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KOSUKE NOMURA

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About


Kosuke Nomura, Ph.D.
knomura(at)phy.hr
www.phy.hr/~knomura

I am a theoretical nuclear physicist and assistant professor at the Department of Physics, Faculty of Science, University of Zagreb (UNI-ZG), Croatia. I am also a principal investigator of the project Exotic Nuclear Structure and Dynamics (ExoNSD) within a highly competitive Swiss-Croatian research grant, which allowed me to form my own research group.

I earned my Ph.D. degree at The University of Tokyo in 2012. My thesis was rated as a best Ph.D. work in physics of the year, and was subequently published as book in a special edition of Springer Verlag. After that, I spent about six-and-a-half years as a post-doctoral researcher at University of Cologne in Germany, GANIL in France, and UNI-ZG in Croatia, during which time I was awarded prestigious two JSPS fellowships and an individual Marie-Curie fellowship. I once got a tenure-track position in and moved to Japan in December 2018 but, finally, came back to Croatia in May 2019 to hold my current position at UNI-ZG.

Apart from physics, I like classical music, literature (especially in British, German, French, Chinese, and Japanese classics), philosophy, fine arts, travel, and nature.

Research


The aim of my research is to conduct a world-leading independent research programs to study the structure and dynamics of atomic nuclei. Scientific objectives are pursued in the cutting-edge theoretical nuclear physics, that unifies mathematical modelling of complex systems and advanced scientific computing, which is situated at the interface of nuclear physics, nuclear astrophysics, particle physics, and other finite quantum systems.

The central idea is to develop a universal nuclear structure theory framework that is based on modern nuclear energy density functional theory combined with the algebraic theory of interacting bosons, and apply it to study variety of nuclear properties from stable nuclei towards the frontier of nuclear existence, that are relevant to experiments using radioactive-ion beams. Due to the high numerical complexity encoutered in many of the microscopic nuclear structure calculations when computing spectroscopic properties in heavy nuclei, an innovative method that reduces the redundant computational cost but that preserves essential physics of low-energy nuclear structure will be developed, by devising an ingenious fermion-to-boson mapping technique developed by myself.

My research aims to overcome the current limitations of modern nuclear structure theory in spectroscopic studies of heavy nuclei and, therefore, is in a unique position to study outstanding open problems in low-energy nuclear physics.

Teaching


I will update on regular basis the information about the lectures I am in charge of and make, as much as possible, lecture materials open for students:

Curriculum Vitae


Below is my brief curriculum vitae. Further details can be found in a frequently updated pdf version.

Education

Academic Positions

Honors

Publications


I am author of one book and coauthor of 50+ publications in scientific journals, and give approx. 3-4 invited talks in international conferences per year. Below are some selected publications.

Other publications can be found here (in html) with journal links and, for a complete list of publications including conference proceedings and invited talks, take a look at my CV (in pdf). These external databases:

provide complementary information, such as the number of citations for each of my papers.


Featured as Editors' Suggestion
Structure of even-even Cadmium isotopes from the beyond-mean-field interacting boson model
Kosuke Nomura, and Jan Jolie
Physical Review C 98, 024303 (2018)

The cadmium isotopes have been a classic example for vibrational nuclei. Experiments suggest, however, additional low-lying states which could be attibuted to cross-shell intruder excitations. Based on the microscopic calculation of DFT as input to an interacting boson model calculation, we have been able to identify possible intruder states in the energy spectra of even-even cadmium isotopes.


Invited review
Shape coexistence in the microscopically guided interacting boson model
K. Nomura, T. Otsuka, and P. Van Isacker
Journal of Physics G: Particle and Nuclear Physics 43, 024008 (2016), Focus Issue on Shape Coexistence in Nuclei

Coexistence of different intrinsic shapes and the related spectroscopy in nuclear system has been one of the most prominent and studied subjects in low-energy nuclear physics for many decades. This review article focuses on the study of shape coexistence from the point of view of the interacting boson model, in particular, a method to implement into the IBM framework the configuration mixing, that makes use of the density functional calculation.


Beyond-mean-field boson-fermion model for odd-mass nuclei
K. Nomura, T. Nikšić, and D. Vretenar,
Physical Review C 93, 054305 (2016)

The interplay between single-particle and collective degrees of freedom plays a crucial role in atomic nuclei, most prominently in those nuclei with odd N and/or Z. Theoretical study of the odd N and/or Z systems has not been as extensively pursued as in the case of even-even ones, because one has to consider explicitly both collective and single-particle motions. Here we introduced a method based on the nuclear density functional theory and particle-boson coupling scheme, which allows a detailed and accurate description of spectroscopy in heavy odd-mass nuclei in a computationally very efficient way.


Featured as Editors' Suggestion
Microscopic description of the octupole phase-phase transitions in light actinide and rare-earth nuclei
K. Nomura, D. Vretenar, T. Nikšić, and B.-N. Lu,
Physical Review C 89, 024312 (2014)

Octupole, or pear-shaped, deformation has been a theme of great interest in nuclear physics, and is one of the declared objectives of radioactive-ion beam faciltiies around the world. We present a systematic analysis of low-lying quadrupole and octupole collective states based on the microscopic energy density functional framework. Consistent with the empirical trend, the resulting nuclear structure characteristics show evidence of a shape transition between stable octupole deformation and octupole softness.


Book
Interacting Boson Model from Energy Density Functionals
K. Nomura
Springer Theses Physics, Springer Verlag, Japan, 2013

This Ph.D. work is to bridge the gap between the microscopic nuclear energy density functional theory and the phenomenological interacting boson model, thereby providing a possible microscopic origin of the latter from nucleon degrees of freedom. It points to a universal microscopic description of low-energy collective phenomena in finite nuclei, including exotic nuclei under extreme conditions. Nominated as an outstanding contribution by the University of Tokyo's Physics Department in 2011.


Robust Regularity in γ-Soft Nuclei and Its Microscopic Realization
K. Nomura, N. Shimizu, D. Vretenar, T. Nikšić, and T. Otsuka
Physical Review Letters 108, 132501 (2012)

Shapes of non-spherical nuclei are characterized by axially symmetric deformations - prolate or oblate. There are, however, many nuclei in which this symmetry is broken, and they are characterised by γ-softness. There are two limiting geometrical pictures of non-axial nuclei: the rigid-triaxial rotor and the γ-unstable rotor, and the question as to whether axially asymmetric nuclei are γ-rigid or unstable has been pursued for half a century. Based on the microscopic framework of energy density functionals, it is shown that neither of these pictures is realized in actual nuclei, and that a microscopic description leads to results that are almost exactly in between the two geometrical limits.


Mean-Field Derivation of the Interacting Boson Model Hamiltonian and Exotic Nuclei
K. Nomura, N. Shimizu, and T. Otsuka
Physical Review Letters 101, 142501 (2008)

The interacting boson model has been remarkably successful in reproducing nuclear collective spectra. However, the microscopic origin of the model, i.e., the question why the nucleonic system can be simulated in terms of the bosonic degree of freeom? has not been clarified for decades, except for limited realistic cases of near spherical nuclei. We introduced a novel way of determining Hamiltonian of the IBM. Based on the fact that the potential energy surface of the mean-filed model is simulated by that of the IBM, the parameters of the IBM Hamiltonian are determined. This process is shown to be valid not only for near spherical but also for deformed and γ-unstable shapes. Moreover, unlike conventional IBM studies, we now have a capability of predicting spectroscopy in thus far unknown nuclei.


Contact


Especially those prospective postdoctoral reseaechers and Ph.D. students who are interested to join our group, please feel free to contact me.

Department of Physics
Faculty of Science
University of Zagreb

(in Croatian)
Fizički odsjek
Prirodoslovno-matematički fakultet (PMF)
Sveučilište u Zagrebu

Bijenička cesta 32
HR-10000 Zagreb, Zagreb
Croatia

knomura(at)phy.hr


+385 (0)1 460 5584