The two-positron gluic bond as a manifestation of "super" van der Waals interactions

TL;DR

This paper reveals that a novel two-positron gluic bond in a PsH-based complex is a strong, dispersion-like interaction driven by quantum correlations, representing a 'super' van der Waals bond with unusually high stability.

Contribution

It demonstrates that the stabilizing interaction in the (PsH)2 complex arises from quantum correlations beyond mean-field models, defining a new 'super' van der Waals bond.

Findings

The interaction is driven by quantum correlations between positrons.

The bond cannot be explained by mean-field or electron-electron correlation models.

The (PsH)2 complex is stabilized by a 'super' van der Waals bond with high dissociation energy.

Abstract

Recently, it has been demonstrated theoretically that the interaction of two PsH atoms, each being a stable bound state of a hydrogen atom and a positronium atom, is attractive, leading to the formation of a molecular complex denoted as (PsH)2. However, the physical nature of this interaction has remained elusive. In the present study, we show that the stabilizing mechanism is entirely encoded in the quantum correlations between the two positrons and, to a lesser extent, in the electron-positron correlations. Notably, the interaction cannot be recovered at the mean-field (Hartree-Fock) level, nor by computational models that include only electron-electron correlation effects. Accordingly, the bond formed between PsH units, termed here a two-positron gluic bond to emphasize its fundamentally distinct character from the two-positron covalent bonds present in pure antimatter molecules, emerges only when matter and antimatter particles form a common bound state. When classified within the framework of known bonding mechanisms, this gluic bond falls into the category of stabilizing dispersion interactions, giving rise to a van der Waals complex. However, its remarkably large bond dissociation energy, compared with those of strongly bonded van der Waals complexes of similar size, reveals an anomalously strong interaction. For this reason, we propose that (PsH)2 is most appropriately described as a "super" van der Waals complex stabilized by a "super" van der Waals bond.