Why Take 'The Strange World of Quantum Mechanics'

Why would anyone want to take a course called "The Strange World of Quantum Mechanics"?

Just over 100 years ago, physicists exploring the newly discovered atom found that the atomic world of electrons and protons is not just smaller than our familiar world of trees, balls, and automobiles, it is also fundamentally different in character. Objects in the atomic world obey different rules from those obeyed by a tossed ball or an orbiting planet. These atomic rules are so different from the familiar rules of everyday physics, so counterintuitive and unexpected, that it took more than 25 years of intense research to uncover them.

But it is really only in the last 10 or 20 years that we have come to appreciate that the rules of the atomic world (now called "quantum mechanics") are not just different from the everyday rules (now called "classical mechanics"). The atomic rules are also far richer. The atomic rules provide for phenomena like particle interference and entanglement that are simply absent from the everyday world. Every phenomenon of classical mechanics is also present in quantum mechanics, but the quantum world provides for many additional phenomena. (These are the phenomena currently being exploited in the emerging field of quantum computing.)

Just as a flat map is a good approximation to a globe -- so long as one takes only short journeys; so classical mechanics is a good approximation to quantum mechanics -- so long as one investigates only objects larger than molecules.

Here's another analogy: Some films are in black-and-white and some are in color. It does not malign any black-and-white film to say that a color film has more possibilities, more richness. In fact, black-and-white films are simply one category of color films, because black and white are both colors. Anyone moving from the world of only black-and-white to the world of color is opening up the door to a new world -- a world ripe with new possibilities and new expression -- without closing the door to the old world.

This same flood of richness and freshness comes from entering the quantum world. It is a difficult world to enter, because we humans have no experience, no intuition, no expectations about this world. Even our language, invented by people living in the everyday world, has no words for the new quantal phenomena -- just as a language among a race of the color-blind would have no word for "red".

This course is not easy: it is like a color-blind student learning about color from a color-blind teacher. The course is just one long argument, building up the structure of a world that we can explore not through touch or through sight or through scent, but only through logic. Those willing to follow and to challenge the logic, to open their minds to a new world, will find themselves richly rewarded.