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Thread: Does self-torque of light threaten QM completeness?

  1. #1
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    Does self-torque of light threaten QM completeness?


  2. #2
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    is there a question here?
    please refrain from posting naked links, you should at least give some explanation of what you are linking to.
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  3. #3
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    Dynamic OAM

    Here is another link with a useful video that describes this new property of light:

    https://phys.org/news/2019-06-property.html

    QM has been around for over 90 years and has been considered complete. So a need for a new quantum property would challenge internal consistency. Usually a new property, however surprising, can be expressed as a sum from the complete set rather than invoking a new quantum number and this may be the case here. Often predictions occur years in advance of experimental verification. So it seems a bit odd that from a closed set of properties that this prediction was not made some time ago. The distinction between static and dynamic OAM (optical orbital angular momentum) brings with it the quantization of dynamic OAM. So the question is whether the quantization is a sum of other known quantum properties or is a new quantum property needed for dynamic OAM.

  4. #4
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    Quote Originally Posted by borman View Post
    Dynamic OAM

    Here is another link with a useful video that describes this new property of light:

    https://phys.org/news/2019-06-property.html

    QM has been around for over 90 years and has been considered complete. So a need for a new quantum property would challenge internal consistency. Usually a new property, however surprising, can be expressed as a sum from the complete set rather than invoking a new quantum number and this may be the case here. Often predictions occur years in advance of experimental verification. So it seems a bit odd that from a closed set of properties that this prediction was not made some time ago. The distinction between static and dynamic OAM (optical orbital angular momentum) brings with it the quantization of dynamic OAM. So the question is whether the quantization is a sum of other known quantum properties or is a new quantum property needed for dynamic OAM.
    There is no mention of a new quantum property, internal consistency, new quantum number, etc. in the article, borman. So the answer to your question is no, this discovery does not threaten QM completeness. In 20/20 hindsight we could have realized back in 1992 that optical orbital angular momentum means that a temporal component to the OAM produces self-torque in light beams.

    Orbital angular momentum of light has the angular momentum l number. I suspect that in dynamic OAM, this varies along the beam.

  5. #5
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    Quote Originally Posted by borman View Post
    Dynamic OAM

    Here is another link with a useful video that describes this new property of light:

    https://phys.org/news/2019-06-property.html

    QM has been around for over 90 years and has been considered complete. So a need for a new quantum property would challenge internal consistency. Usually a new property, however surprising, can be expressed as a sum from the complete set rather than invoking a new quantum number and this may be the case here. Often predictions occur years in advance of experimental verification. So it seems a bit odd that from a closed set of properties that this prediction was not made some time ago. The distinction between static and dynamic OAM (optical orbital angular momentum) brings with it the quantization of dynamic OAM. So the question is whether the quantization is a sum of other known quantum properties or is a new quantum property needed for dynamic OAM.
    Dynamic OAM is the outcome of interactions between two states with different static OAMs and a phase difference. It's not a new quantum number or property. And even if it were I'd challenge both your claim that QM is considered complete and that a new property would challenge internal consistency. After all spin was added years after the basics of QM were worked out without anything breaking.

    I don't see it as that different from the previous work combining two beams with difference polarisations or frequencies - this is just another inventive step in producing light beams with interesting properties.

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