1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Question about statement of Noether's theorem

  1. Jul 30, 2012 #1
    In a lecture on Classical Mechanics by Susskind, he says that for Noether's theorem to hold, we have to have a differential transformation of the coordinates which does not depend on time explicitly ie from [itex]\vec{q}\rightarrow \vec{q}'(\varepsilon,\vec{q})[/itex], where s is some parameter. I don't see why it's necessary that the transformation doesn't contain a time term -- as far as I can tell, his proof didn't require that assumption, but perhaps it crept in somewhere.

    Here's a link to the lecture: http://www.youtube.com/watch?v=FZDy_Dccv4s&feature=relmfu (start at around 31 min).
  2. jcsd
  3. Jul 31, 2012 #2


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    This is only the most simple case. More generally there can be symmetries with explicit time dependence in the symmetry transformation. The most prominent example is invariance under Galilei (Newtonian physics) or Lorentz (special relativistic physics) boosts.

    There has been another thread on this topic recently in this forum. Just search for it!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Question statement Noether's Date
I Optics question: I need parallel illumination for a Contact Image Sensor (CIS) Feb 8, 2018
A Question about indices Jan 13, 2018
B Quick Question about Pendulum Graphs Jan 5, 2018
B Question about vaporization Jan 3, 2018
I Entropy statement question Apr 23, 2016