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arXiv · 1904.00913

Universal physics of bound states of a few charged particles

C. H. Schmickler·H. -W. Hammer·A. G. Volosniev
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Abstract

We study few-body bound states of charged particles subject to attractive zero-range/short-range plus repulsive Coulomb interparticle forces. The characteristic length scales of the system at zero energy are set by the Coulomb length scale $D$ and the Coulomb-modified effective range $r_{\mathrm{eff}}$. We study shallow bound states of charged particles with $D\gg r_{\mathrm{eff}}$ and show that these systems obey universal scaling laws different from neutral particles. An accurate description of these states requires both the Coulomb-modified scattering length and the effective range unless the Coulomb interaction is very weak ($D\to \infty$). Our findings are relevant for bound states whose spatial extent is significantly larger than the range of the attractive potential. These states enjoy universality -- their character is independent of the shape of the short-range potential.

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C. H. Schmickler, H. -W. Hammer, A. G. Volosniev. 2019-10-16. Universal physics of bound states of a few charged particles. https://doi.org/10.1016/j.physletb.2019.135016

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