Daily Archives: January 2, 2010

And so a new year has arrived and another chronological quantum has elapsed.

Can I use quantum that way? Yes, I can, drawing on its older but not obsolete sense simply of “discrete amount.” The word comes from the Latin meaning “how much” and has also been used to mean “something that has quantity,” “total amount or quantity,” and “individual share”; it has been circulating in these senses since the 16th century.

But we have Max Planck and Albert Einstein to thank for its most common current sense, which is “the smallest amount that can exist.” That is, if you take something, be it matter or time or electrical charge or whatnot, and cut it in half and in half and in half and so on, you will come to a point where it is impossible to cut any further. This amount that can’t be divided is a quantum.

Among the other things that have quanta are energy levels. The energy level of an electron can vary, but since it’s a very small thing and these energy levels are as a result very small, it can’t vary by less than a certain amount. Say there are levels 1 and 2: it can be at level 1 or level 2, but not at any level in between. So it jumps from one level to another – a quantum jump or, as it is now commonly called, a quantum leap.

A quantum leap, thus, in physics, is a very small change – the smallest possible change. In popular usage, on the other hand, quantum leap, with its space-age-sounding quantum and its leap that almost feels like the act of leaping, has come to mean a very big change. Naturally, there are plenty of people who will line up to tell you that this usage is wrong. Wrong, wrong, wrong! Quantum leaps are as small as small can be! Sheesh!

But there is actually nothing keeping quantum leap from describing something quite macroscopic. The essential characteristic of a quantum leap is that it is a change from one discrete state to another, with no intermediate possible – like flicking off a light switch that has no dimmer on it. The smallness of it in relation to subatomic particles is a simple entailment of this characteristic; if it can’t be subdivided, it must be very small. There are, however, things in life that are much larger state changes with no intermediates. You’re married or you’re not, for instance. Thus, something that is a huge change but that is unavoidably an abrupt change from one state to another could be said to be a quantum leap.

Admittedly, people who use quantum leap for very big things likely are not following this thought process; they’re probably thinking something more along the lines of “scientific! technical! space age! stars! space ships! warp engines! lllleeeeaaaap!”And they might use it for changes that in fact could have lesser degrees. Which would not be true to the source.

Quantum also shows up with words other than leap, to be sure. Some of its other close friends are mechanics, theory, physics, and computing. All of this gives it that far-out, space-agey feel that is exploited in its use in brand names. This is all the more so because while people generally know little about quantum mechanics, they do tend to know it’s pretty weird and that things happen in it that don’t really work the way we would think they should. There’s lots of uncertainty and improbability, and then there’s that thing about someone’s cat in a box (Schrödinger’s, to be precise) being simultaneously dead and alive until someone checks… On top of this, the q makes it feel questioning and quirky, and the um makes it feel formal or technical.

But, while it will always now be flavoured by its scientific connotations, it is still used in the older senses, sometimes even in popular entertainments. We can all take a quantum of solace in that.