Hi all,
As a blind follower of QFT from the sidelines (the joys of the woefully inadequate teaching of theory to exp. particle physics students...), I have just realized that I've never actually gone further than deriving the Dirac equation, and then just used the Dirac Lagrangian density as...
Hello,
I took an Electrodynamics course this semester, where we derived Maxwell's equations from the field's Lagrangian density.
As a motivation, we "looked" for a scalar (in the relativistic sense) having something to do with EM fields - and had we found one we would have declared it a...
we know the lagrangian l=ke-pe right
in case of fields is called "lagrangian density"
let particle with mass "m" and position "x"
it kientic energy= 1/2(mv^2)
so lagrangian =1/2(mv^2)-v(x) , v(x)=potential energy
in case the field lagrangian density
how can i determine the lagragian...
Why does the Lagrangian density for the EM field in a dielectric medium take the form d^3 \bf x \left[ \epsilon \bf E^2 - \bf B^2 \right]? I can see that the expression for Lagrangian density has units of energy per unit volume as you would expect but that's about it. Much appreciated.
Here's the problem. For a neutral vector field V_{\mu} we have the Lagrangian density
\mathcal{L} = -\frac{1}{2}(\partial_{\mu}V_{\nu})(\partial^{\mu}V^{\nu})+\frac{1}{2}(\partial_{\mu}V^{\mu})(\partial_{\nu}V^{\nu})+\frac{1}{2}m^2V_{\mu}V^{\mu}
We are then going to use the Euler-Lagrange...