- #1
praharmitra
- 311
- 1
We know the covariant Lagrangian of the Lorentz force law. However, in presence of a magnetic monopole, one must add another term to the force law. This term, of course is the Dual Field Tensor, along with the magnetic charge 'g' as follows -
[tex]m \frac{d^2 x^{\mu}}{d {\tau}^2} = \frac{e}{c}F^{\mu \nu} \frac{d x_{\nu}}{d \tau} + \frac{g}{c}G^{\mu \nu} \frac{d x_{\nu}}{d \tau}[/tex]
Where G is the dual field tensor
Could anyone help me with writing the Lagrangian that gives rise to this equation?
Here is what I have tried till now.
1. Solve the original Lagrangian, get the equation of motion. Add the additional term, of G, and work backwards. However, I have realized that the required relation between A (potential) and a (dual potential, if I can call it that) is non-linear and non-local.
[tex] G^{ \mu \nu } = \partial_{\mu} a_{\nu} - \partial_{\nu} a_{\mu} [/tex]
2. So i tried hit and trial, wrote down, using covariance, symmetry, and dimensions as my guides, several possible Lagrangians, and got the corresponding equation of motion, hoping to give the one that i want.
However, I have been unlucky so far. Have been working on it for several hours.
Can such a Lagrangian be written down explicitly in terms of A and a??
[tex]m \frac{d^2 x^{\mu}}{d {\tau}^2} = \frac{e}{c}F^{\mu \nu} \frac{d x_{\nu}}{d \tau} + \frac{g}{c}G^{\mu \nu} \frac{d x_{\nu}}{d \tau}[/tex]
Where G is the dual field tensor
Could anyone help me with writing the Lagrangian that gives rise to this equation?
Here is what I have tried till now.
1. Solve the original Lagrangian, get the equation of motion. Add the additional term, of G, and work backwards. However, I have realized that the required relation between A (potential) and a (dual potential, if I can call it that) is non-linear and non-local.
[tex] G^{ \mu \nu } = \partial_{\mu} a_{\nu} - \partial_{\nu} a_{\mu} [/tex]
2. So i tried hit and trial, wrote down, using covariance, symmetry, and dimensions as my guides, several possible Lagrangians, and got the corresponding equation of motion, hoping to give the one that i want.
However, I have been unlucky so far. Have been working on it for several hours.
Can such a Lagrangian be written down explicitly in terms of A and a??