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Thread: Does Quantum Physics destroy information?

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    Does Quantum Physics destroy information?

    OK, I’ve read something that perplexes me.

    Information isn’t destroyed in classical physics because it just changes form. If you burn a letter, the information in it is still encoded in the wisps of smoke and other residue of the letter. However the atoms that encode the information are subject to quantum mechanics and as a result may change subtly over time due to minor quantum fluctuations, or even due to quantum fluctuations of the vacuum.

    To what extent would this destroy the information over time and make it unrecoverable by even the most powerful computations? It would seem to me that over many years, the unpredictability of quantum mechanics would create instances where the history of a particle would be impossible to recreate, and thus the information would be lost forever.

    E.g. a letter burned back in Julius Caesar's day would have at least some of its particles jostled in such a way that the letter could not be resurrected. Or maybe it would take a million years, but eventually it is gone.

    Thoughts?

    SLD

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    I understand. My usual response is to say you are mixing metaphysics with science. There is no strict definition for the term information.

    I look at things through causality, chins of cause and effect. The probabilistic nature of QM does not violate causality. Aystem goes from one stae to the enxt. The signifigance and meaning you attach to stes is arbitry, at least from my point of view.

    In simple Morse Code radio the transmitter is either on or off. We attach meaning as characters assigned to sequences of the pulses.

    QM is a set of predictive models. For me that is where it ends and philosophy begins.

    I used to read Scientific American every month. Back in the 90s a cover proclaimed the universe is information. Still have not figured out exactly what that means.

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    Information can be (strictly) defined as the opposite of entropy.

    As entropy always increases in a closed system, so information always decreases.

    No quantum theory required.

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    QM is a set of models. QM sows not 'do' anything.

    The SI definition for entropy os Joules/T on kelvins.

    There is no definition for information. Same with the terms order and disorder.


    In his book on Information Theory Shannon adopted entropy from thermodynamics to describe what hapens when coded signals representing text data losing definition over time and distance.

    As telegraph pulses propagate down wires they dimish eventualy getting lost in noise. Information entropy.

    Keep adding length to an Ethernet cable and eventually the digital signals will lose definition and disappear into noise. Information entropy. Like a refrigerator, digital repeaters are 'entropy reversers'.

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    Quote Originally Posted by steve_bank View Post
    There is no definition for information.
    It takes an impressive amount of pig-headed stupidity to repeat this baseless and ignorant claim immediately in response to a post that gives a definition for information.

    You don't have to like the definition, but you have to be crazy to claim that it doesn't exist when it's right there in front of you.

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    Quote Originally Posted by bilby View Post
    Quote Originally Posted by steve_bank View Post
    There is no definition for information.
    It takes an impressive amount of pig-headed stupidity to repeat this baseless and ignorant claim immediately in response to a post that gives a definition for information.

    You don't have to like the definition, but you have to be crazy to claim that it doesn't exist when it's right there in front of you.
    I do not have one. Please provide an explicit definition that defines information and how QM can destroy it.

    I gave an example of how in one field information has a specific quantifiable definition. It goes directly to the OP. Define information in context of the OP. I doubt it can be done. You can probably coble something together from scfi....


    As to entropy, again general terms over science. When you can discuss given steam at a given volume, temperature, and pressure what the entropy, ds, is during a heat transfer process. For a given state of steam how much energy can be extracted converting the steam to work? When you grasp that we can begin a conversation on entropy and the iformation and QM.

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    Quote Originally Posted by steve_bank View Post
    Quote Originally Posted by bilby View Post
    Quote Originally Posted by steve_bank View Post
    There is no definition for information.
    It takes an impressive amount of pig-headed stupidity to repeat this baseless and ignorant claim immediately in response to a post that gives a definition for information.

    You don't have to like the definition, but you have to be crazy to claim that it doesn't exist when it's right there in front of you.
    I do not have one. Please provide an explicit definition that defines information
    Information is the opposite of entropy.

    If the entropy of a system is S, the information content is -S.
    and how QM can destroy it.
    I haven't made any claims about QM destroying information, so I don't need to explain how it might or might not do so.

    Indeed, I specifically said "No quantum theory required".

    As your first paragraph has been shown to be nonsensical, I see no value in even addressing the rest of your claims. At least until we resolve the question of whether there is a definition of information.

    Which, as both you and I have given definitions, is evidently true.

    If you can't bring yourself to accept something so blatantly obvious, why would anyone think you had something useful to contribute?
    I gave an example of how in one field information has a specific quantifiable definition.
    And you then immediately contradicted yourself and declared that it has no definition.

    You should probably try not to do that if you don't want people to think you are crazy.

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    Quote Originally Posted by bilby View Post
    Quote Originally Posted by steve_bank View Post

    I do not have one. Please provide an explicit definition that defines information
    Information is the opposite of entropy.

    If the entropy of a system is S, the information content is -S.
    and how QM can destroy it.
    I haven't made any claims about QM destroying information, so I don't need to explain how it might or might not do so.

    Indeed, I specifically said "No quantum theory required".

    As your first paragraph has been shown to be nonsensical, I see no value in even addressing the rest of your claims. At least until we resolve the question of whether there is a definition of information.

    Which, as both you and I have given definitions, is evidently true.

    If you can't bring yourself to accept something so blatantly obvious, why would anyone think you had something useful to contribute?
    I gave an example of how in one field information has a specific quantifiable definition.
    And you then immediately contradicted yourself and declared that it has no definition.

    You should probably try not to do that if you don't want people to think you are crazy.
    You said information has an explicit definition.

    Let's hear the definition.

    Information can be (strictly) defined as the opposite of entropy. is gibberish. Entropy is a number, and strictly speaking it is a change of state not an absolute value. Order and disorder as used relative to entropy are subjective philosophical views. How does enthalpy enter into your definition? Entropy is running down, enthalpy is running up. The two terms are linked in a system.

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    Quote Originally Posted by steve_bank View Post
    Quote Originally Posted by bilby View Post
    Information is the opposite of entropy.

    If the entropy of a system is S, the information content is -S.

    I haven't made any claims about QM destroying information, so I don't need to explain how it might or might not do so.

    Indeed, I specifically said "No quantum theory required".

    As your first paragraph has been shown to be nonsensical, I see no value in even addressing the rest of your claims. At least until we resolve the question of whether there is a definition of information.

    Which, as both you and I have given definitions, is evidently true.

    If you can't bring yourself to accept something so blatantly obvious, why would anyone think you had something useful to contribute?
    I gave an example of how in one field information has a specific quantifiable definition.
    And you then immediately contradicted yourself and declared that it has no definition.

    You should probably try not to do that if you don't want people to think you are crazy.
    You said information has an explicit definition.

    Let's hear the definition.

    Information can be (strictly) defined as the opposite of entropy. is gibberish. Entropy is a number, and strictly speaking it is a change of state not an absolute value. Order and disorder as used relative to entropy are subjective philosophical views. How does enthalpy enter into your definition? Entropy is running down, enthalpy is running up. The two terms are linked in a system.
    What the fuck is wrong with you?

    Information is the opposite of entropy.

    Hello? HELLO?? Is this thing on?

    It's a definition. It's a strict definition. Indeed it cannot by definition be less strict than the definition of entropy.

    Wherever you discuss or refer to entropy, you can multiply by minus one, and call it 'information'. That's the definition.

    The negation of something that is strictly defined is by default also defined, via multiplication by -1.

    This is really basic stuff; Even an engineer should be able to grasp it.

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    I feel like a small yelping excited Chihuahua dog is trying to hump my leg.

    If you say information is the opposite of entropy without being able to describe what that means in physical reality, I'll take your word for it.Good is defined as the opposite of evil, but what does it mean to be good? No matter all I need to doo is define one term as the opposite of the other.

    That is called circular reasoning. What is good? The opposite of evil. But what then is evil? Why the opposite of good obviously. The word information is contextual for it to have meaning. There was a thread debating what information and knowledge is. To say information as a system is the opposite of entropy from thermodynamics you must articulate the system characteristics of information as you are seeing it and how it exhibits entropy.

    This is what Shannon did in digital communications.

    Entropy applies to systems and energy processing. What is the energy processing within information as you are using it? Simple question.

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