Are Lx, Ly, Lz (the components of Angular Momentum)independent to each other?

  • Level: Graduate 
  • Thread starter Thread starter yicong2011
  • Start date Start date
  • Tags Tags
    Angular Components
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
2 replies · 5K views
yicong2011
Messages
75
Reaction score
0
In Classical Mechanics, are the three components of Angular Momentum L:

Lx, Ly, Lz

independent to each other?

It seems that there is an identity in Classical Mechanics (Sorry, I can hardly remember where I saw it):

[Li, Lj] = εijk Lk.

Note: [] is Poisson Bracket, εijk is Levi-Civita Tensor

If the identity is true, then the three components of Angular Momentum are not independent to each other.
 
Physics news on Phys.org
Angular momenta are independent of each other. Take the obvious case of planar motion in the xy-plane. Then Lx and Ly are zero, and Lz can be anything.
 
yicong, Of course you are misinterpreting the meaning of the Poisson bracket. Note for example in three dimensions with Cartesian coordinates xi, the Poisson bracket relationship [xi, xj] = 0 for i and j not equal.