Review of "Einstein's Dice and Schrödinger's Cat: How Two Minds Battled Quantum Randomness to Create a Unified Theory of Physics" by Paul Halpern

Two of the most important developments in theoretical physics occurred in the early 20th century. Albert Einstein formulated the theory of general relativity and Erwin Schrödinger, Max Planck, Louie de Broglie and others devised quantum physics. In this book, physics professor Paul Halpern discusses the origin and evolution of these groundbreaking ideas.....and Einstein and Schrödinger's lifelong quest to find a 'unified theory of everything.'


Albert Einstein


Erwin Schrödinger


Max Planck


Louie de Broglie

Theoretical physics encompasses difficult ideas described by dense mathematical formulas. Halpern, however, devises clever analogies to help the reader understand the big picture. For example, curvature in the universe is compared to a saddle or - for snack lovers - a potato chip.



And quanta (energy packets that are multiples of a very small quantity) are correlated with coins of different denominations (penny, nickel, dime, etc.).



Einstein is considered one of the greatest scientists who ever lived but - as a young person - was a rather indifferent student. The budding genius did love geometry, though, and this may have led to his developing the theory of general relativity.

The geometry Einstein studied as a boy (and what we learn in middle school) is called Euclidean geometry. This is geometry on a flat surface. In the real universe, though, things aren't flat, and a different kind of geometry - called Non-Euclidean geometry - is needed. Non-Euclidean geometry has precepts that differ from what we're used to. For instance, triangles can have three right angles and parallel lines can meet.

Einstein's theory of general relativity is based on Non-Euclidean geometry and spacetime.





Spacetime is the concept that the three-dimensional geometry of the universe (the location of things on an xyz-axis) and the time dimension (when events occur) are not separate things. They form a single unit.

In very simple terms, the theory of general relativity says:
- The presence of matter in the universe alters the geometry of spacetime - that is, it curves spacetime.
- Gravity is a manifestation of the curvature of spacetime.
- Objects that 'fall' because of gravity are following straight line paths in a curved spacetime.


Gravity is illustrated in this diagram. The grid is spacetime, the sphere is matter (let's say the Earth).....and gravity diverts the trajectory of the object (let's say the moon).


Instructor demonstrating gravity

In the early 1900s scientists discovered that sub-atomic particles (such as electrons and photons) can behave as both particles and waves. Schrödinger derived the wave equation, which is a basic tenet of quantum mechanics. Schrödinger's wave equation is used to determine information about a particle - such as its position, mass, velocity and energy - at every moment in time.



So far so good. Except that two other renowned physicists, Niels Bohr and Werner Heisenberg, took quantum mechanics a step further.


Neils Bohr


Werner Heisenberg

They formulated the uncertainty principle, which states that you can't know dual properties of a particle - like its position and momentum - at the same instant. If you measure the position of a particle, you change it's momentum.....and vice versa. So the more precisely you know one quantity, the less precisely you know the other. Therefore, you have to rely on probabilities.



Even odder (to regular people) is the Copenhagen interpretation of quantum mechanics. This states that particles DON'T HAVE definite properties until they're measured. In other words, a particle is 'smeared out' - or has a range of probabilities - until it's measured. At the moment of measurement, the particle acquires definitive properties.

Both Einstein and Schrödinger rejected this probability jibber jabber. They were sure the universe is deterministic, that events have causes, and that everything is predictable. This led Einstein to say "God does not play dice with the universe" and Schrödinger to devise "Schrödinger's cat" thought experiment - in which a cat in a sealed box is both alive and dead simultaneously. (You'll have to look it up.)



Because of their reservations, Einstein and Schrödinger tried to disprove the Copenhagen interpretation for decades, with no success. (That's probably because - according to experimental evidence - it's true.)

Both Einstein and Schrödinger also spent a large part of their lives trying to combine the general theory of relativity (the physics of large objects) and quantum mechanics (the physics of small objects) into a theory of quantum gravity (a unified theory of everything).

Einstein and Schrödinger were great friends - and had a friendly rivalry about their efforts - until 1947. That year Schrödinger thought he'd succeeded in unifying the theories and made a big announcement to the press, more or less thumbing his nose at Einstein. As it turned out, Schrödinger's equation was wrong......and Einstein didn't speak to him for three years.



Despite the efforts of many scientists, there still isn't a unified theory of everything.

Halpern doesn't shirk discussions of complex physics, and these sections can be difficult for the layperson to understand. However, the author also includes information about the personal lives of Einstein and Schrödinger, and these segments read like mini-biographies. Halpern writes about the scientists' young years, schooling, jobs, finances, children, escape from Germany and Austria before WWII, many contributions to science, Nobel Prizes, interest in philosophy (Einstein read Spinoza and Schrödinger leaned toward Schopenhauer and Eastern mysticism), and more.

Halpern also mentions some gossipy facts like: Einstein didn't like to get his hair cut, didn't wear socks, and - after divorcing his first wife - married his cousin.....to whom he wasn't faithful.


Einstein and his second wife Elsa

And Schrödinger had an open marriage. He often vacationed with a lady friend, and sometimes lived with his wife AND one or two girlfriends (some of whom had husbands).


Schrodinger and his wife Annemarie

Also, after Einstein died, the pathologist stole his brain, preserved it, and cut it up for scientific study.

Halpern emphasizes that great minds don't often make their major discoveries alone. Einstein and Schrödinger collaborated with other physicists and mathematicians - both in person and via mail. In later life Einstein had a routine: he would have breakfast with his colleagues and assistants, then stroll to his office with them - all the time having extensive discussions about physics. (Think of 'The Big Bang Theory' television show without the jokes.) Einstein also attended conferences and exchanged letters with other scientists.....as did Schrödinger. Thus, great leaps of knowledge are usually collaborative efforts - though 'celebrity scientists' often get the most credit.

I enjoyed the book (though some of it is tough going) and appreciated the insights into the advances in physics. I'd recommend the book to readers interested in the subject. 

Rating: 3.5 stars