NERD ALERT: book review of QUANTUM by Manjit Kumar

I just finished an awesome book - QUANTUM: Einstein, Bohr and the Great Debate About the Nature of Reality by Manjit Kumar.

The author provides a summary of the discoveries and scientific advancements that led to quantum mechanics (QM, a sub-field of physics). Brief biographies are artfully entwined into the achievements made by physicists in the 1800's to 1900's; extensive references, personality descriptions, quotations from personal letters, and a sense of humor provide an insight into these scientists and a history of modern physics that I never got from textbooks. The story is centered in Europe, mostly Bern, Copenhagen and Gottingen. The effects of the two world wars on theoretical physics and the scientists is also discussed, which I found very interesting. I have no talent for retaining historical information and I've already forgotten the many amazing, thought provoking, funny and quote-able parts of this book, so I'll have to skim through again and highlight so these things will be easier to find when I want to look back. Hopefully someone else will read it soon so I can discuss it.

Some random facts:

It seems that most of the notable physicists in that time made their greatest discoveries in their early to mid twenties. Sometimes, their doctoral dissertations were ground breaking, and they were made professors by their late twenties. Ernest Rutherford had 11 of his students and close collaborators win Nobel Prizes. Einstein had written two letters to President Roosevelt encouraging research on the atomic bomb.

The book first lays the foundation for understanding how QM as a field developed and came about, which takes most of the book, and later goes into the details of the fundamental disagreements between Neils Bohr and Albert Einstein about the theory as a whole and its implications.

I'll outline the basic points of view here:

Neils Bohr - "There is no quantum reality beyond what is revealed by an act of measurement or observation. Hence it is meaningless to say, for example, that an electron exists somewhere independent of an actual observation." Basically, for something to exist, there needs to be someone/something observing that other something. He also claimed that QM was a complete theory.

Albert Einstein - He thought that QM was not a complete theory. He did not believe in an observer-dependent reality, but believed that something would exist regardless if there was no one to observe or measure it.

"Einstein versus Bohr had little to do with the equations and numbers generated by the mathematics of quantum mechanics. What does quantum mechanics mean? What does it say about the nature of reality? It was their answers to these types of questions that separated the two men. Einstein never put forward an interpretation of his own, because he was not trying to shape his philosophy to fit a physical theory. Instead he used his belief in an observer-independent reality to asses quantum mechanics and found the theory wanting."