Understanding Parity: What Does Reversing Coordinates Mean?

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Discussion Overview

The discussion centers around the concept of parity in physics, specifically what it means to reverse coordinates and how this relates to the properties of particles. Participants explore definitions, implications, and the physical meaning of parity in various contexts.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant seeks a clear definition of parity and questions the physical meaning of reversing coordinates.
  • Another participant describes parity as a discrete symmetry operator that changes the sign of momentum, equating it to flipping coordinate axes.
  • A different viewpoint suggests that parity is an intrinsic property of particles, likening it to mass and charge, and explains that reversing coordinates involves reflecting across the origin.
  • This participant also introduces the concept of wave functions and how sign changes in these functions relate to odd and even parity.
  • One participant questions whether the concept of parity implies that different reference frames have different properties, suggesting a potential conflict with the idea that physical laws should be independent of reference frames.

Areas of Agreement / Disagreement

Participants express differing views on the nature of parity and its implications for physical laws, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Some definitions and interpretations of parity may depend on specific contexts or assumptions that are not fully articulated in the discussion.

sneez
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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.
 
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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:
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 doesn't change, it means it has even parity. Getting used to this term will require a lot of reading.
 
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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