Someone in an e-mail list devoted to discussions of the Afrikaans language has raised this rather intersting question: If one definition of "quantum" is "The smallest amount of a physical quantity that can exist independently", how did "quantum leap" come to mean "an abrupt change, sudden increase, or dramatic advance" (as defined in Merriam-Webster Collegiate Dictionary, which dates the expression’s origin to 1956.
In case anyone wonders why an English expression came to be queried in a discussion of another language, the original questioner was asking somewhat indignantly why Afrikaans has slavishly followed this apparent anomaly by adopting a literal translation of the expression.
From the little I’ve read about quantum physics, it’s weird… As someone (probably mis)quoted Niels Bohr as saying, "If you can think about this without your head spinning, then you haven’t understood it."
In the quantum world, if a particle can be in more than one state, then it is in all those possible states at once until an observation is made that determines what state it is in.
The most famous example of this is the Schroedinger’s Cat ‘thought experiment’ (i.e. just think about it), in which there is: a box containing a cat; an atom that has a 50% chance of decaying within one hour; and equipment that will release poison gas if the atom decays. An experimenter who looks in the box after an hour will find the atom either decayed or undecayed and the cat either dead or alive. Simple.
Now for the weird bit. According to quantum mechanics, until the lid is lifted the atom and the cat exist in two ‘superposed’ states: the atom is both decayed and undecayed, and the cat is both dead and alive. Of course, this is completely counterintuitive in our macroscopic world, but it seems there is now experimental evidence to prove it (see this Scientific American article).
So I assume a quantum leap is a jump from one quantum state to another. (I tried to use Google to confirm this, but got a lot of pages devoted to some TV show…) Why in common parlance the new state is always more advanced, I’m not sure - Progress, I suppose.
Ed
Superposed - head spinning AND I don’t understand it!
One of the revolutionary concepts introduced by quantum theory was the idea that energy is released or absorbed in discrete quanta, or specific amounts, and not in a continuous fashion. This would be analogous to having a car that travels only at speeds of 5, 10, 15, 20, etc., miles per hour, but cannot travel at speeds in between those, such as 6, 7, or 18-1/2 miles per hour. Such a car vould not accelerate smoothly from 0 to 60 miles per hour, but would move in instantaneous jumps from 0 to 5 to 10 to 15 and so on up to 60. These would be quantum jumps. A quantum leap is therefore an abrupt change rather than a smooth, gradual change. A quantum leap can be in either direction. An electron moves to a higher orbit when it absorbs energy, and releases energy (such as light) when it moves back to a lower orbit.
One might say that the atomic and hydrogen bombs represented quantum leaps in munitions technolgy. (Pun intended!)
Here are the relevent definitions with emphasis added:
1. A quantity or amount.
2. A specified portion.
3. Something that can be counted or measured.
4. Physics
a. The smallest amount of a physical quantity that can exist independently, especially a discrete quantity of electromagnetic radiation.
b.This amount of energy regarded as a unit.
adj.
Relating to or based upon quantum mechanics.
[Latin, from neuter of quantus, how great ; see quantity.]
quantum jump
n.
1. Abrupt change from one energy level to another, especially such a change in the orbit of an electron with the loss or gain of a quantum of energy.
2. A quantum leap.
quantum leap
n. An abrupt change or step, especially in method, information, or knowledge: "War was going to take a quantum leap; it would never be the same" (Garry Wills).
One interesting feature of physics is the simultaneous acceptance of light as being both of continuous waves (analog) and discrete particles (digital) - in some situations, the wave model is more useful in predicting the behavior of light, and in others, particles provides a better explanation. So instead of having to choose only one or the other, scientists generally just split the difference and use the whichever fits the data-of-the-day on Monday and the opposite on Tuesday. Isn’t that convenient?
instead of having to choose only one or the other, scientists generally just split the difference
Perhaps they do that nowadays because they all work in committees, in which concensus is king. Back in the good old days, a lone loopy scientist experimented until truth was revealed (or not) and bugger the politics. Just a theory.
Quantum physics? Who gives a fig, Newton?
As for adonis, who gives a rat’s backside if it’s 11.59 or 12.01? It’s all according to how we set our clocks in the first place.
In 1925, our understanding of light seemed to have come to an impasse. Particle theory could explain reflection and refraction, and recent experiments in radiation (such as the radiation from hot bodies and the Compton experiment with X-rays). And wave theory could explain the interference and polarization of light which particle theory could not. Thus simple and sophisticated experiments both indicated that light could be a particle sometimes and a wave at others.
Albert Einstein (1924) expressed the dilemma:
There are therefore now two theories of light, both indispensable, and - as one must admit today in spite of twenty years of tremendous effort on the part of theoretical physicists - without any logical connections.
The dilemma prompted Neils Bohr (1928) to offer his ‘complementarity principle’: that particle theory and wave theory were equally valid. Scientists should simply chose whichever theory worked better in solving their problem. While it got physics out of its immediate hole, coming from someone as important in modern physics as Bohr, it gained a dominance in physics teaching probably never intended.
A man with a (12 hour) watch that has stopped has an instrument that shows the correct time twice a day, which is more than can be said for the chap with a watch that works….
Getting back to the original question, there is a good reason why moving on the quantum scale (very little) can describe something big (a quantum leap). The important point is not that a tiny something moves just a little bit, but that it doesn’t go through the intervening somewheres. People use quantum leap not so much to mean a big leap, but a sudden (seemingly instantaneous) change. Getting from Thursday to Saturday isn’t a big thing, but doing it without having a Friday is a big thing.
How nice that this thread popped up again. I’ve been reading a little about qubits. Imagine tossing a penny. It’s spinning in the air. It is heads and tails at the same time. If I’m understanding correctly (for once), a qubit is can be regarded as being a binary 1 and 0 at the same time. Quantum computing will, I suppose, one day be as common as fish-and-chips. Some say it will speed up processing exponentially. Hm. I like the word, though. Qubit. Nice of them to leave the U in there, too.
[quote author=chmism link=board=etymology;num=1057910829;start=0#13 date=10/09/03 at 15:16:35][center]...[/center] The important point is not that a tiny something moves just a little bit, but that it doesn’t go through the intervening somewheres. ...
Or rather that, when we get down to the really small, there are no «intervening somewheres» ; i e, our universe is discrete in nature, like a child’s puzzle before the dots have been connected, rather than being continuous. Who would have guessed ?...
