Theoretical research in nuclear structure and nuclear collective motion

In the present review, an attempt is made to approach the different facets of the nucleus at low excitation energy from both a microscopic, self-consistent and a collective model approach. Some attention is given on how to relate the two “opposite” approaches to nuclear structure. In a final chapter, we discuss some newly appreciated modes in the nucleus that are specific to the proton and neutron degrees of freedom e.g. the study of intruder states near closed shells and the presence of proton-neutron mixed-symmetry collective motion.

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Learning self-driven collective dynamics with graph networks

Scientific Reports ◽

10.1038/s41598-021-04456-5 ◽

2022 ◽

Vol 12 (1) ◽

Author(s):

Rui Wang ◽

Feiteng Fang ◽

Jiamei Cui ◽

Wen Zheng

Keyword(s):

Machine Learning ◽

Phase Transition ◽

Collective Motion ◽

Transition Process ◽

Initial Position ◽

The Self ◽

Theoretical Research ◽

New Order ◽

Phase Transition Process

AbstractDespite decades of theoretical research, the nature of the self-driven collective motion remains indigestible and controversial, while the phase transition process of its dynamic is a major research issue. Recent methods propose to infer the phase transition process from various artificially extracted features using machine learning. In this thesis, we propose a new order parameter by using machine learning to quantify the synchronization degree of the self-driven collective system from the perspective of the number of clusters. Furthermore, we construct a powerful model based on the graph network to determine the long-term evolution of the self-driven collective system from the initial position of the particles, without any manual features. Results show that this method has strong predictive power, and is suitable for various noises. Our method can provide reference for the research of other physical systems with local interactions.

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SUSYQM in nuclear structure: Bohr Hamiltonian with mass depending on the deformation

HNPS Proceedings ◽

10.12681/hnps.2540 ◽

2019 ◽

Vol 18 ◽

pp. 69

Author(s):

D. Bonatsos ◽

P. E. Georgoudis ◽

D. Lenis ◽

N. Minkov ◽

C. Quesne

Keyword(s):

Quantum Mechanics ◽

Nuclear Structure ◽

Collective Motion ◽

Moment Of Inertia ◽

Supersymmetric Quantum Mechanics ◽

Nuclear Moment ◽

Nuclear Mass

A well known problem of the Bohr Hamiltonian for the description of nuclear collective motion is that the nuclear moment of inertia increases with deformation too fast. We show that this can be avoided by allowing the nuclear mass to depend on the deformation. The resulting Hamiltonian is solved exactly, using techniques of Supersymmetric Quantum Mechanics

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