The arrow of time: The role of measuring

Lawrence S. Schulman

This book is an introduction to the arrow of time in thermodynamics and cosmology, and develops a new quantum measurement theory in which the foregoing concepts play an essential role. The first chapter is an overview and 'route map' and is followed by an exposition of irreversibility, the expansion of the Universe and other arrows of time. The author examines the thesis that the thermodynamic arrow follows the cosmological one, and in doing so extends traditional statistical mechanics. The second part of the book presents a new theory of quantum measurement and possible experimental tests. This theory incorporates the extended statistical mechanics in an essential way. The last chapter discusses open experimental and theoretical issues. Written in a lively and accessible style, the text is liberally sprinkled with exercises. Each chapter ends with a resources section that includes notes, further reading, and technical appendices.

Tarek Halabi

Zhen Wang

A generalized framework is developed which uses a set description instead of wavefunction to emphasize the role of the observer. Such a framework is found to be very effective in the study of the measurement problem and time's arrow. Measurement in classical and quantum theory is given a unified treatment. With the introduction of the concept of uncertainty quantum which is the basic unit of measurement, we show that the time's arrow within the uncertainty quantum is just opposite to the time's arrow in the observable reality. A special constant is discussed which explains our sensation of time and provides a permanent substrate for all change. It is shown that the whole spacetime connects together in a delicate structure.

Henriksson, Andreas

What is the physical origin of the arrow of time? It is a commonly held belief in the physics community that it relates to the increase of entropy as it appears in the statistical interpretation of the second law of thermodynamics. At the same time, the subjective information-theoretical interpretation of probability, and hence entropy, is a standard viewpoint in the foundations of statistical mechanics. In this article, it is argued that the subjective interpretation is incompatible with the philosophical point of view that the arrow of time is a fundamental property of Nature. The subjectivist can only uphold this philosophy if the role played by the second law of thermodynamics in defining time's arrow is abandoned.

Zack Savitsky