Problems in higher genus superstring amplitudes

          @misc{ pirsa_PIRSA:08100057,
            doi = {10.48660/08100057},
            url = {https://pirsa.org/08100057},
            author = {Cacciatori, Sergio},
            keywords = {Quantum Information},
            language = {en},
            title = {Problems in higher genus superstring amplitudes},
            publisher = {Perimeter Institute},
            year = {2008},
            month = {oct},
            note = {PIRSA:08100057 see, \url{https://pirsa.org}}
          }
          

Abstract

I would like to provide a short, possibly elementary, introduction to the problem of computing string amplitudes at higher genus for superstrings. Essentially, I will recall which is the mathematical problem in defining the path integral measure (which has a well defined algebraic geometry realization for bosonic strings) and the solution proposed by d~@~YHocker and Phong for the genus 2 case. Their main results are the chiral splitted form of the measure, and its explicit expression in genus two. They proposed the splitting form to work at any genus and assumed some restriction for the explicit form which however did not permitted them to find a solution for genera higher then 2. I will tell something about the technology which permitted us to find explicit solutions for genus 3 and four. Indeed, we showed that the restrictions imposed by d~@~YHocker and Phong have no solution whereas the most general form compatible with modular invariance and clustering provide a unique solution, at least for genus 3 and 4. I will try to be as less technical as possible.