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    I've spent the last few days watching videos about string theory and it seems pretty interesting. Then I decided to go onto LQG but can't seem to find any popular videos on youtube.

    Is String Theory more reliable and developed now? Are people more convinced and are putting more time towards it?

    Quote me please
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    (Original post by champ_mc99)
    I've spent the last few days watching videos about string theory and it seems pretty interesting. Then I decided to go onto LQG but can't seem to find any popular videos on youtube.

    Is String Theory more reliable and developed now? Are people more convinced and are putting more time towards it?

    Quote me please
    String theory is very ambitious and tries to explain alot with one underlying idea, meanwhile LQG is only a quantum theory of gravity.
    The main problem with LQG which is not apparent in string theory is that it violates Lorentz invariance. This causes quite a few problems with special relativity by selecting a kind of 'prefered' reference frame. This is not allowed in the theory of SR.
    String theory was not really in the spotlight until 1984, when super-symmetry was incorporated and as a result it becoming a candidate for the 'theory of everything'. The unifying theory, that brings together all 4 forces into a nice, neat, nicely packaged set.
    LQG cannot even dream of this It is only (at the moment) a theory for gravity and cannot be extended to incorporate other forces under the same 'framework'.

    To address the 'more reliable' bit, ST has derived the Beckenstien Hawking formula for black hole entropy for extremal black holes. LQG apparently has but has to assume an artificial value for the Barbero-Immirzi parameter.

    As a result string theory has become the preferred theory on quantum gravity AFAIK.

    This is probably why you dont see much on it xD
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    (Original post by The-Spartan)
    String theory is very ambitious and tries to explain alot with one underlying idea, meanwhile LQG is only a quantum theory of gravity.
    The main problem with LQG which is not apparent in string theory is that it violates Lorentz invariance. This causes quite a few problems with special relativity by selecting a kind of 'prefered' reference frame. This is not allowed in the theory of SR.
    String theory was not really in the spotlight until 1984, when super-symmetry was incorporated and as a result it becoming a candidate for the 'theory of everything'. The unifying theory, that brings together all 4 forces into a nice, neat, nicely packaged set.
    LQG cannot even dream of this It is only (at the moment) a theory for gravity and cannot be extended to incorporate other forces under the same 'framework'.

    To address the 'more reliable' bit, ST has derived the Backenstien Hawking formula for black hole entropy for extremal black holes. LQG apparently has but has to assume an artificial value for the Barbero-Immirzi parameter.

    As a result string theory has become the preferred theory on quantum gravity AFAIK.

    This is probably why you dont see much on it xD
    Cheers mate. I understood the stuff not in bold. I'll look it up.
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    (Original post by champ_mc99)
    Cheers mate. I understood the stuff not in bold. I'll look it up.
    In summary:
    Lorentz invariance is basically the idea that a Lorentz scaler (a value with only a magnitude) remains unchanged through a Lorentz transformation. Or even more basically the idea that every reference frame is considered of equal preference for SR.

    Beckenstein hawking entropy is basically the amount of entropy (chaos in the system) that must be assigned to a black hole for it to agree with the laws of thermodynamics for observers external to the black hole.

    The Barbero-Immirizi parameter is a measurement of the size of the quanta of area in planck units. (Since LQG quantises everything to have a definite size). This was kind of artificially altered to agree with the above.
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    (Original post by The-Spartan)
    In summary:
    Lorentz invariance is basically the idea that a Lorentz scaler (a value with only a magnitude) remains unchanged through a Lorentz transformation. Or even more basically the idea that every reference frame is considered of equal preference for SR.

    Beckenstein hawking entropy is basically the amount of entropy (chaos in the system) that must be assigned to a black hole for it to agree with the laws of thermodynamics for observers external to the black hole.

    The Barbero-Immirizi parameter is a measurement of the size of the quanta of area in planck units. (Since LQG quantises everything to have a definite size). This was kind of artificially altered to agree with the above.
    Cheers again! Which one do you lean towards?
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    (Original post by champ_mc99)
    Cheers again! Which one do you lean towards?
    No problem!! Personally looking at the maths, string theory wins it for me. LQG is just too interesting a concept to put down so soon though sooo i kind of suppose deep down i root for it sometimes
    m-branes are another cool thing to check out if youre interested!!
 
 
 
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