Speaker
Description
In recent years, the finite-volume Lüscher formalism has become a well-established
tool to study the two-body scattering processes on the lattice. The formalism has been
generalized to the case of the coupled two-body channels and has been successfully
applied for the analysis of the lattice data for different scattering processes. A closely
related method, known under the name of the Lellouch-Lüscher approach, is being used
for the extraction of the decay matrix elements with the two-body final states.
In difference to this, the progress in the study of the systems with three and more particles
on the lattice lies behind, albeit a number of important results have been obtained lately.
In my talk, I plan to review the basic ideas, which provide basis for the extraction of
the physical observables, defined in the infinite volume, from the finite-volume lattice
spectra. Various approaches to this problem will be considered and compared. In
particular, the three-body quantization condition will be discussed in detail. Perturbative
expansion of the energy levels will be performed, and the optimal strategies for the analysis
of data will be worked out. As an illustration, the recent lattice results in the three-body
sector will be presented. In conclusion, the perspectives of the further development in the
field will be briefly discussed.
