# Nuclear Physics Theory

Lead Research Organisation:
University of York

Department Name: Physics

### Abstract

To establish a Chair in Nuclear physics theory at the University of York with the overall goal of enhancing the provision of nuclear theory within the UK.

### Planned Impact

It is expected that this appointment will both complement the exisiting nuclear theory group work as well as enhance the provision of nuclear physics theory in the UK.

### Publications

Baczyk P
(2019)

*Isobaric multiplet mass equation within nuclear density functional theory*in Journal of Physics G: Nuclear and Particle Physics
Baczyk P
(2015)

*Strong-interaction Isospin-symmetry Breaking Within the Density Functional Theory*in Acta Physica Polonica B Proceedings Supplement
Baczyk P
(2018)

*Isospin-symmetry breaking in masses of N ? Z nuclei*in Physics Letters B
Baczyk P
(2017)

*Mirror and Triplet Displacement Energies Within Nuclear DFT: Numerical Stability*in Acta Physica Polonica B
Becker P
(2018)

*Skyrme N2LO Pseudo-potential for Calculations of Properties of Atomic Nuclei*in Acta Physica Polonica B
Becker P
(2015)

*Tools for incorporating a D-wave contribution in Skyrme energy density functionals*in Journal of Physics G: Nuclear and Particle Physics
Becker P
(2017)

*Solution of Hartree-Fock-Bogoliubov equations and fitting procedure using the N2LO Skyrme pseudopotential in spherical symmetry*in Physical Review C
Bennaceur K
(2017)

*Nonlocal energy density functionals for pairing and beyond-mean-field calculations*in Journal of Physics G: Nuclear and Particle Physics
Chamel N
(2015)

*Brussels--Montreal Nuclear Energy Density Functionals, from Atomic Masses to Neutron Stars*in Acta Physica Polonica B
Davesne D
(2015)

*Extended Skyrme pseudopotential deduced from infinite nuclear matter properties*in Physical Review CDescription | (I) Owing to a rapid increase of computer power available to physicists, exact solutions determining quantum states of many-fermion systems, as those of electrons in molecules or nucleons in nuclei, become now possible. Such ab initio solutions may employ degrees of freedom of individual constituent fermions, but also can be formulated in terms of an ab initio density functional theory, which uses one-body densities as fundamental degrees of freedom. The latter approach is simpler and can be employed to study systems of many more particles. However, the link between these two approaches has been established only formally, and a constructive methodology to build an ab initio density functionals is not known. I proposed a manageable method to derive a class of model density functionals directly from the ab initio wave-function-based solutions. The main idea is to probe the system not by placing it in an external one-body potential, but by letting the particles interact with model two-body potentials - the same ones that are next used to generate functionals through the Hartree-Fock-like averages. The proposed method may pave the way towards building density functionals that do not rely on sheer adjustments of parameters to data, but are rooted in fundamental properties of the underlying many-body Hamiltonians. I anticipate that the proposed method may become a game-changing approach to study physics of many-fermion systems. Even if practical implementations may still require intensive high-performance computing of months or years to complete, the ab-initio-derived model density functionals can become a tool of choice for studying large or exotic systems that can be neither computed nor measured in laboratories. (II) We proposed to use two-body regularized finite-range pseudopotential to generate nuclear energy density functional (EDF) in both particle-hole and particle-particle channels, which makes it free from self-interaction and selfpairing, and also free from singularities when used beyond mean field. We derived a sequence of pseudopotentials regularized up to next-to-leading order and next-to-next-to-leading order, which fairly well describe infinite-nuclear-matter properties and finite open-shell paired and/or deformed nuclei. Since pure two-body pseudopotentials cannot generate sufficiently large effective mass, the obtained solutions constitute a preliminary step towards future implementations, which will include, e.g., EDF terms generated by three-body pseudopotentials. |

Exploitation Route | The proposed methodology may find applications in numerous fields of many-body physics |

Sectors | Chemicals,Digital/Communication/Information Technologies (including Software),Education |

Description | FiDiPro |

Organisation | University of Jyvaskyla |

Department | Department of Physics |

Country | Finland |

Sector | Academic/University |

PI Contribution | Long-term scientific collaboration and publications |

Collaborator Contribution | Long-term scientific collaboration and publications |

Impact | 10.1103/PhysRevC.97.024306, 10.1088/1361-6471/aa691e, 10.1088/1361-6471/aa5fd7, 10.1016/j.cpc.2017.03.007 |

Start Year | 2007 |

Description | Lyon Claud Bernard |

Organisation | University of Lyon |

Country | France |

Sector | Academic/University |

PI Contribution | Long-term scientific collaboration and publications |

Collaborator Contribution | Long-term scientific collaboration and publications |

Impact | 10.1088/1361-6471/aa691e, 10.1088/1361-6471/aa5fd7 |

Description | MSU Nazarewicz |

Organisation | Michigan State University |

Department | Department ofÂ PhysicsÂ And Astronomy |

Country | United States |

Sector | Academic/University |

PI Contribution | Long-term collaboration and publications |

Collaborator Contribution | Long-term collaboration and publications |

Impact | 10.5506/APhysPolB.46.575 |

Description | Warsaw IFT |

Organisation | University of Warsaw |

Country | Poland |

Sector | Academic/University |

PI Contribution | Long-term scientific collaboration and publications |

Collaborator Contribution | Long-term scientific collaboration and publications |

Impact | 10.1103/PhysRevC.94.024306, 10.1016/j.cpc.2017.03.007, 10.5506/APhysPolB.48.259, 10.1016/j.physletb.2017.12.068 |