Relativistic Quantum Measurement and Decoherence: Lectures of a Workshop Held at the Istituto Italiono per gli Studi Filosofici, Naples, April 9-10, 1999

Heinz-Peter Breuer, Francesco Petruccione3540410619, 9783540410614

The development of a consistent picture for the processes of decoherence and quantum measurement requires a treatment which is compatible with the theory of relativity. This volume reviews some of the approaches suggested to solve or circumvent the arising difficulties. Starting from an analysis of the level of compatibility of the measurement problem with the special theory of relativity, the role of non-locality and entanglement are discussed. The subject is also addressed from the point of view of quantum optics and quantum information theory, as well as on the basis of group theoretic and algebraic methods. The emergence of decoherence in quantum electrodynamics is discussed from an open systems perspective.

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Table of contents :
Preface……Page 1
List of Participants……Page 2
Contents……Page 4
1 The Measurement Problem……Page 6
2 Degrees of Compatibility with Special Relativity……Page 8
3 The Theory I H ve in Mind……Page 13
4 Approximate Compatibility with Special Relativity……Page 15
References……Page 18
1 Introduction……Page 19
2 Parametric Down-Conversion and Entanglement Swapping……Page 21
3 Event-Ready Entanglement……Page 25
4 Conclusions……Page 29
Appendix:Transformation of Maximally Entangled States……Page 30
References……Page 32
1 Introduction……Page 34
2 Reduced Density Matrix of the Matter Degrees of Freedom……Page 36
3 The In .uence Phase Functional of QED……Page 38
4.1 Representation of the Electron Density Matrix in the Non-Relativistic Approximation……Page 44
4.2 The Path Integral Representation……Page 46
4.3 The Abraham-Lorentz Equation……Page 48
4.4 Construction of the Decoherence Function……Page 50
5.1 Determination of the Decoherence Function……Page 54
5.2 Wave Packet Propagation……Page 58
6 The Harmonically Bound Electron in the Radiation Field……Page 63
7 Destruction of Coherence of Many-Particle States……Page 64
8 Conclusions……Page 65
References……Page 67
1 Introduction……Page 69
2.1 Superselection Rules……Page 71
Gaining intuition in .nite dimensions…….Page 74
The general case…….Page 77
2.3 Dirac ’s Condition and Gauge Symmetries……Page 78
Non-abelian gauge groups……Page 79
3 Superselection Rules via Symmetry Requirements……Page 81
4 Bargmann ’s Superselection Rule……Page 83
5 Charge Superselection Rule……Page 87
References……Page 92
1 Introduction……Page 94
2 Partial Ordering of Quantum Histories……Page 95
3 Consistent Histories……Page 96
4 Consistent Sets and Contrary Inferences:A Brief Review……Page 98
5 Relation of Contrary Inferences and Subspace Implications……Page 102
6 Ordered Consistent Sets of Histories……Page 103
7 Ordered Consistent Sets and Quasiclassicality……Page 105
8 Ordering and Ordering Violations:Interpretation……Page 109
9 Conclusions……Page 111
Appendix:Ordering and Decoherence Functionals……Page 112
References……Page 115
1 Introduction……Page 117
2 Measurements on 2-Particle Systems with Parallel or Anti-Parallel Spins……Page 118
References……Page 123
1 Massive Field Heat Bath and Two Level System……Page 124
2 Spin-1/2 System……Page 125
3 Oscillator……Page 130
4 Spin Boson Problem……Page 132
5 Instantaneous Change……Page 135
6 Discussion……Page 137
References……Page 139