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Energy density in Stress Energy Tensor

  1. Oct 18, 2012 #1
    Hello,

    I am new to this, if somebody could help me:

    The energy density in stress-energy-tensor is the amount of energy stored in a given system per unit mass. The T00=energy density.

    In a 4x4 matrix, we generally start with 1,1. Why it is 0,0?

    Secondly, what does energy density mean mathematically? I am unable to get over the concept.

    Thanks,

    -- Shounak
     
  2. jcsd
  3. Oct 18, 2012 #2
    It's common (but not universal) to number the time dimension as 0 instead of 4 (x, y, and z or other spatial directions would be 1-3). It doesn't make a big difference either way.

    Energy density = energy per unit volume.
     
  4. Oct 18, 2012 #3
    Ok, thanks a lot.
     
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