IAS Amplitudes Group Meeting

Abstract: Almost 60 years ago, Dashen, Ma and Bernstein, while at the IAS, put forward a formula to compute the partition function of a relativistic gas at finite temperature in terms of the scattering matrices of its constituents. If correct, such a formula would be very interesting, as it would give access to finite-volume physics from scattering data. Unfortunately, the DMB formula is tricky to use due to various divergences so, despite recent progress, it's still unclear how it should be understood (at least to me). In this very informal discussion, I will introduce the formula and some of the puzzles and questions that it poses, in hopes that they will pique people's curiosity. To motivate the utility of such a formula, I will also discuss some games with its 2-dimensional integrable cousin: the TBA formula. In particular, I will explain how, in that context, causality constraints for the S-matrix lead to bounds on thermodynamic data.