https://doi.org/10.1140/epjc/s10052-018-6325-8
Regular Article - Theoretical Physics
Two- and three-body interactions in 
theory from lattice simulations
1
IFIC, CSIC-Universitat de València, 46980, Paterna, Spain
2
HISKP and BCTP, Rheinische Friedrich-Wilhelms Universität Bonn, 53115, Bonn, Germany
* e-mail: fernando.romero@uv.es
Received:
12
June
2018
Accepted:
10
October
2018
Published online:
22
October
2018
We calculate the one-, two- and three-particle energy levels for different lattice volumes in the complex theory on the lattice. We argue that the exponentially suppressed finite-volume corrections for the two- and three-particle energy shifts can be reduced significantly by using the single particle mass, which includes the finite-size effects. We show numerically that, for a set of bare parameters, corresponding to the weak repulsive interaction, one can reliably extract the two- and three-particle energy shifts. From those, we extract the scattering length, the effective range and the effective three-body coupling. We show that the parameters, extracted from the two- and three-particle energy shifts, are consistent. Moreover, the effective three-body coupling is significantly different from zero.
© The Author(s), 2018
