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Homework Help: Question about photons

  1. Apr 7, 2005 #1
    Hello All,

    I have a question about photons. In A. Einstein ecuation (about Lorenzt transformation), there's a square root of c^2-v^2. My question is about what is the v represented: a vector? Only one direction vector? Only his module?

    best reggards.

    R.apaparioscios.
     
  2. jcsd
  3. Apr 7, 2005 #2
    Do you mean (1 - β^2)^1/2, where β = v/c? It's just the size of the velocity, so the modulus.
     
  4. Apr 7, 2005 #3
    Ok

    It's right. Is the modulus, but: could be a paravector???
     
  5. Apr 8, 2005 #4
    What's a paravector? :confused:
     
  6. Apr 8, 2005 #5
    Paravector

    Hello now,

    A paravector is a generalization of a vector, with a non-vectorial part and a vectorial part (like complex numbers have Real + Complex number). There are more generenalizations of vectors, like hypercomplex of hamilton, and the most general interesting now is Clifford Algebras and Geometric Algebra.

    Could say that a vector is a paravector without escalar part in this example.

    my best reggards.
     
  7. Apr 8, 2005 #6

    dextercioby

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    You'd need a new theory for that.For the Theory of Relativity developed over the last exactly 100 years,that "v" from [itex]\beta [/itex] or [itex] \gamma [/itex] is a scalar,namely [itex]\left|\vec{v}\right| [/itex]...That "v" has nothing to do with photons,of course...

    Daniel.
     
  8. Apr 8, 2005 #7
    the v is just an ordinary velocity-vector. It has three dimensions or equivalently it has three components, just like in the case of Lorentz transformations. That's all. The v² is the magnitude of this vector which is determined by calculating the scalar product of this vector with itself.

    The v is the velocity of one frame of reference to another...
    marlon
     
  9. Apr 9, 2005 #8
    Paravector

    Could be the velocity, a paravector or multivector, and this 'v' its module???
     
  10. Apr 9, 2005 #9

    dextercioby

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    It could iff u changed the whole theory.It could be pseudovector,the trace of a rank 658 tensor,etc...

    Daniel.
     
  11. Apr 9, 2005 #10
    Whole theory???

    Daniel,

    What whole theory?
     
  12. Apr 9, 2005 #11
    Maybe he means SR, I dunno.
     
  13. Apr 9, 2005 #12

    dextercioby

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    Yeah,change SR,you'll need to change GR as well.For the time being,they are successful theories and these theories address the velocity in the "gamma-factor" as the modulus of an ordinary 3-vector...

    Daniel.
     
  14. Apr 9, 2005 #13
  15. Apr 15, 2005 #14
    Meaning of SR and GR

    I'm sorry for my ignorance. What means SR and GR?
     
  16. Apr 15, 2005 #15

    dextercioby

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    Special Relativity and General Relativity.


    Daniel.
     
  17. Apr 15, 2005 #16
    Ok

    Dear Daniel,

    What I say is, what to unify SR an GR, we need to think the same way in both, and Geometrical Algebra provides a new tools to face it. If we take a multivector and apply a generalization of the Bertrand Russell circle, there are very interesting insights.

    But this is very confusing to me.

    Thanks another time.
     
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