Wednesday, January 28, 2009

Factoids about Schrödinger's Cat

Weirdness is the name of the game for particles the size of an atom or smaller. Quantum particles exist in multiple states and positions at the same time. This can be hard to visualize sometimes, fortunately there's a couple of metaphors that can help out.

"Factoid" is one of the more curious words in the English language today. It was originally cooked up 1973 by author Norman Mailer while he was penning a biography of Marilyn Monroe as a word to describe "facts" that weren"t accurate. The suffix "-oid" means a "similarity, not necessarily exact, to something else," so by adding it to the word "fact," Mailer describes information that is accepted as true, especially by the media, but isn't

More to the point: In fact, a "factoid" isn't factual.

By cruel twist of fate, the use of "factoid" has been distorted to the point where its original meaning has been obscured. Over the years it's been misused (usually by the media ironically) to the point where if you look the definition of this troublesome word up in the dictionary today, the two definitions you are presented with are as follows:

1. A piece of unverified or inaccurate information
2. A brief, somewhat interesting fact.

Condensed down:

1. A piece of information that is not true.
2. A piece of information that is true.

The only way to tell which definition is relevant at any given time is by its context. Until the moment that the word is measured by putting it in a sentence, it means either and both of two polar opposite definitions.

Just like a quantum particle.

Until the moment a subatomic particle like a photon or electron is measured, it exists in every possible state at once. To really illustrate how weird this idea is, Erwin Schrödinger came up with a slightly macabre thought experiment now affectionately known as Schrödinger's Cat.

There is a box with a cat inside. Also inside is a vial of poison gas hooked up to a Geiger counter and an atom of an unstable element. When the atom decays and emits radiation, the Geiger counter registers it, releasing the gas, and kills the cat. The atom has a certain quantum mechanical probability of decaying at any given moment and until the moment it's measured, exists as both a decayed and complete atom. Unfortunately for the poor feline involved, this means that until the box is opened, the cat would exist in both a living and a dead state. This is obviously absurd.


The point of the thought experiment is not to actually develop an overly elaborate cat-killing device, or even that the feline in question would actually be both dead and alive, but to illustrate how really bizarre quantum particle behavior really is. Just like the word "factoid" which has multiple definitions at once until its context is determined, so too can subatomic particles exist in multiple states and positions until they're measured.
We've got our own section of daily factoids on our Physics Central homepage. Hopefully it's easy to quantify what kind of factoids they are. Should we change the name to avoid any confusion?

20 comments:

  1. The same can be said for "Peruse". It means, depending on which definition you prefer, to either glance over something quickly or thoroughly study it. Not sure how you can briefly deeply study something, but I'm sure science has the answer.

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  2. Also works for "table" as a verb. And "oversight" as a noun.

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  3. I guess that's why we needed "truthiness".

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  4. Factlet for true, factoid for false. (Both are etymological hybrids: fact- is Latin, -oid sort-of-Greek, and -let Teutonic.)

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  5. Also "drop."

    Engadget readers can never tell if a product has been canceled, or released (in the record industry sense).

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  6. Huh!

    Schrodinger's Cat is an Abyssinian!

    Who knew?

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  7. Sanction, both as a verb and as a noun.

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  8. Factoid(2) is actually a Factette.

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  9. The physical interpretation of the wave function as you're describing it has not been used since the 1950's. For more recent information about quantum physics look at the minimum principle and Richard Feynmann.

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  10. No one today uses the word "factoid" to mean a false putative fact, do they?

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  11. Keep it up and you'll gain quite a bit of notoriety.

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  12. Both meanings apply; when I pass on a factoid, like that there are 30,000 albinos in Tanzania or that 86 cents of every dollar of "foreign aid" never leaves the U.S., it's with the understanding that this kind of thing is a lot more likely to be a myth than a longer-than-factoid-length statement.

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  13. Join the petition--change the "factoids" on physicscentral to...

    Physics noodle OR Physics Qubit

    sincerely,

    a concerned citzen

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  14. I don't understand why "Schrodinger's Cat" is a paradox--isn't it obvious that you cannot measure/"observe" a protron with current known methods (ie. measure a subatomic light partical with another light partical) because doing so disturbs it and causes waveform collapse. In the scenario described, the cat is not in two states. Its either alive OR dead--not both. Its dead if the decay happens and alive if not. If the decay happens, if we wait long enough--it will be dead. End of story. Why is this thought experiment so hard to understand?

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  15. I agree with Nick. 'If you flip a coin and look at it, it could be either dead or alive.' OoooOooh.
    Unless you actually know the quatum physics behind it this is not interesting and would-be-philosophers take a basic concept way out of context.
    I realise this is nothing to do with your post, but gah. Nick knows what is going on.

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  16. first of all, we all know the cat kills himself because no cat is just gonna sit there when there is something else in his space to play with.

    It is so obvious Schrodinger made an ass out of us all with this "theory" which makes no sense. And he got a Nobel Prize for pulling the most legs in Scientific history.

    the bottom line, which is the explanation for ALL things is we do not know the outcome until we look.  schrodinger's cat is the state our minds are in. what WE are thinking.

    It is so obvious, it is confusing because no one gets why he even brought it up in the first place.

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    Replies
    1. A much simpler answer is that his equation works and his thought experiment is an interesting illustration of quantum mechanics.

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