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What is the true significance of Quantum Information Theory?

  1. Feb 17, 2012 #1

    As I understand it, Quantum Information Theory is an attempt to apply the Classical Information Theory (i.e 0's and 1's) into the Quantum realm of superpositions.

    I recently came across a fascinating interpretation of QIT wherein it was described as possibly the law that effectively says that
    'information, once it has been generated can never be destroyed. So if ordered information is generated, then even if it leaks out of the system into the environment, it will still exist. The only thing that will change would be that the information would be harder to reassimilate into its original ordered state'

    For example- if a drop of ink is dropped into a container of water, the information stored inside that ink drop would still exist even in the diffused state. The information cannot be destroyed.

    Am I thinking correctly? And if I am, is the following statement correct-
    - Information once created, can never be destroyed.

    Shedding some light on this matter would be really helpful...also any metaphysical consequences of the above argument would be welcome!
  2. jcsd
  3. Feb 19, 2012 #2
    I too would really like to know the answer to this.

    I have just started reading "Vlatko Vedral - Decoding Reality; The Universe as Quantum Information" and he seems to be saying that the reason computers get hot is because the act of deleting information means some entropy has to be lost and this is released as heat...

    can this really be true ????
    i.e. once some information is created it is then in some way physical?

    see http://www.sciencedaily.com/releases/2011/06/110601134300.htm
    Last edited: Feb 19, 2012
  4. Feb 19, 2012 #3
    As far as I know, STORING information causes our computers to release heat- this is the direct consequence of the 2nd Law of Thermodynamics which basically states that the the overal entropy (randomness~chaos) of the unievrse continues to increase no matter what you do. So even if you try to reduce the entropy by creating ordered data...simultaneously as a direct result of this act, the universe will still increase its entropy i.e by generating heat. Look at it this way...you can memorize an entire book from cover to cover, that should effectively reduce the entropy cuz ur generating order inside ur head, but due to the second law , while u were memorizing the words, your brain was heating up, ur digestion was increasing, u might have started sweating etc. Hence the entropy always increases, even on the creation of order & thats why our computers have a fan at the back.
    The article that you reffered to...THAT was new to me! So thankyou for that!! But then again...it also states that if entropy is generated during deletion of data then that is a negligibly small number...~ millionth of a joule for the deletion of trillions of bits..

    But in the end this weird phenomenon did have something to do with Quantum information theory since entanglement appears to a big part of the process!
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