We perform a renormalization group analysis of the non-relativistic four-boson problem by means of a simple model with pointlike three- and four-body interactions. We investigate in particular the unitarity point where the scattering length is infinite and all energies are at the atom threshold. We find that the four-body problem behaves truly universally, independent of any four-body parameter. Our findings confirm the recent conjectures of Platter et al. and von Stecher et al. that the four-body problem is universal, now also from a renormalization group perspective. We calculate the corresponding relations between the four- and three-body bound states, as well as the full bound state spectrum and comment on the influence of effective range corrections.
The Three-Body Limit Cycle: Universal Form for General Regulators
Fudan University（复旦大学）；Université Paris-Saclay（巴黎萨克雷大学）；CNRS/IN2P3, IJCLab（法国国家科学研究中心/欧洲核子研究学院，IJCLab）；North Carolina State University（北卡罗来纳州立大学）；European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*), Fondazione Bruno Kessler（核物理及相关领域理论研究中心（ECT*），布鲁诺·凯斯勒基金会）；University of Arizona（亚利桑那大学）；State Key Laboratory of Surface Physics, Fudan University（复旦大学表面物理国家重点实验室）；Hefei National Laboratory（合肥国家实验室）
Non-Hermitian Renormalization Group from a Few-Body Perspective
The University of Tokyo（东京大学）；RIKEN Nishina Center（理化学研究所西村中心）；Quark Nuclear Science Institute, The University of Tokyo（东京大学夸克核科学研究所）；RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)（理化学研究所交叉理论与数学科学中心(iTHEMS)）；Institute for Physics of Intelligence, The University of Tokyo（东京大学智能物理研究所）；RIKEN Center for Emergent Matter Science (CEMS)（理化学研究所涌现物质科学中心(CEMS)）
