Recent content by stormyweathers

  1. S

    Manipulating Tensor Expressions to Derive the Poincare Algebra

    Hey guys, as this is a basic QFT question, I wasn't sure to put it in the relativity or quantum section. Since this question specifically is about manipulating tensor expressions, i figured here would be appropriate. My question is about equating coefficients in tensor expressions...
  2. S

    Inverse of a special matrix of arbitrary size

    Hey guys. In a project I'm working on, it would be very convienent to express the inverse of this matrix in terms of its size, NxN. The matrix is \leftbrace \begin{tabular}{c c c c} a & b & \ldots & b \\ b & a & \ldots & b \\ b & b & \ddots & b \\ \vdots & vdots & ldots & b \\ b...
  3. S

    Euler's Fluid Equations: Gradient of a Vector

    Hey guys, I'm not sure how to interpret euler's fluid equations \rho (\partial / \partial t + {\bf U} \cdot ∇) {\bf U} + ∇p = 0 I'm not sure what the meaning of {\bf U} \cdot ∇ {\bf U} is. am I able to simply evaulate the dot product as U_{x}\partial_{x} + U_{y}\partial_{y}+...
  4. S

    Abelian Simple Group / Prime Numbers

    an old thread, but I stumbled upon it looking for homework help so I figured I'd contribute anyway. You must find a normal subgroup to show its not simple.
  5. S

    Proving that the free particle lagrangian is rotationally symmetric

    It seemed more straightforward to apply displacements in the angular directions. To apply a general rotation matrix would be a ton more algebra, no? I need to use infinitesimal rotations because I am trying to prove a continuous symmetry for noether's theorem
  6. S

    Proving that the free particle lagrangian is rotationally symmetric

    Homework Statement Show that the free particle lagrangian is invariant to rotations in $$\Re^{3}$$, but I assume this means invariant up to a gauge term. $$L=m/2 [\dot{R^{2}} + R^{2}\dot{θ^{2}} +R^{2}Sin^{2}(θ)\dot{\phi^{2}}$$ Homework Equations I consider an aribtrary infinitesimal...
  7. S

    Courses What Math Courses Should a Physics Major Take?

    Every physics major knows he needs to take a bunch of math courses. But there are so many offered at my university its making my head spin! I've taken (aside from lower division linear algebra/calculus/DEQ) real analysis and abstract algebra so far, and I've tentatively decided to aim for...
Back
Top