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 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 A Phenomenological Reading of the Many-Worlds Interpretation of Quantum Mechanics

2020 ◽  
Author(s):  
Joaquin Trujillo
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Measurement Problem ◽  
Copenhagen Interpretation ◽  
Interpretation Of Quantum Mechanics ◽  
Many Worlds ◽  
Standard Interpretation ◽  
Hermeneutic Phenomenological ◽  
Many Worlds Interpretation ◽  
The Many

The articles provides a phenomenological reading of the Many-Worlds Interpretation (MWI) of quantum mechanics and its answer to the measurement problem, or the question of “why only one of a wave function’s probable values is observed when the system is measured.” Transcendental-phenomenological and hermeneutic-phenomenological approaches are employed. The project comprises four parts. Parts one and two review MWI and the standard (Copenhagen) interpretation of quantum mechanics. Part three reviews the phenomenologies. Part four deconstructs the hermeneutics of MWI. It agrees with the confidence the theory derives from its (1) unforgiving appropriation of the Schrödinger equation and (2) association of branching universes with the evolution of the wave function insofar as that understanding comes from the formalism itself. Part four also reveals the hermeneutical shortcomings of the standard interpretation.

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.

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.

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.

Quantum Technology: Where to Look for the Quantum Measurement Problem

1995 ◽  
Vol 38 ◽  
pp. 73-83
Author(s):  
Nancy Cartwright
Keyword(s):  
Quantum Mechanics ◽  
Quantum Measurement ◽  
Philosophy Of Technology ◽  
Measurement Problem ◽  
Mathematical Structure ◽  
Point Of View ◽  
Philosophy Of Physics ◽  
Unitary Operators ◽  
Quantum Technology ◽  
Philosophical Importance

This paper, I am afraid, advocates the philosophy of technology without actually doing it. It can best be seen as a plea for the philosophical importance of technology; in this case, importance to one of the most widely discussed problems in philosophy of physics—the measurement problem in quantum mechanics. What I want to do here is to lay out a point of view that takes the measurement problem out of the abstract mathematical structure of theory, where we discuss questions about unitary operators or conditions for the disappearance of certain inner products supposed to represent interference terms, and locate it elsewhere. Where is the measurement problem? Answer: It had better be found in the quantum technology or it is not to be found at all. My view in many respects follows ideas I have learned from Willis Lamb.

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.

scholarly journals Orbital angular momentum uncertainty relations of entangled two-photon states

2021 ◽  
Vol 75 (8) ◽  
Author(s):  
Wei Li ◽  
Shengmei Zhao
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Composite System ◽  
Entangled State ◽  
Uncertainty Relations ◽  
Epr Paradox ◽  
Photon State ◽  
Two Photon ◽  
Einstein Podolsky Rosen ◽  
Photon States

Abstract The inseparability of quantum correlation requires that the particles in the composite system be treated as a whole rather than treated separately, a typical example is the Einstein–Podolsky–Rosen (EPR) paradox. In this paper, we provide a theoretical study on the uncertainty relations of two kinds of bipartite observables in two-photon orbital angular momentum (OAM) entanglement, that is, the relative distance and centroid of the two photons at azimuth. We find that the uncertainty relations of the bipartite observables holds in any two-photon state, and they are separable in two-photon OAM entanglement. In addition, the entangled state behaves as a single particle in the bipartite representation. Finally, we find that the uncertainty relations of the bipartite observables can be used to manipulate the degree of the entanglement of an EPR state. Graphic abstract

Quantum Measurement and Entanglement: Wave Function Collapse

2021 ◽  
pp. 220-229
Author(s):  
Duncan G. Steel
Keyword(s):  
Wave Function ◽  
Quantum Computing ◽  
Quantum Entanglement ◽  
Quantum Measurement ◽  
Projection Operator ◽  
Entangled State ◽  
Epr Paradox ◽  
Wave Function Collapse ◽  
Von Neumann ◽  
Quantum Encryption

The postulates presented at this point are generally agreed upon as being the primary set. But in the course of these postulates, there is no mention of the consequences of measurement. This chapter discusses this problem and the solution as provided by the Von-Neumann postulate. The concept of the projection operator is introduced, and this leads naturally to the study of the quantum entangled state. The results show in part the origin of the struggle that Einstein and others had with quantum, and the Einstein, Podolsky, and Rosen (EPR) paradox. Quantum entanglement is the key to advanced ideas in quantum encryption, teleportation, and quantum computing.

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