A next-to-leading Luescher formula
Diego Bombardelli
TL;DR
This paper introduces next-to-leading Luescher-like corrections for excited-state energies in integrable theories by modeling excited states as momentum-dependent defects that twist the vacuum. It derives explicit leading and next-to-leading finite-size corrections from the S-matrix, and provides rapidity corrections within an excited-state TBA framework, validated against NLIE results in several relativistic models. The authors also conjecture AdS5/CFT4 generalizations, linking the approach to the Konishi operator and highlighting a practical path to high-loop finite-size corrections. Overall, the work bridges Luescher-type methods with NLIE/TBA formalisms and sets the stage for systematic finite-volume analyses in both relativistic and AdS/CFT contexts.
Abstract
We propose a next-to-leading Luescher-like formula for the finite-size corrections of the excited states energies in integrable theories. We conjecture the expressions of the corrections for both the energy and the particles' rapidities by interpreting the excited states as momenta-dependent defects. We check the resulting formulas in some simple relativistic model and conjecture those for the AdS5/CFT4 case.
