Book contents
- The Arrow of Time
- The Arrow of Time
- Copyright page
- Contents
- Contributors
- Preface
- Acknowledgments
- Part I Local Systems
- 1 The Direction of Time: From the Cosmos to Local Systems
- 2 Thermodynamics with and without Irreversibility
- 3 Thermodynamics without Time
- Part II The Arrow of Time and Philosophical Issues
- Part III The Arrow of Time and Time-Reversal Invariance
- Part IV The Whole Universe
- Index
- References
3 - Thermodynamics without Time
from Part I - Local Systems
Published online by Cambridge University Press: 28 October 2025
Book contents
- The Arrow of Time
- The Arrow of Time
- Copyright page
- Contents
- Contributors
- Preface
- Acknowledgments
- Part I Local Systems
- 1 The Direction of Time: From the Cosmos to Local Systems
- 2 Thermodynamics with and without Irreversibility
- 3 Thermodynamics without Time
- Part II The Arrow of Time and Philosophical Issues
- Part III The Arrow of Time and Time-Reversal Invariance
- Part IV The Whole Universe
- Index
- References
Summary
Our fundamental theories, that is, the quantum theory and general relativity, are invariant under time reversal. Only when we treat systems from the point of view of thermodynamics, that is, averaging between many subsystem components, an arrow of time emerges. The relation between thermodynamic and the quantum theory has been fertile, deeply explored and still a source of new investigations. The relation between the quantum theory and gravity, while it has not yet brought an established theory of quantum gravity, has certainly sparked in-depth analysis and tentative new theories. On the other hand, the connection between gravity and thermodynamics is less investigated and more puzzling. I review a selection of results in covariant thermodynamics, such as the construction of a covariant notion of thermal equilibrium by considering tripartite systems. I discuss how such construction requires a relational take on thermodynamics, similar to what happens in the quantum theory and in gravity.
Information
- Type
- Chapter
- Information
- The Arrow of TimeFrom Local Systems to the Whole Universe, pp. 56 - 70Publisher: Cambridge University PressPrint publication year: 2025
References
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