and empirically faithful. We will see why this is a relative weak standard by which to judge the empirical adequacy of a physical theory.

Relational Blockworld and Quantum Mechanics

2018 ◽  
Author(s):  
Michael Silberstein ◽  
W.M. Stuckey ◽  
Timothy McDevitt
Keyword(s):  
Quantum Mechanics ◽  
Measurement Problem ◽  
Quantum Nonlocality ◽  
Global Constraints ◽  
Quantum Superposition ◽  
Delayed Choice ◽  
Counterfactual Definiteness ◽  
Main Thread ◽  
Block Universe ◽  
Contextual Emergence

The main thread of chapter 4 introduces some of the major mysteries and interpretational issues of quantum mechanics (QM). These mysteries and issues include: quantum superposition, quantum nonlocality, Bell’s inequality, entanglement, delayed choice, the measurement problem, and the lack of counterfactual definiteness. All these mysteries and interpretational issues of QM result from dynamical explanation in the mechanical universe and are dispatched using the authors’ adynamical explanation in the block universe, called Relational Blockworld (RBW). A possible link between RBW and quantum information theory is provided. The metaphysical underpinnings of RBW, such as contextual emergence, spatiotemporal ontological contextuality, and adynamical global constraints, are provided in Philosophy of Physics for Chapter 4. That is also where RBW is situated with respect to retrocausal accounts and it is shown that RBW is a realist, psi-epistemic account of QM. All the relevant formalism for this chapter is provided in Foundational Physics for Chapter 4.

scholarly journals A pedestrian approach to the measurement problem in quantum mechanics

2013 ◽  
Vol 38 (4) ◽  
pp. 443-470 ◽  
Author(s):  
Stephen Boughn ◽  
Marcel Reginatto
Keyword(s):  
Quantum Mechanics ◽  
Measurement Problem

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.

Collapse models tested in the LNGS underground laboratories

2019 ◽  
Vol 17 (08) ◽  
pp. 1941011
Author(s):  
Catalina Curceanu ◽  
Raffaele Del Grande ◽  
Matthias Laubenstein ◽  
Kristian Piscicchia
Keyword(s):  
Quantum Mechanics ◽  
Measurement Problem ◽  
Photon Emission ◽  
Spontaneous Radiation ◽  
Emission Data ◽  
Standard Quantum ◽  
Wave Function Collapse ◽  
X Ray ◽  
Data Analyses ◽  
Collapse Models

Collapse models consist in dynamical reformulations of the standard quantum mechanics aiming to solve the measurement problem. The standard Schrödinger dynamics is modified with the introduction of nonlinear and stochastic terms, which induce the wave function collapse in space. Collapse models predict slight deviations from the standard quantum mechanics predictions, in particular the emission of a “spontaneous radiation”, which we explored to set the most stringent limits on the collapse models parameters in a broad range. To this end, the X-ray emission data collected by the IGEX collaboration are analyzed and compared with the spectrum of the spontaneous photon emission process predicted by the theories. The results of the data analyses, and the ongoing experimental efforts will be presented.

scholarly journals Path Integrals, Spontaneous Localisation, and the Classical Limit

2020 ◽  
Vol 75 (2) ◽  
pp. 131-141 ◽  
Author(s):  
Bhavya Bhatt ◽  
Manish Ram Chander ◽  
Raj Patil ◽  
Ruchira Mishra ◽  
Shlok Nahar ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Density Matrix ◽  
Path Integral ◽  
Classical Limit ◽  
Measurement Problem ◽  
Path Integrals ◽  
Path Integral Formulation ◽  
Von Neumann ◽  
Matrix Evolution ◽  
Grw Model

AbstractThe measurement problem and the absence of macroscopic superposition are two foundational problems of quantum mechanics today. One possible solution is to consider the Ghirardi–Rimini–Weber (GRW) model of spontaneous localisation. Here, we describe how spontaneous localisation modifies the path integral formulation of density matrix evolution in quantum mechanics. We provide two new pedagogical derivations of the GRW propagator. We then show how the von Neumann equation and the Liouville equation for the density matrix arise in the quantum and classical limit, respectively, from the GRW path integral.

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.

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