Quantum Physics for Beginners # 1

Until the 20th century, the only physics humankind was aware of was that which involved energy and time. The science that successfully describes these processes is called thermodynamics. This is based on the very reasonable idea that any activity in this Universe requires energy to be expended and takes time to complete. Alas this isn’t true. At the beginning of the 20th century Einstein completely revised the traditional thinking on time. Time had always been thought of as universal, one time for all; however Einstein showed that your time is different from mine. Indeed your time depends on the speed you’ve been travelling, the acceleration you’ve been subjected to, and the gravitational field you’ve been living in. But Einstein’s theory of relativity is incomplete; it provides a mathematically useful geometric analysis of time and space but by-passes the fundamental science completely.

Until the 20th century we thought that thermodynamics and relativity described everything there was to know about the Universe, or perhaps more accurately, the fabric of the Universe. Max Planck in 1900 had fired the first warning shot that showed that all wasn’t so cosy when he discovered that light can absorb and admit radiation only in energy bundles (later called quanta) whose size was proportional to the frequency of radiation. It ranks as one of the greatest discoveries in science but Planck hated his idea. He was obsessed with thermodynamics (particularly the second law), his problem was that for his quanta to work they had to temporarily break the second law (for reasons to be explained in later posts). Photographs show a miserable Planck at the time — yes, really miserable. The discovery won him a Noble Prize in 1918 but that didn’t cheer him up, I guess you can’t please everyone.

The wonderful (I use the term advisedly) thing is that thermodynamics and relativity are not the underlying truth of the Universe; they are just special cases of a more fundamental physics. That physics is called quantum physics. Quantum physics does away with the pesky inconvenience of time and energy, indeed any particle that finds itself in the quantum world will be everywhere simultaneously. Don’t laugh — life, including you, couldn’t exist if for significant periods the sub-atomic particles that you are made of don’t temporarily appear everywhere in the Universe simultaneously. You don’t have to take my word for this, the great Richard Feynman (Nobel Prize in 1965) spent a large chunk of his career demonstrating it.

Next article I’ll get down to specifics, and if you don’t agree with any of it or don’t understand it then please comment.