Witold (Witek) Nazarewicz
Nuclear Structure
Atomic nuclei, the core of matter and the fuel of stars, are selfbound collections of protons and neutrons (nucleons) that interact through forces that have their origin in quantum chromodynamics. Nuclei comprise 99.9% of all baryonic matter in the Universe. The complex nature of the nuclear forces among protons and neutrons yields a diverse and unique variety of nuclear phenomena, which form the basis for the experimental and theoretical studies. Developing a comprehensive description of all nuclei, a longstanding goal of nuclear physics, requires theoretical and experimental investigations of rare atomic nuclei, i.e. systems with neutrontoproton ratios larger and smaller than those naturally occurring on earth. The main area of my professional activity is the theoretical description of those exotic, shortlived nuclei that inhabit remote regions of nuclear landscape. This research invites a strong interaction between nuclear physics, manybodyproblem, and high performance computing. Key scientific themes that are being addressed by my research are captured by overarching questions:

How did visible matter come into being and how does it evolve?

How does subatomic matter organize itself and what phenomena emerge?

Are the fundamental interactions that are basic to the structure of matter fully understood?

How can the knowledge and technological progress provided by nuclear physics best be used to benefit society?
Quantum ManyBody Problem
Heavy nuclei are splendid laboratories of manybody science. While the number of degrees of freedom in heavy nuclei is large, it is still very small compared to the number of electrons in a solid or atoms in a mole of gas. Nevertheless, nuclei exhibit behaviors that are emergent in nature and present in other complex systems. For instance, shell structure, symmetry breaking phenomena, collective excitations, and superconductivity are found in nuclei, atomic clusters, quantum dots, small metallic grains, and trapped atom gases.
Although the interactions of nuclear physics differ from the electromagnetic interactions that dominate chemistry, materials, and biological molecules, the theoretical methods and many of the computational techniques to solve the quantum manybody problems are shared. Examples are abinitio and configuration interaction methods, and the Density Functional Theory, used by nuclear theorists to describe light and heavy nuclei and nucleonic matter.
Quality Control
As in other areas of science, nuclear structure uses a cycle of “observationtheorypredictionexperiment“, to investigate phenomena, build knowledge, and define future research. Such an approach, known as the scientific method, guides the relationship between theory and experiment: theory is modified or rejected based on new experimental data, and the improved theory can be used to make predictions that guide future measurements. The positive feedback in the experimenttheory cycle can be enhanced if statistical methods and computational methodologies are applied to determine the uncertainties of model parameters and calculated observables. In partnership with applied mathematics and computer science, modern nuclear structure theory strives to estimate errors on predictions and assess extrapolations. This is essential for developing predictive capability, as theoretical models are often applied to entirely new nuclear systems and conditions that are not accessible to experiment.
Physics of FRIB
The Facility for Rare Isotope Beams will be a worldleading laboratory for the study of nuclear structure, reactions and astrophysics. Experiments with intense beams of rare isotopes produced at FRIB will guide us toward a comprehensive description of nuclei, elucidate the origin of the elements in the cosmos, help provide an understanding of matter in neutron stars and establish the scientific foundation for innovative applications of nuclear science to society. FRIB will be essential for gaining access to key regions of the nuclear chart, where the measured nuclear properties will challenge established concepts, and highlight shortcomings and needed modifications to current theory. Conversely, nuclear theory will play a critical role in providing the intellectual framework for the science at FRIB, and will provide invaluable guidance to FRIB’s experimental programs.
Selected Publications
The limits of nuclear mass and charge, W. Nazarewicz, Nature Phys. 14, 537 (2018).
Electron and nucleon localization functions of oganesson: Approaching the ThomasFermi limit, P. Jerabek, B. Schuetrumpf, P. Schwerdtfeger, and W. Nazarewicz, Phys. Rev. Lett. 120, 053001 (2018)
Challenges in Nuclear Structure Theory, W. Nazarewicz, J. Phys. G 43, 044002 (2016).
Neutron Drip Line in the Ca Region from Bayesian Model Averaging, L. Neufcourt, Y. Cao, W. Nazarewicz, E. Olsen, and F. Viens, Phys. Rev. Lett. 122, 062502 (2019)
Formation and distribution of fragments in the spontaneous fission of ^{240}Pu'', Sadhukhan, C.L. Zhang, W. Nazarewicz, and N. Schunck, Phys. Rev. C 96, 061301(R) (2017)
Puzzling twoproton decay of ^{67}Kr, S. M. Wang and W. Nazarewicz, Phys. Rev. Lett. 120, 212502 (2018)
Pairing NambuGoldstone modes within nuclear density functional theory, N. Hinohara and W. Nazarewicz, Phys. Rev. Lett. {\bf 116}, 152502 (2016)
Impact of nuclear mass uncertainties on the r process, D. Martin, A. Arcones, W. Nazarewicz, and E. Olsen, Phys. Rev. Lett. 116, 121101 (2016)
Challenges in Nuclear Structure Theory, W. Challenges in Nuclear Structure Theory, W. Nazarewicz, J. Phys. G 43, 044002 (2016)
Twistaveraged boundary conditions for nuclear pasta HartreeFock calculations, Schuetrumpf and W. Nazarewicz, Phys. Rev. C 92, 045806 (2015)
"The limits of the nuclear landscape," J. Erler, N. Birge, M. Kortelainen, W. Nazarewicz, E. Olsen, A.M. Perhac, and M. Stoitsov, Nature 486, 509 (2012).
"Spontaneous fission lifetimes from the minimization of selfconsistent collective action," J. Sadhukhan, K.Mazurek, A. Baran, J. Dobaczewski, W. Nazarewicz and J. A. Sheikh, Phys. Rev. C 88, 064314 (2013).