engleski

Ground state properties of weakly bound few-body systems

The results of the recent research in quantum systems will be presented. Ground state properties of weakly bound systems consisting of few particles are explored with a special emphasis on a universality of quantum halo states - weakly bound systems with a radius extending well into the classically forbidden region. The focus of the study are clusters consisting of T$\downarrow$, D$\downarrow$, $^3$He, $^4$He and alkali atoms. The study of realistic systems is supplemented by model calculations in order to analyze how low-energy properties depend on the interaction potential. The use of variational and diffusion Monte Carlo methods enabled very precise calculation of both size and binding energy of the trimers and tetramers. Using dimensionless measures of the binding energy and cluster size, studied atomic clusters are compared to other known halos in different fields of physics. Characteristic scaling lengths, which make size-energy ratio to be universal, are selected. As the scaled binding energy decreases, tango type trimers separate from Borromean type~[1]. Research is extended to tetramers. Furthermore, the structural properties of different trimers are compared with recently published experimental results~ [2, 3] obtained by Coulomb explosion imaging of diffracted clusters. [1] Stipanović P. et al., Phys. Rev. Lett. 113, 253401 (2014). [2] Voigtsberger J. et al., Nature Communications 5, 5765 (2014). [3] Kunitski M. et al., Science 348, 551 (2015).

quantum clusters ; trimers ; tetramers ; halo states ; universality ; helium ; quantum Monte Carlo

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