Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1701.00781 · AIP conference proceedings

Quantum measurement and weak values in entropic dynamics

Kevin Vanslette, Ariel Caticha

Published Jan 1, 2017• 17 citations
arXivHTMLPDF

Abstract

The problem of measurement in quantum mechanics is studied within the Entropic Dynamics framework. We discuss von Neumann and Weak measurements, wavefunction collapse, and Weak Values as examples of bayesian and entropic inference.
DOI
10.1063/1.4985372

Related papers

Entropic Dynamics and Quantum “Measurement”

Ariel Caticha

The entropic dynamics (ED) approach to quantum mechanics is ideally suited to address the problem of measurement because it is based on entropic and Bayesian methods of inference that have been designed to process information and data. The approach succeeds because ED achieves a clear-cut separation between ontic and epistemic elements: positions are ontic, while probabilities and wave functions are epistemic. Thus, ED is a viable realist ψ-epistemic model. Such models are widely assumed to be ruled out by various no-go theorems. We show that ED evades those theorems by adopting purely epistemic dynamics and denying the existence of an ontic dynamics at the subquantum level.

arXiv:2208.02156•International Workshop on Bayesian Inference and Maximum Entropy Methods in Science and Engineering (MaxEnt)•Dec 15, 2022•3 citations

Entropic dynamics and the quantum measurement problem

David T. Johnson, Ariel Caticha

We explore the old quantum measurement problem from the perspective of entropic dynamics. The entropic approach contributes two new ideas. First, the dual modes of quantum evolution-either continuous unitary evolution or abrupt wave function collapse during measurement-are unified by virtue of both being special instances of entropic updating of probabilities. The second new idea is that in entropic dynamics particles have only one attribute-position. They have neither momentum nor energy nor any other attributes. The positions have definite albeit unknown values; they are not created by the act of measurement. Other so-called observables can of course be introduced but only as a convenient way to describe more complex position measurements; they are attributes not of the particles but of the probability distributions; their values are effectively created by the act of measurement. We discuss the Born statistical rule for position, which is trivially built into the formalism, and also for more generic observables.

arXiv:1108.2550•AIP conference proceedings•Jan 1, 2012•22 citations

Weak values and weak measurements in quantum mechanics

Ludvík Vízdal

The main goal of this thesis is to introdude to readers the concept of weak measure- ments in quantum mechanics. Firstly a model of indirect measuremnts is established as an alternative to Von Neumann measurement postulate. This model leads to a possible generalization in a form of weak measurements. Then the concept of postselection is introduced and involved into the issue of weak measurements which leads to the weak values of physical quantities. All these theoretical concepts are presented using simple model examples. Finally, a discussion in provided on the possible interpretation and of weak values and their experimental verification.

•Jan 1, 2024•0 citations

Decoherence and Quantum Measurement: The Missing Lecture

Stephen D. H. Hsu

We give an elementary account of quantum measurement and related topics from the modern perspective of decoherence. The discussion should be comprehensible to students who have completed a basic course in quantum mechanics with exposure to concepts such as Hilbert space, density matrices, and von Neumann projection (``wavefunction collapse'').

arXiv:2212.02391•Dec 5, 2022•0 citations

Weak measurements: From measuring incompatible observables and testing quantum contextuality to protective measurements

Fabrizio Piacentini, Alessio Avella, Rudi Lussana +9 more

Summary form only given. Measurements are the very basis of Physics, especially in Quantum Mechanics, where they assume even a more fundamental role because of wave function collapse after a “strong” (projective) measurement. Furthermore, measuring a quantum-mechanical observable completely erases the information on its conjugate one (e.g. measurement of position erases information on momentum, and vice-versa). Nevertheless, in Quantum Mechanics other kinds of measurement are possible. For example, wave function collapse can be overcome through Weak Measurements, i.e. measurements performed with an interaction sufficiently weak not to collapse the original state, featuring several interesting properties. An example of these are weak values [1-3], realised for the first time in [4-6], that have been used for addressing fundamental questions [7-12] as Contextuality and are also a tool for Quantum Metrology [13-19]. One of the most intriguing properties of Weak Measurements is that, since they are not affected by wave function collapse, they can allow gathering simultaneous information on non-commuting observables [20], impossible with the standard (projective) measurement protocols. A second example is offered by Protective Measurements [21], a new technique able to extract information on the expectation value of an observable even measuring a single particle. In this talk, after a general introduction to WMs, we present the first realisation of sequential weak value measurements [22], i.e. a joint measurement of the weak value of (incompatible) polarizations on a single photon. Then, we present an experiment addressed to explore the connection between anomalous weak values and Contextuality [23], showing a clear violation of the inequality proposed in [12] while satisfying all the additional theoretical requests, unequivocally demonstrating the contextual nature of weak values. Finally, we present and discuss the first implementation of Protective Measurements, showing unprecedented measurement capability and demonstrating how the expectation value of an observable can be obtained with a single measurement on a single particle.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2017•0 citations

Role of weak values in strong measurements

F. De Zela

The physical meaning of the quantum weak value still remains a matter of debate. Originally introduced by Aharonov et al. [Phys. Rev. Lett. 60, 1351 (1988).] as another counterintuitive feature of quantum mechanics, it eventually evolved into a practical tool that is widely used. The theoretical framework in which weak values were introduced was given by von Neumann's model of quantum measurements. In this model, a system is submitted to measurement by coupling it to a ``pointer,'' or meter. In the weak-coupling regime, one may perform a low-order Taylor expansion for the evolution operator of the system and meter. This standard approach ties weak values with weak couplings and weak measurements. We report closed-form expressions that can be used to untie weak values from weak measurements. The regime of strong measurements thereby becomes accessible to weak values, without leaving the framework in which the latter were originally introduced. The reported results should also help us to better understand the physical meaning of weak values.

Physical Review A•Apr 4, 2022•12 citations
The entropic dynamics (ED) approach to quantum mechanics is ideally suited to address the problem of measurement because it is based on entropic and Bayesian methods of inference that have been designed to process information and data. The approach succeeds because ED achieves a clear-cut separation between ontic and epistemic elements: positions are ontic, while probabilities and wave functions are epistemic. Thus, ED is a viable realist ψ-epistemic model. Such models are widely assumed to be ruled out by various no-go theorems. We show that ED evades those theorems by adopting purely epistemic dynamics and denying the existence of an ontic dynamics at the subquantum level.
We explore the old quantum measurement problem from the perspective of entropic dynamics. The entropic approach contributes two new ideas. First, the dual modes of quantum evolution-either continuous unitary evolution or abrupt wave function collapse during measurement-are unified by virtue of both being special instances of entropic updating of probabilities. The second new idea is that in entropic dynamics particles have only one attribute-position. They have neither momentum nor energy nor any other attributes. The positions have definite albeit unknown values; they are not created by the act of measurement. Other so-called observables can of course be introduced but only as a convenient way to describe more complex position measurements; they are attributes not of the particles but of the probability distributions; their values are effectively created by the act of measurement. We discuss the Born statistical rule for position, which is trivially built into the formalism, and also for more generic observables.
The main goal of this thesis is to introdude to readers the concept of weak measure- ments in quantum mechanics. Firstly a model of indirect measuremnts is established as an alternative to Von Neumann measurement postulate. This model leads to a possible generalization in a form of weak measurements. Then the concept of postselection is introduced and involved into the issue of weak measurements which leads to the weak values of physical quantities. All these theoretical concepts are presented using simple model examples. Finally, a discussion in provided on the possible interpretation and of weak values and their experimental verification.
Summary form only given. Measurements are the very basis of Physics, especially in Quantum Mechanics, where they assume even a more fundamental role because of wave function collapse after a “strong” (projective) measurement. Furthermore, measuring a quantum-mechanical observable completely erases the information on its conjugate one (e.g. measurement of position erases information on momentum, and vice-versa). Nevertheless, in Quantum Mechanics other kinds of measurement are possible. For example, wave function collapse can be overcome through Weak Measurements, i.e. measurements performed with an interaction sufficiently weak not to collapse the original state, featuring several interesting properties. An example of these are weak values [1-3], realised for the first time in [4-6], that have been used for addressing fundamental questions [7-12] as Contextuality and are also a tool for Quantum Metrology [13-19]. One of the most intriguing properties of Weak Measurements is that, since they are not affected by wave function collapse, they can allow gathering simultaneous information on non-commuting observables [20], impossible with the standard (projective) measurement protocols. A second example is offered by Protective Measurements [21], a new technique able to extract information on the expectation value of an observable even measuring a single particle. In this talk, after a general introduction to WMs, we present the first realisation of sequential weak value measurements [22], i.e. a joint measurement of the weak value of (incompatible) polarizations on a single photon. Then, we present an experiment addressed to explore the connection between anomalous weak values and Contextuality [23], showing a clear violation of the inequality proposed in [12] while satisfying all the additional theoretical requests, unequivocally demonstrating the contextual nature of weak values. Finally, we present and discuss the first implementation of Protective Measurements, showing unprecedented measurement capability and demonstrating how the expectation value of an observable can be obtained with a single measurement on a single particle.
The physical meaning of the quantum weak value still remains a matter of debate. Originally introduced by Aharonov et al. [Phys. Rev. Lett. 60, 1351 (1988).] as another counterintuitive feature of quantum mechanics, it eventually evolved into a practical tool that is widely used. The theoretical framework in which weak values were introduced was given by von Neumann's model of quantum measurements. In this model, a system is submitted to measurement by coupling it to a ``pointer,'' or meter. In the weak-coupling regime, one may perform a low-order Taylor expansion for the evolution operator of the system and meter. This standard approach ties weak values with weak couplings and weak measurements. We report closed-form expressions that can be used to untie weak values from weak measurements. The regime of strong measurements thereby becomes accessible to weak values, without leaving the framework in which the latter were originally introduced. The reported results should also help us to better understand the physical meaning of weak values.