Remarks on the calculations of charged open string amplitudes: the 1-loop tadpole
Remarks on the calculations of charged open string amplitudes: the 1-loop tadpole
In string theory, there are various physical situations where the world-sheet fields have a shifted moding. For instance, this is the case for the twisted closed string in ZN orbifold or for the charged open string in a constant electro-magnetic field. Because of this feature, it is quite challenging to …