Riisager, Knudåge

Jensen, Niels Martin; Grimley, Daniel M.

doi:10.1093/gmo/9781561592630.article.23471

Cited by 6 publications

(8 citation statements)

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“…An important restriction is the mixing with others states that cannot be avoided if the local density of states is too high. This limits the occurence of halos in excited states, the estimates in [22] for an excitation energy E * use a level distance of D 0 exp(−2 √ aE * ) (with D 0 = 7 MeV and a = A/7.5 MeV) and conclude that s-wave neutron halo states should have binding energy B < 270 keV (A/Z) 2 exp(−4 √ aE * ) and that the restriction for p-waves is Z < 0.44A 4/3 exp(−2 √ aE * ). For now, the main inference from these estimates is that nuclear halos will predominantly occur in ground states or at low excitation energy and therefore is a dripline phenomenon.…”

Section: Basicsmentioning

confidence: 99%

Halos and related structures

2013

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The halo structure originated in nuclear physics but is now encountered more widely. It appears in loosely bound, clustered systems where the spatial extension of the system is significantly larger than that of the binding potentials. A review is given on our current understanding of these structures, with an emphasis on how the structures evolve as more cluster components are added, and on the experimental situation concerning halo states in light nuclei.

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Section: Basicsmentioning

confidence: 99%

Halos and related structures

2013

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“…However, being so high up in the continuum implies that there will be plenty of states with which they can mix. They can therefore be expected to behave in close analogy to halo states at high excitation energy that are known [50] to mix with other states rather than to remain unperturbed. In both cases, there is no quantum number or symmetry that preserves the topology or clustering of the structure.…”

Section: Nuclear Systemsmentioning

confidence: 99%

“…where the core+xn system is unbound for x = 1, 3, 5, .. and bound for x = 2, 4 (and even higher). It has even been suggested that this type of structure may appear also for low masses beyond the dripline [53]. However, one would expect the internal structure of the states to rearrange as neutrons are added.…”

Section: Nuclear Systemsmentioning

confidence: 99%

Higher-Order Brunnian Structures and Possible Physical Realizations

Baas¹,

Fedorov

Jensen

et al. 2014

Ядер. физ.

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We consider few-body bound state systems and provide precise definitions of Borromean and Brunnian systems. The initial concepts are more than a hundred years old and originated in mathematical knot-theory as purely geometric considerations. About thirty years ago they were generalized and applied to the binding of systems in nature. It now appears that recent generalization to higher order Brunnian structures may potentially be realized as laboratory made or naturally occurring systems. With the binding energy as measure, we discuss possibilities of physical realization in nuclei, cold atoms, and condensed matter systems. Appearance is not excluded. However, both the form and the strengths of the interactions must be rather special. The most promising subfields for present searches would be in cold atoms because of external control of effective interactions, or perhaps in condensed-matter systems with non-local interactions. In nuclei, it would only be by sheer luck due to a lack of tunability.

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“…Nuclear structures can vary from spherical mean-field properties, over collective deformations and a variety of other correlations, to bound nuclear clusters each in (almost) inert subsystems [7,[14][15][16]. Very crudely, we can say that nuclei around beta-stability are fairly well described by self-consistent mean-field calculations while approach to the nucleon driplines produces two-and three-body halo structures [17,18]. For excited states at energies close to threshold for cluster separation, the corresponding clusterization is strongly favored [19].…”

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confidence: 99%

Emergence of Clusters: Halos, Efimov States, and Experimental Signals

et al. 2018

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We investigate the emergence of halos and Efimov states in nuclei by use of a newly designed model that combines self-consistent mean-field and three-body descriptions. Recent interest in neutron heavy calcium isotopes makes ^{72}Ca (^{70}Ca+n+n) an ideal realistic candidate on the neutron dripline, and we use it as a representative example that illustrates our broadly applicable conclusions. By smooth variation of the interactions we simulate the crossover from well-bound systems to structures beyond the threshold of binding, and find that halo configurations emerge from the mean-field structure for three-body binding energy less than ∼100 keV. Strong evidence is provided that Efimov states cannot exist in nuclei. The structure that bears the most resemblance to an Efimov state is a giant halo extending beyond the neutron-core scattering length. We show that the observable large-distance decay properties of the wave function can differ substantially from the bulk part at short distances, and that this evolution can be traced with our combination of few- and many-body formalisms. This connection is vital for interpretation of measurements such as those where an initial state is populated in a reaction or by a beta decay.

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Riisager, Knudåge

Cited by 6 publications

References 0 publications

Halos and related structures

Halos and related structures

Higher-Order Brunnian Structures and Possible Physical Realizations

Emergence of Clusters: Halos, Efimov States, and Experimental Signals

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