Algebraic and Topological Approaches for Atomic Nuclei and Related Systems

Project Information

AlgeTopo

Grant agreement ID: 101107805

DOI

10.3030/101107805

Project terminated on 2 December 2024

EC signature date 8 May 2023

Start date 10 September 2023

End date 9 September 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 211 754,88

Coordinated by

COMMISSARIAT A L ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
France

Periodic Reporting for period 1 - AlgeTopo (Algebraic and Topological Approaches for Atomic Nuclei and Related Systems)

Reporting period: 2023-09-10 to 2025-09-09

Summary of the context and overall objectives of the project

The goal of the project is to shed light on the emergence of “simplicity out of complexity” in atomic nuclei. This will be achieved by means of so-called algebraic methods based on group theory, which is the mathematical theory of symmetry. Group theory is of central importance in physics, in particular in the quantum world, and enables one to derive exact results on the basis of general principles without the knowledge of all intricate details of a physical system such as a nucleus. These goals will be achieved in the context of the interacting boson model (IBM), which considers the nucleus in terms of pairs of neutrons and protons, leading to a tremendous simplification of the problem of many (~50 to more than 200) interacting nucleons. Specifically, quantum phase transitions (QPTs), in which the nucleus undergoes a sudden transition as a function of some interaction parameter, can be conveniently described in the framework of the IBM. They are the focus of the project. QPTs have been studied in many domains of physics and some of the developments in condensed-matter physics related to the topology of the transition will be explored in nuclei. A separate but related objective is the application of the algebraic approach to define a new model of the quark-gluon plasma.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project has made significant progress in exploring the emergence of "simplicity out of complexity" in atomic nuclei using algebraic approaches. Key milestones include:
- Detailed studies of quantum phase transitions (QPTs) in odd-mass nuclei, focusing on the zirconium (with Z=40 protons) and niobium (Z=4) isotopes. This work provided new insights into the evolution of nuclear structure, revealing intertwined QPTs in these systems and exploring the influence of single-particle orbitals on collective dynamics with multiple shell-model configurations.
- Initial development of a Monte Carlo code for interacting fermions and bosons (MCFB), which allows for efficient calculations of nuclear structures.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The project has achieved results that go beyond the current state of the art in several areas:
- A comprehensive study of quantum phase transitions (QPTs) in odd-mass zirconium (with Z=40 protons) and niobium (Z=4) isotopes has advanced the understanding of intertwined quantum phase transitions (IQPTs). This work demonstrates how complex phenomena in nuclear structure can be explained through detailed algebraic modelling.
- The initial incorporation of the interacting bosons and fermions in conjunction with a Monte Carlo method will enable precise calculations of structural evolution in even-even, odd-mass and odd-odd nuclei, for the entire nuclear chart.
- These studies provide a novel perspective on the interplay between single-particle and collective behaviours in nuclei, offering benchmarks for experimental data and inspiring further research in nuclear-structure physics.