Computing Spectra of Nuclei

Quantum Electro Dynamics QED forms a low-energy version of the Standard Model SM within quantum electro-magnetics. QED theory agrees to high precision with  precise measurements of the (anomalous) magnetic moment of the electron using a Penning trap including a single electron. This device measures resonances of the electron in a way similar to measuring the spectrum of an atom, or resonance frequencies of a mechanical system, by subjecting the system to input of varying frequency and recording peaks in system output for certain frequencies showing resonance between input to and output from the system. 

The common understanding is that QED describes electrons of atoms and molecules, but not atomic nuclei composed of protons and neutrons asking for an extension of SM to Quantum Chromo Dynamics QCD including the strong force and the weak force of different nature than the Coulomb force of QED. 

The following question was asked 100 years ago during rapid development of quantum mechanics in 1920s with prospects to be all-encompassing: 

• Is it possible that QED can describe not only the electrons of atoms around nuclei with protons, but also also nuclei of atoms as systems of protons and electrons? 

The answer was negative: It is impossible for a nucleus to include an electron, because the nucleus is so small and squeezing an electron into that size would require energies of 100s of MeV, while the total energy of a nucleus per nucleon is around 8 MeV. 

RealNucleus takes up that old idea again from the new perspective of RealQM where charge densities of electrons and protons can meet with continuity, which allows electrons to be localised to the same extent as protons, thus allows electrons to hide inside a nucleus. RealNucleus thus offers a model of a nucleus as a system of non-overlapping charge densities of positive and negative sign interacting by Coulomb potentials. The model shows stability/existence of nuclei with in basic case $Z$ electrons forming a kernel surrounded by a shell system pf $2Z$ protons, with full quantum resolution of both electrons and protons, signifies by negative ground state energies in fair agreement with observation. 

The computational complexity of RealNucleus scales linearly with $Z$ which allows computation of full spectrum even for large $Z$, which is unthinkable with QCD. Results for RealNucleus under way...