title: Quantum Halo States in Helium Tetramers.
abstract: The universality of quantum halo states enables a comparison of systems from different fields of physics, as demonstrated in two- and three-body clusters. In the present work, we studied weakly bound helium tetramers in order to test whether some of these four-body realistic systems qualify as halos. Their ground-state binding energies and structural properties were thoroughly estimated using the diffusion Monte Carlo method with pure estimators. Helium tetramer properties proved to be less sensitive on the potential model than previously evaluated trimer properties. We predict the existence of realistic four-body halo4He23He2, whereas4He4and4He33He are close to the border and thus can be used as prototypes of quasi-halo systems. Our results could be tested by the experimental determination of the tetramers' structural properties using a setup similar to the one developed for the study of helium trimers.
authors.affiliation: Faculty of Science, University of Split , Ruđera Boškovića 33, HR-21000 Split, Croatia.
authors.forename: Petar
authors.identifier: http://orcid.org/0000-0002-8551-8989
authors.initials: P
authors.lastname: Stipanović
authors.affiliation: Faculty of Science, University of Split , Ruđera Boškovića 33, HR-21000 Split, Croatia.
authors.forename: Leandra
authors.initials: L
authors.lastname: Vranješ Markić
authors.affiliation: Departament de Física, Campus Nord B4-B5, Universitat Politècnica de Catalunya , E-08034 Barcelona, Spain.
authors.forename: Jordi
authors.identifier: http://orcid.org/0000-0002-0273-3457
authors.initials: J
authors.lastname: Boronat