Book contents
- Frontmatter
- Contents
- List of papers on quantum philosophy by J. S. Bell
- Preface to the first edition
- Acknowledgements
- Introduction: John Bell and the second quantum revolution
- 1 On the problem of hidden variables in quantum mechanics
- 2 On the Einstein–Podolsky–Rosen paradox
- 3 The moral aspect of quantum mechanics
- 4 Introduction to the hidden-variable question
- 5 Subject and object
- 6 On wave packet reduction in the Coleman–Hepp model
- 7 The theory of local beables
- 8 Locality in quantum mechanics: reply to critics
- 9 How to teach special relativity
- 10 Einstein–Podolsky–Rosen experiments
- 11 The measurement theory of Everett and de Broglie's pilot wave
- 12 Free variables and local causality
- 13 Atomic-cascade photons and quantum-mechanical nonlocality
- 14 de Broglie–Bohm, delayed-choice double-slit experiment, and density matrix
- 15 Quantum mechanics for cosmologists
- 16 Bertlmann's socks and the nature of reality
- 17 On the impossible pilot wave
- 18 Speakable and unspeakable in quantum mechanics
- 19 Beables for quantum field theory
- 20 Six possible worlds of quantum mechanics
- 21 EPR correlations and EPW distributions
- 22 Are there quantum jumps?
- 23 Against ‘measurement’
- 24 La nouvelle cuisine
14 - de Broglie–Bohm, delayed-choice double-slit experiment, and density matrix
Published online by Cambridge University Press: 11 April 2011
- Frontmatter
- Contents
- List of papers on quantum philosophy by J. S. Bell
- Preface to the first edition
- Acknowledgements
- Introduction: John Bell and the second quantum revolution
- 1 On the problem of hidden variables in quantum mechanics
- 2 On the Einstein–Podolsky–Rosen paradox
- 3 The moral aspect of quantum mechanics
- 4 Introduction to the hidden-variable question
- 5 Subject and object
- 6 On wave packet reduction in the Coleman–Hepp model
- 7 The theory of local beables
- 8 Locality in quantum mechanics: reply to critics
- 9 How to teach special relativity
- 10 Einstein–Podolsky–Rosen experiments
- 11 The measurement theory of Everett and de Broglie's pilot wave
- 12 Free variables and local causality
- 13 Atomic-cascade photons and quantum-mechanical nonlocality
- 14 de Broglie–Bohm, delayed-choice double-slit experiment, and density matrix
- 15 Quantum mechanics for cosmologists
- 16 Bertlmann's socks and the nature of reality
- 17 On the impossible pilot wave
- 18 Speakable and unspeakable in quantum mechanics
- 19 Beables for quantum field theory
- 20 Six possible worlds of quantum mechanics
- 21 EPR correlations and EPW distributions
- 22 Are there quantum jumps?
- 23 Against ‘measurement’
- 24 La nouvelle cuisine
Summary
I will try to interest you in the de Broglie–Bohm version of non-relativistic quantum mechanics. It is, in my opinion, very instructive. It is experimentally equivalent to the usual version insofar as the latter is unambiguous. But it does not require, in its very formulation, a vague division of the world into ‘system’ and ‘apparatus,’ nor of history into ‘measurement’ and ‘nonmeasurement.’ So it applies to the world at large, and not just to idealized laboratory procedures. Indeed the de Broglie–Bohm theory is sharp where the usual one is fuzzy, and general where the usual one is special. This is not a systematic exposition, but only an illustration of the ideas with a particularly nice example, and then some remarks on the role of the density matrix – in tribute to the title of this conference.
No one more eloquently than John A. Wheeler has presented the delayed-choice double slit experiment. A pulsed particle source S (see Fig. 1) is so feeble that not more than one particle is emitted per pulse. The associated wave pulse B falls on a screen with slits 1 and 2. The transmitted pulses B′ are focussed by off-centred lenses into intersecting plane wave trains which fall finally on particle counters C1 and C2 – unless a photographic plate P is pushed into the region where the two wave trains interpenetrate. The decision, to interpose the plate or not, is made only after the pulse has passed the slits.
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- Information
- Speakable and Unspeakable in Quantum MechanicsCollected Papers on Quantum Philosophy, pp. 111 - 116Publisher: Cambridge University PressPrint publication year: 2004
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