From Quantum to Classical: Essays in Honour of H.-Dieter Zeh (Fundamental Theories of Physics, 204)

"Quantum theory is at the foundation of the physical description of our world. One of the people who contributed significantly to our conceptual understanding of this theory was Heinz-Dieter Zeh (1932-2018). He was the pioneer of the process of decoherence, through which the classical appearance of our world can be understood. This volume presents a collection of essays dedicated to his memory, written by distinguished scientists and scholars. They cover all aspects of the interpretation of quantum theory in general and the quantum-to-classical transition in particular. This volume provides illuminating reading to anyone seeking a deep understanding of quantum theory and its relevance to the foundations of physics"--Back cover Preface Contents Contributors H. Dieter Zeh and the History of the Foundations of Quantum Mechanics 1 Introduction 2 H. Dieter Zeh and the Origins of Decoherence 3 Early Reception and the Dark Ages of Decoherence 4 Decoherence and Its Interpretation 5 Decoherence and the ‘New Orthodoxy’ References Emergence of the Classical World from Within Our Quantum Universe 1 Introduction 2 Solving the Measurement Problem 3 Observers in the Classical and in the Quantum Universe 3.1 Seeing is Believing 3.2 Decoherence of Records and Information Processing 4 Quantum Darwinism, Classical Reality, and Objective Existence 4.1 Proliferation of Information and Einselection 4.2 Mutual Information in Quantum Correlations 4.3 Objective Reality from Redundant Information 4.4 Environment as a Witness 5 Discussion References Decoherence: From Interpretation to Experiment 1 Introduction 2 Interpretation 3 Experiments 4 Concluding Remarks References Experimental Decoherence in Molecule Interferometry 1 Emergence of Classical Behavior in Quantum Experiments 2 Experimental Decoherence in Macromolecule Interferometry 2.1 Coherence in the Molecular Beam 2.2 Phase Averaging and Dispersion 2.3 Decoherence Due to Internal States 2.4 Decoherence Due to the Environment 3 Perspectives in Matter-Wave Decoherence 3.1 Experimental Perspectives 3.2 Probing New Physics References When Zeh Meets Feynman: How to Avoid the Appearance of a Classical World in Gravity Experiments 1 Introduction 2 Feynman's Gedanken Experiment 3 Witten's Challenge: Becoming a Practical Experiment 4 Zeh's Decoherence: Avoiding the Appearance of a Classical World 5 Conclusion References Preferred Basis, Decoherence and the Quantum State of the Universe 1 Introduction 2 The Problem of the Preferred Basis in the Many-Worlds Interpretation of Quantum Mechanics 3 Dynamics of the Preferred Basis 4 Preferred Basis and Decoherence 5 Decoherence and Ultraviolet Divergences in Quantum Cosmology 6 Classical—Quantum Duality 7 Many-Worlds Interpretation, Probabilities and Anthropic Principle 8 Density Matrix of the Universe and the Cosmological Bootstrap 9 Concluding Remarks References Wave Function First—H. D. Zeh and the Foundations of Physics 1 H. D. Zeh and the Question About ``What Is Real?'' 2 Quantum Monism and the Foundations of Physics 3 What Is Prior? 4 It from One 4.1 Matter from One 4.2 Time from One 4.3 Space from One 4.4 Mind from One 5 Conclusion References Geometrodynamics as Functionalism About Time 1 Introduction 1.1 Three Projects 1.2 Appetizer: The Projects Introduced 1.3 Functionalist Reduction: A Review 1.4 How the Projects Illustrate Functionalist Reduction 2 Realizing the Temporal Metric—From Geometrodynamics 2.1 Hypersurface Deformations 2.2 Commutation Algebras Translated into Constraint Algebras 3 Realizing the Temporal Metric—From Matter Without Geometry 3.1 Overview of the Two Stages of Reduction 3.2 Kinematical Geometry from Matter Dynamics 3.3 Geometrodynamics from Kinematical Geometry 3.4 A Counter-Example Without Spacetime Diffeomorphism Invariance 4 Realizing the Temporal Metric—From only Spatial Geometry 4.1 Constraints on Duration 4.2 Constraints on Evolution 5 A Corollary: Shape Dynamics Exonerated 5.1 Russell's Quip 5.2 A Brief Introduction to Shape Dynamics 5.3 Shape Dynamics Exonerated 6 Conclusions 7 A The York Method References Quantum Hierarchical Systems: Fluctuation Force by Coarse-Graining, Decoherence by Correlation Noise 1 Democratic, Autocratic and Hierarchical Systems 1.1 Open Systems: Coarse-Graining and Backreaction 1.2 From Closed to Effectively Open Systems 1.3 Paradigms of Nonequilibrium Statistical Mechanics 2 Collective and Hydrodynamic Variables 2.1 Collective Variables 2.2 Hydrodynamic Variables 3 Hierarchical Systems 3.1 Structural Versus Representational Hierarchy 3.2 Correlation Hierarchy 4 Hierarchical Coarse-Graining 4.1 An Example: Atom-Field-Medium Interaction 4.2 The Medium and the Medium-Modified Field 4.3 Medium-Modified Quantum Field's Effect on the Atom 5 Quantum Hierarchical System: Correlation Noise 5.1 Boltzmann Equation for a Classical Relativistic Gas 5.2 Schwinger-Dyson Hierarchy for Interacting Quantum Fields 5.3 Master Effective Action 5.4 Decoherence by Correlation Noise and Correlation Entropy References Decoherence and the Puzzle of Quantum Brownian Motion in a Gas 1 Introduction 2 Equation of Positional Decoherence 3 Quantum Brownian Motion in a Gas 4 Complete Momentum Decoherence (CMD) 5 Collision and Methods Revisited 6 Farwell MSqR 7 Epilogue References On the Statistical Viewpoint Concerning the Second Law of Thermodynamics— A Reminder on the Ehrenfests' Urn Model 1 Prologue 2 Introduction 3 The Basic Statements 4 The Urn-Model 4.1 Future-Conditioned Probabilities and Bayes' Rule 4.2 Flow Equilibrium 4.3 Time-Reversal Invariance 5 General Consequences 5.1 Boltzmann Entropy 5.2 Consequences 1 and 2 5.3 Coarse Grained Gibbs Entropy and the H-Theorem 6 Thermodynamic Limit and Deterministic Dynamics 7 Appendix References Explanation, the Progress of Physical Theories and Computer Simulations 1 Introduction 2 Physical Theories and Explanation 2.1 Physical Symbols and Physical Theories 2.2 On the Progress of Theories 2.3 How Do We Understand Physical Theories and the Question of Explanation 2.4 Some Aspects of Explanation in Various Theoretical Schemes 2.5 Understanding and Explanation 2.6 Explanation and the Structure of Theories 2.7 A Few Words About Decoherence 2.8 On the Role of Mathematics in Physical Sciences 2.9 Closing the Circle 3 Computers in Natural Sciences 3.1 Two Moments in the History of Computers 3.2 A View on Computers in Sciences 3.3 A Brief Account of Simulation in Physics 3.4 The New Computing 3.5 What Are Computers Actually Doing? References Searching for Dieter Zeh 1 Indexing Zeh 2 Dark Days of Decoherence 3 The Email Trail References