The Physical Basis of The Direction of TimeFour previous editions of this book were published in 1989, 1992, 1999, and 2001. They were preceded by a German version (Zeh 1984) that was based on lectures I had given at the University of Heidelberg. My interest in this subject arose originally from the endeavor to better - derstand all aspects of irreversibility that might be relevant for the statistical natureandinterpretationofquantumtheory. Thequantummeasurementp- cess is often claimed to represent an ‘ampli?cation’ of microscopic properties to the macroscopic scale in close analogy to the origin of classical ?uctuations, whichmayleadtothelocalonsetofaphasetransition,forexample. Thisclaim can hardly be upheld under the assumption of universal unitary dynamics, as is well known from the example of Schr ̈ odinger’s cat. However, the classical theoryofstatisticalmechanicso?ersmanyproblemsandmisinterpretationsof its own, which are in turn related to the oft-debated retardation of radiation, irreversible black holes with their thermodynamical aspects, and – last but not least – the expansion of the Universe. So the subject o?ered a great and exciting ‘interdisciplinary’ challenge. My interest was also stimulated by Paul Davies’ (1977) book that I used successfully for my early lectures. Quantum gravity, that for consistency has to be taken into account in cosmology, even requires a complete revision of the concept of time, which leads to entirely novel and fundamental questions of interpretation (Sect. 6. 2). Many of these interesting ?elds and applications have seen considerable progress since the last edition came out. |
Contents
| 1 | |
The Physical Concept of Time | 11 |
The Time Arrow of Radiation | 17 |
The Thermodynamical Arrow of Time | 39 |
The Quantum Mechanical Arrow of Time | 85 |
The Time Arrow of Spacetime Geometry | 135 |
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Common terms and phrases
absorber accelerated according appear applied approximation argument arrow assumed black hole boundary causality characterize charge classical closed collapse complete concept condition consequence conserved consistent constant contrast coordinates correlations corresponding cosmology decay decoherence defined density depends derived described determinism direction discussed distribution dynamical effective elements energy ensemble entanglement entropy environment equation equivalent example existence explain field forces formal fundamental future given global gravity Hamiltonian horizon important initial initial condition interaction interpretation irreversible laws lead light limit macroscopic mass matrix matter means measurement motion Nature objects observed obtains operators particle past phase physical position potential probability problem quantum mechanical quantum theory radiation region relativity relevant remain represent respect result retarded reversal Schrödinger Sect similar singularity solution sources space spacetime spatial statistical superposition symmetry theory thermodynamical tion trajectories transformation universe usually variables wave function
Popular passages
Page 6 - ... position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.
Page 6 - A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended is its area of applicability. Therefore the deep impression which classical thermodynamics made upon me. It is the only physical theory of universal content concerning which I am convinced that, within the framework of the applicability of its basic concepts, it will never be overthrown (for the special attention of those who are skeptics on principle).
Page 6 - The law that entropy always increases — the second law of thermodynamics — holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equation — then so much the worse for Maxwell's equation.