Multi-fermion systems with contact theories

0542747 - ÚJF 2022 RIV NL eng J - Journal Article
Schäfer, Martin - Contessi, L. - Kirscher, J. - Mareš, Jiří
Multi-fermion systems with contact theories.
Physics Letters. B. Roč. 816, MAY (2021), č. článku 136194. ISSN 0370-2693. E-ISSN 1873-2445
R&D Projects: GA ČR GA19-19640S
Institutional support: RVO:61389005
Keywords : contact effective field theory * pionless * renormalization * unitarity * universality
OECD category: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
Impact factor: 4.950, year: 2021
Method of publishing: Open access
https://doi.org/10.1016/j.physletb.2021.136194

We address the question of minimal requirements for the existence of quantum bound states. In particular, we demonstrate that a few-body system with zero-range momentum-independent two-body interactions is unstable against decay into clusters, if mixed-symmetry of its wave function is enforced. We claim that any theory in which the two-body scattering length is much larger than any other scale involved exhibits such instability. We exemplify this with the inability of the leading-order pionless effective field theory to describe stable states of A > 4 nuclei. A finite interaction range is identified as a sufficient condition for a bound mixed-symmetry system. The minimal value of this range depends on the proximity of a system to unitarity, on the number of constituents, and on the particular realization of discrete scale invariance of the three-body spectrum.
Permanent Link: http://hdl.handle.net/11104/0320098