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What is parity

  1. Mar 27, 2006 #1
    Could you help me to get some sensible definition of parity? In my book they talk about having negative reversing coordinates and stuff. :frown:

    What does it physically mean to reverse coordinates? :bugeye:

    Any understandable definition of parity?

    thank you vr mch.
     
  2. jcsd
  3. Mar 28, 2006 #2
    A discrete symmetry operator that changes the sign of the momentum.

    [tex]Pa_{\mathbf{p}}P^{-1}=a_{-\mathbf{p}}[/tex]

    Here a is an anihilation operator (it works on any Hilbert space operator responsible for the creation/anihilation of four-momentum).

    Which is the same as flipping the coordiante axes, so that the positive spatial axes become the negative and visa versa.

    There are two other very important discrete symmetries: charge conjugation and time reversal.
     
    Last edited: Mar 28, 2006
  4. Mar 29, 2006 #3
    Parity is actually an inborn quality that is attatched with the particle when it is born, just like mass and charge. Well, now reversing the coordinates means a reflection across the origin. Now, u might ask wat does reflection across the origin mean? it is reversing the signs of ur coordinates. for eg ur particle is on (1,1,1). Reversing means (-1,-1,-1). Did u get that? Now consider ur particle as a Bohr wave. ok. So it must have some wave function defining its motion. Ok. if there is a sign change in the wave function when u reverse the space, it means it has odd parity. And if the sign doesnt change, it means it has even parity. Getting used to this term will require a lot of reading.
     
  5. Mar 31, 2006 #4
    thank you ram.

    Does it than violate "law" that laws of physics should be independent of reference frame? You are telling me that different reference frame will have different properties?
     
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