2021/05/14 by Stephan Stieberger, Stieberger, S.
Computer Science · Physics and Astronomy · #Black Holes and Theoretical Physics #Computational Physics and Python Applications #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.2105.06888
openalex publication_date 2021/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We express one-loop string amplitudes involving both open and closed strings as sum over pure open string amplitudes. These findings generalize the analogous tree-level result to higher loops and extend the tree-level observation that in gravitational amplitudes a graviton can be traded for two gluons. Our results are derived from analytic continuation of closed string world-sheet coordinates on the cylinder resulting in pairs of real open string coordinates located at the two cylinder boundaries subject to a one-loop kernel. The latter depends on the loop momentum flowing between the two cylinder boundaries and relates to intersection theory for twisted cycles. Finally, contact is made with one-loop open string monodromy relations. The latter contain a boundary term, which is related to non-physical contours on the cylinder. A physical interpretation of the latter in terms of a closed string insertion is given.