Quantum Physics

Currently i am reading : The Ghost in the Atom

We live in an awkward time. Our understanding of the universe is based on two theoretical models, quantum theory at the atomic scale and relativistic theory at the astronomical scale. Despite valiant efforts, physicists have been unable to unify these two highly successful theories.

Quantum theory itself is based "on a profound and disturbing paradox that has led some physicists to declare that the theory is ultimately meaningless." And yet no experiment has contradicted the predictions of quantum theory. Physicists agree that quantum theory "correctly describes the world to a level of precision and detail unprecedented in science". The problem is philosophical, not technical.

I highly recommend "The Ghost in the Atom" as an excellent starting point for exploring the fascinating implications of quantum theory. P. C. W. Davies (physicist) and J. R. Brown (BBC producer) offer us an intelligent examination of the conflicting and controversial interpretations of this fundamental theory.

"The Ghost in the Atom" begins with a brief exposition (about 40 pages), titled "The Strange World of the Quantum", that summarizes quantum theory and introduces the interpretation problem. A remarkable set of interviews follow: eight noted physicists describe with enthusiasm, even passion, the bizarre implications of quantum theory as they see it.

Alain Aspect, a French experimental physicist, describes his 1982 experiment that challenged our view of reality by apparently confirming that non-locality is an attribute of our universe.

John Bell, a theoretical physicist at CERN, is known for his Bell's Theorem that provided the basis for Aspect's experiment. He discusses whether free will might be an illusion, suggests that we revisit Einstein's theory of relativity, and states that he is "quite convinced that quantum theory is only a temporary expedient".

John Wheeler, Director of the Center for Theoretical Physics at UT Austin, largely agrees with the conventional Bohr interpretation (also called the Copenhagan interpretation) and argues the importance of the conscious observer in the quantum measurement process.

Rudolp Peierls, who formerly held the Wykeham Chair of Physics at Oxford, objects to the term "Copenhagan interpretation", as it suggests that there is more than one acceptable interpretation. He considers other interpretations to be largely speculation.

David Deutsch, Research Fellow in Astrophysics at both Oxford and UT Austin, argues strongly for the many-universes interpretation. He is a proponent for objective reality.

John Taylor, Professor of Mathematics at Kings College, London, argues for the ensemble interpretation (or statistical interpretation). By abandoning any attempt to describe individual systems, he contends that there is no need to associate the collapse of the wave function with the presence of a conscious observer during the measurement process.

The final two physicists, David Bohm and Basil Hiley, both argue that a "hidden variable" interpretation involving a "quantum potential" can accommodate Aspect's non-locality and maintain objective reality.

"The Ghost in the Atom" is quite exceptional and I easily give it five stars. The quantum theory overview alone, as others have pointed out, is worth the price of the book. The interviews are fascinating.

What should you read next? I highly recommend another exceptional book published by Cambridge University Press, "Quantum Physics: Illusion or Reality?" by Alastair Rae. It is more difficult, but does not require mathematics. 

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