A new derivation of Luscher F-term and fluctuations around the giant magnon

Understand

In this paper we give a new derivation of the generalized Luscher F-term formula from a summation over quadratic fluctuations around a given soliton.

• The result is very general providing that S-matrix is diagonal and is valid for arbitrary dispersion relation.
• We then apply this formalism to compute the leading finite size corrections to the giant magnon dispersion relation coming from quantum fluctuations.