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Quantum Physics: Illusion or Reality? (Canto)

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I'm not a math physics person, but I enjoy learning what I can about them, which is why I purchased this book. I almost put it aside as I felt some of the first few pages were over my head, but I decided to look upon it as stretching exercises for the mind, and managed to reach a tolerable comprehension of the material. Thereafter the book was both understandable and thoroughly readible. I found intriguing the philosophical implications of quantum physics. Particularly interesting was the author's discussion of Popper and Eccles's concepts of the 3 worlds of reality: the world of objects, of the human mind and of the products of the human mind. The implication of human consciousness in cetain physical interactions and the possiblity that consciousness actually creates reality itself was the topic of several pages. The author also briefly touches upon artificial intelligence, multiple-world hypothesis, the effect of size on expected theoretical outcomes, and time and its direction. It was a thoroughly enjoyable book.

Since the formulation of quantum theory in the 1920s the Copenhagen Interpretation of reality has been the mainstream view among physicists. But this interpretation has been uncomfortable for many, because it raises a number of paradoxes. The lack of cause and effect, (indeterminism), the so called "observer effect (quantum measurement problem), and non-locality, are among them.
Waisting no time in this 118 page book, Alastair Rae grabs the reader in the very first sentence of the book by quoting Albert Einstein's famous pronouncement: "Does God play dice [with the universe]?"
Using impeccable logic and only a bit of mathematical jargon, which can be circumvented by the reader, Rae sets out to solve many of these paradoxes. Citing experiments with polarized photons of light, he asks: What exactly constitutes a measurement? Does a measurement occur when a record is made? Or does it take consciousness to collapse the wave into a definitive particle? Is there a resolution to the Schrodinger's Cat paradox? How can we explain nonlocality?
Rae systematically entertains and rebuts in a convincing and objective way many different philosophies put forward to make sense of quantum reality. Some have claimed, most notably Niels Bohr, that it's the interaction of the partilce with a macor-measuring device that instigates the collapse. Others believe that it takes a consciousness to create reality. Still others, looking for a way to save determinism, and circumvent the measurement problem latch on to Hugh Everett's many-world interpetation.
Ironically as Rae points out most scientists claim to be "positivists", believing that it is meaningless to speculate on unobservable quantities. yet, they apparently have no problem believing in a myriad of unobservable and unmeasureable universes, completely and irreversibly cut off from our own.
In the final two chapters Rae objectively entertains what he believes is the most likely resolution of the quantum measurement problem. His idea was first proposed by Ilya Prigonine who won the Nobel Prize for his work in the field of irreversible chemical thermodynamics. The classical idea put forward by Prigonine states that there is an irreversible arrow of time and the second law of thermodynamics is never violated. Citing Prigonine's work, Rae explains: If no measurement is made of a quantum system no impression has been made on the universe, and the information which could have been obtained can be reversed and destroyed. If, however, a measurement is made, a change of some sort has occurred, either in the measuring device or our brain. The measurement has impacted the universe in some manner, and as a result the macro system must now follow the second law of thermodynamics, which has and arrow of time and hence is irreversible.
Rae states that "if we follow Prigogine's approach, indeterminism becomes an implicit part of classical physics.
Has Alastair Rae accomplished what he set out to do in this Book? Not quite. At the beginning of the book he states that he will tackle the problem of indeterminism, yet he spends most of his time attempting to explain the quantum measurement problem which is something quite different. And when he does address determinsim it falls short on several points.
First, a Prigogine macro system is indeed unpredictable, but it is not indeterminate as Rae seems to imply. Rather, it is a determinate and irreversible system having and arrow of time and an initial cause, no matter how subtle.
Secondly, he fails to address the process of nuclear decay, and the jump of the electron from one orbit to another--both of which are "real" and indeterminate.
Finally, in regard to the quantum measurement problem. Rae does not take into account recent experiments done with photons as cited in Scientific American (November 1991). In this particular experimental set-up at the Universtity of Rochester, researchers demonstrated that "The mere possibility that the paths can be distinguished is enough to wipe out the interference pattern." There is no measurement made, no record made, and no interaction with a macro system. Yet, the collapse of the wave happens without interacting with a macro sytem. Therefore, it seems that Ray's explanation of a resolution to the problem by creating a record in a classical Prigogine system is invalid.
This is still a very well written, concise, and provacative book and I would recommend it for those who want to understand the basic principles and paradoxes of quantum reality. This review written by: Quantum Reality1, author of "Quantum Reality: A New Philosophical Perspective."

Bringing complex topics to a level where they can be understood by beginners is an art. Alastair Rae does just that, and should be congratulated for it. His chronological explanations of the basic Quantum Physics notions make you feel welcome in a field of Science otherwise perceived as closed to most novices.

Be warned, this book assumes you know a little about quantum physics to begin with. It's not going to walk you through all the basics of the field. But for those who've had an introduction to the concepts of quantum physics, it's a great examination of the conceptual problems of quantum physics. Don't be fooled by its short length -- this is a book to be read slowly, re-read, an digested. The discussion of the EPR paradox and Bell's Theory is especially good, because it's more technical and mathematical than those in other intro books, and while therefore more difficult, it's also more rewarding.

It has only been once in a great while that a thin little tome has taught me so much, and been so much fun. Before Quantum Physics by Alastair Rae, the last one I remember was Richard Feynmann's QED. I now feel like I have at least a near understanding of Bell's Theorem, EPR, SQUIDS, and an assortment of things and concepts that were tantalizing but vague until now. Thank you, Alastair, you're a good teacher. And, the little surprise at the end, Prigogine's possible answer. I'd always found him intriguing. Now I know why.

I have read many books about the subject, they were ok but always missing something. I found this book as complete as it can be. His coverage for non-locality, EPR paradox, Bell's theorem,and the many interpretations of the quantum mechanics (Copenhagen, many worlds, Wigner's interpretation relating to the mind of the observer...) are well presented and heavily explained. I recomend this book to all the readers in physics. I hope that you will enjoy as I did.

A. Rae struggles with the conceptual and philosophical implications of quantum physics (qf).
His book contains excellent explanations of the destruction of determinism, because uncertainty and indeteterminism are built into qf's very foundations. He also rejects the 'hidden variables' solution to solve qf's apparent contradictions. He shows also the fundamental opposition between Einstein and Bohr.
Unfortunately, this book contains a comment on the out-of-date Popper-Eccles discussion on the body/mind problem and their statement that the mind is not subject to the laws of physics. This problem has been resolved (see V. Ramachandran's linguistic solution in 'Phantoms in the brain', or G. Edelman's 'A universe of consciousness').
But I found certain flaws in the author's reasoning due mainly to the choice of bad examples.
Firstly, let me state one fundamental specification: reality is a process, not a fact (L. Smolin).
That is the reason why his ultimate question 'If reality is only what is observed ...' is not a good one.
A qf measurement does not create the 'only' reality. Protons, electrons, dead or alive cats, DNA mutations exist, even if they are not observed. A qf measurement is part of the universal process. In qf we only measure complementarities (properties) as Bohr stated.
Secondly, A. Rae states that macroscopic processes are irreversible (the second law of thermodynamics) and microscopic ones reversible.
For reversibility he chooses as example the collision of two molecules. I doubt firmly that in our universe after the collision the molecules can (without an exterior intervention) go back to their initial states. Those interactions are 'theoretically' reversible.
On the other hand, the life or death of a cat is a macroscopic event. The cat example is a good 'figure' to explain the qf theory, but it is a bad one to build a conceptual or philosophical theory on it. Nobody will calculate the outcome of a certain event based on a dead/alive scenario if a simple look at the cat's condition can eliminate 50% of the possibilities. The same goes for the DNA mutations.
The theory of I. Prigogyne (his books are difficult) is certainly a step in the good direction. As reality is a process, indeterminism should also be the fundamental cornerstone for classical physics, but naturally not in our daily Euclidian life.
In the case of the 'many worlds' question, I prefer Rudolf Peierls's solution where he proposes to speak of many world 'possibilities' (see P. Davies' 'The ghost in the atom').
This is a thought-provoking book. Not to be missed.

In terms of classical physics, the physical reality may be defined as matter and energy behaving according to the laws of physics in classical spacetime, and the human being is a passive observer of this reality. According to quantum physics, matter and energy behave according to the laws of quantum physics in quantized spacetime, and the human observer is an integral part of this reality: The quantum physics include consciousness as an integral part of its laws.

In this book the author discusses the deficiencies of two major interpretations of quantum physics: The Copenhagen interpretation expounded by Niels Bohr and the Many worlds' interpretation proposed by Hugh Everett III. The author also discusses a third hypothesis called the consistent histories approach. The book starts with a traditional text book style introduction to Young's double slit experiments. In a popular book such as this, it is a turn off, because an ordinary reader would like to read more about the descriptive part rather than the experimental part. Complicating this further, some chapters require reasonable knowledge of physics and mathematics and an interest in experimental physics to appreciate the subject matter.

The quantum physical problem arises from how elementary particles at the microscopic level (quantum physics) are measured from the macroscopic instruments (classical physics). In the quantum world, an elementary particle or a collection of such particles can exist in a superposition of two or more possible states of physical being. It can be in a superposition of different locations, velocities and orientations of its spin anywhere in the universe, but when we measure one of these properties we see one of the elements of the superposition, but not a combination of them. The measuring macroscopic object will not be in this superposition. How do we explain this unique world of reality emerge from the multiplicities of alternative superposed quantum states? The wave functions that represent each quantum state treat each element of the superposition as equally real (but not necessarily equally probable.)

The Schrödinger equation delineates how a quantum system's wave function will change through time. This predicts a smooth and deterministic (no randomness) change. But mathematics contradicts this when humans observe a quantum system with an instrument. At the moment of measurement, the wave function describing the superposition of all states collapse into one member of the superposition, thus interrupting the smooth evolution of the wave function and introducing discontinuity in the system. The selected state at the moment of measurement is arbitrary, and its emergence does not evolve logically from the information packed wave function of the particle. In addition, the mathematics of collapse does not emerge from the seamless flow of the Schrödinger equation, but collapse has to be added as an additional process that seems to violate the equation. This is the main argument of the Copenhagen interpretation. This approach privileges the external observer in a classical realm distinct from the quantum realm of the object observed and the nature of the boundary between the quantum and classical realms remains unclear.

The Many worlds' interpretation addresses precisely this point by merging the microscopic and macroscopic worlds, thus making the observer an integral part of the quantum system. A universal wave function links macroscopic observers and microscopic objects as a part of a single quantum system, which would introduce a discontinuity in the wave-function collapse. Conversely, if we assume the continuous evolution of wave functions is not interrupted by the act of measurement. And if the Schrödinger equation holds good even for objects and observers alike with no elements of superposition banished from reality. Under these circumstances the wave function of an observer would, in effect, bifurcate at each interaction of the observer with a superposed object. The universal wave function would contain branches for every alternative making up the object's superposition. Each branch has its own copy of the observer, a copy that perceived one of those alternatives as the outcome (resulting in multiple universes). According to a fundamental mathematical property of the Schrödinger equation, once formed, the branches do not influence one another. Thus, each branch (universe) embarks on a different future, independently of the others.

The consistent histories is based on a consistency criterion that allows the history of a system to be described such that the probabilities for each history obey the rules of classical probability while being consistent with Schrodinger's equation. It turns out that none of these theories are completely satisfactory. At the end of the book, the author expresses hope that sometime in future, quantum physics will be able to distinguish the illusion and physical realty. This is farfetched because there is a growing consensus among many physicists that the answers to the problems in quantum reality may be found in string physics such as superstring theory or brane physics, and not through the unification of quantum physics with classical physics. Some physicists even believe that the unification of the two theories with respect to the gravitational force is inherently problematic if not impossible.

1. Quantum Reality: Beyond the New Physics
2. The New Quantum Universe (Revised and Updated Edition)