1. The problem statement, all variables and given/known data
This is not really a problem but I was going over my lecture notes and I see [itex] \mathscr{H}=\frac{1}{2}\left(\pi^{2} + \vec{\nabla}\phi \cdot \vec{\nabla}\phi + m^{2}\phi^{2}\right) [/itex] and [itex]\frac{\partial\mathscr{H}}{\partial\phi} = -\nabla^{2}\phi + m^{2}\phi [/itex]
2. Relevant equations
3. The attempt at a solution
I would think that [itex]\frac{\partial\mathscr{H}}{\partial\phi} = \nabla^{2}\phi + m^{2}\phi [/itex]. But I don't know where the minus sign is coming from.
This is not really a problem but I was going over my lecture notes and I see [itex] \mathscr{H}=\frac{1}{2}\left(\pi^{2} + \vec{\nabla}\phi \cdot \vec{\nabla}\phi + m^{2}\phi^{2}\right) [/itex] and [itex]\frac{\partial\mathscr{H}}{\partial\phi} = -\nabla^{2}\phi + m^{2}\phi [/itex]
2. Relevant equations
3. The attempt at a solution
I would think that [itex]\frac{\partial\mathscr{H}}{\partial\phi} = \nabla^{2}\phi + m^{2}\phi [/itex]. But I don't know where the minus sign is coming from.
via Physics Forums RSS Feed http://www.physicsforums.com/showthread.php?t=713460&goto=newpost
0 commentaires:
Enregistrer un commentaire