Researcher Profile and Settings

Master

Affiliation (Master)

• Faculty of Science　Physics　Nonlinear Physics

Affiliation (Master)

• Faculty of Science　Physics　Nonlinear Physics

researchmap

Profile and Settings

Affiliation

• Hokkaido University, Faculty of Science, Associate Professor
• Hokkaido University, Nuclear Reaction Data Center, Director

Degree

• Doctor of Science（2012/03 The University of Tokyo）

Profile and Settings

• Name (Japanese)

  Nomura

• Name (Kana)

  Kosuke

• Name

  S-4774-2019, 202101007940427485

Alternate Names

https://nt.sci.hokudai.ac.jp/nomura/

Affiliation

• Hokkaido University, Faculty of Science, Associate Professor
• Hokkaido University, Nuclear Reaction Data Center, Director

Achievement

Research Interests

• 原子核理論   

Research Areas

• Natural sciences / Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

Research Experience

• 2023/04 - Today Hokkaido University Faculty of Science Associate Professor
• 2019/05 - 2023/02 University of Zagreb Faculty of Science Assistant Professor
• 2018/12 - 2019/04 Japan Atomic Energy Agency Advanced Science Research Center Excellent Young Researcher
• 2018/01 - 2018/11 University of Zagreb Faculty of Science Postdoc
• 2016/04 - 2017/10 University of Tsukuba Center for Computational Sciences JSPS Postdoc Fellow
• 2015/10 - 2016/03 University of Zagreb Faculty of Science Postdoc
• 2015/09 - 2015/09 IPN Orsay Postdoc
• 2013/09 - 2015/08 CEA GANIL Marie-Curie Fellow
• 2012/04 - 2013/03 Universität zu Köln Institut für Kernphysik JSPS Postdoc Fellow
• 2009/04 - 2012/03 The University of Tokyo Graduate School of Science Department of Physics JSPS Fellow

Education

• 2009/04 - 2012/03  The University of Tokyo  Graduate School of Science  Department of Physics
• 2007/04 - 2009/03  The University of Tokyo  Graduate School of Science  Department of Physics
• 2005/04 - 2007/03  The University of Tokyo  Faculty of Science  Department of Physics
• 2003/04 - 2005/03  The University of Tokyo  College of Arts and Sciences

Awards

• 2016/03 Physical Society of Japan 10th Young Scientist Award (Division of Nuclear Theory)
   

  受賞者: Kosuke Nomura
• 2012/03 Springer Springer Theses Prize
   

  受賞者: Kosuke Nomura
• 2012/03 School of Science, The University of Tokyo Dean's Award (for Ph.D.)
   

  受賞者: Kosuke Nomura
• 2009/03 School of Science, The University of Tokyo Dean's Award (for M.Sc.)
   

  受賞者: Kosuke Nomura

Published Papers

• Effects of pairing strength on the nuclear structure and double-β decay predictions within the mapped interacting boson model

  K. Nomura

  Physical Review C 110 (2) 024304-1 - 024304-19 2469-9985 2024/08/08 [Refereed]
  
• Collectivity at the prolate-oblate transition: The 2_1^+ lifetime of 190W

  E. Şahin, V. Werner, A.K. Mistry, M. Rudigier, K. Nomura, J. Jolie, N. Pietralla, P.H. Regan, G. Ağgez, H.M. Albers, U. Ahmed, Ö. Aktaş, A. Algora, S. Alhomaidhi, C. Appleton, T. Arıcı, M. Armstrong, A. Banerjee, J. Benito, G. Benzoni, A. Blazhev, P. Boutachkov, A.M. Bruce, B. Cederwall, M.M.R. Chishti, M.L. Cortés, F. Crespi, B. Das, T. Davinson, T. Dickel, M. Doncel, A. Ertoprak, A. Esmaylzadeh, L.M. Fraile, E.R. Gamba, J. Gerl, M. Górska, J. Ha, E. Haettner, O. Hall, H. Heggen, C. Hornung, N. Hubbard, S. Jazrawi, P.R. John, C.E. Jones, V. Karayonchev, E. Kazantseva, R. Kern, L. Knafla, I. Kojouharov, P. Koseoglou, G. Kosir, D. Kostyleva, N. Kurz, N. Kuzminchuk, M. Llanos-Expósito, R. Lozeva, D. Mengoni, T.J. Mertzimekis, M. Mikolajczuk, A.I. Morales, I. Mukha, J.R. Murias, B.S. Nara-Singh, S.E.A. Orrigo, J. Pellumaj, S. Pelonis, S. Pietri, S. Pigliapoco, Zs. Podolyák, M. Polettini, K. Rezynkina, H.A. Rösch, H. Schaffner, Ch. Scheidenberger, L. Sexton, P.-A. Söderström, Y.K. Tanaka, J.J. Valiente-Dobón, P. Vasileiou, J. Vasiljević, J. Vesic, H. Weick, J. Wiederhold, A. Yaneva, G. Zhang, J. Zhao, A. Zyriliou

  Physics Letters B 857 138976 - 138976 0370-2693 2024/08 [Refereed]
  
• Weakening of N = 28 shell gap and the nature of 0+2 states

  Bhoomika Maheshwari, Kosuke Nomura

  Journal of Physics G: Nuclear and Particle Physics 51 (9) 095101 - 095101 0954-3899 2024/07/26 [Refereed]
   

  Abstract The work reports a novel application of the interacting boson model in light-mass region around ⁴⁸Ca, that takes into account intruder states and configuration mixing. The model is shown to provide a reasonable description of the observed low-lying yrast and yrare states of the N = 28 even–even isotones from Si to Fe, and even–even Ca isotopes. The nature of states is addressed in terms of the competition between spherical and deformed intruder configurations, and the rigidity of the N = 28 shell gap is tested, particularly for ⁴⁴S. The isomer in ⁴⁴S is shown to arise from a weak mixing between the two configurations and called as shape isomer. The unresolved low-lying spectra in ⁴⁶Ar is also approached using the core-excitations across N = 28 shell. The SU(3) structure in ⁴²Si is supported by the present calculation. The nearly spherical nature of ⁵⁰Ti, ⁵²Cr, ⁵⁴Fe and ^42,44,46Ca isotopes is found, while the core excitations are found to be essential for the description of yrare states. Shell model calculation is also performed for comparison.
• Parameter dependence of the β-decay properties of neutron-rich Zr isotopes within the interacting boson model

  M. Homma, K. Nomura

  Physical Review C 110 (1) 014303-1 - 014303-15 2469-9985 2024/07/01 [Refereed]
  
• Microscopic description of hexadecapole collectivity in even-even rare-earth nuclei near N=90

  L. Lotina, K. Nomura

  Physical Review C 044324-1 - 044324-14 2024/04/22 [Refereed]
  
• Systematic shell-model study for structure and isomeric states in 200−210Po isotopes

  Sakshi Shukla, Praveen C. Srivastava, Kosuke Nomura, Larry Zamick

  Nuclear Physics A 1044 122842 - 122842 0375-9474 2024/04 [Refereed]
  
• Low-energy structure and β -decay properties of neutron-rich nuclei in the region of a shape phase transition

  Kosuke Nomura

  Physical Review C 034319-1 - 034319-18 2024/03/27 [Refereed]
  
• Impacts of hexadecapole deformations on the collective energy spectra of axially deformed nuclei

  L. Lotina, K. Nomura

  Physical Review C 109 (3) 034304-1 - 034304-6 2469-9985 2024/03/05 [Refereed]
  
• Investigating the prolate-to-oblate shape phase transition: Lifetime measurements and γ spectroscopy of the low-lying negative parity structure in 193Os

  L. Knafla, K. Nomura, A. Esmaylzadeh, A. Harter, J. Jolie, V. Karayonchev, Y. H. Kim, U. Köster, M. Ley, C. Michelagnoli, A. Pfeil, J.-M. Régis, F. von Spee

  Physical Review C 109 (1) 2469-9985 2024/01/10 [Refereed]
  
• Coulomb excitation of 96Mo

  R. Russell, J. Heery, J. Henderson, C. R. Hoffman, T. Beck, C. Cousins, P. Farris, A. Gade, S. A. Gillespie, A. Hill, H. Iwasaki, S. Kisyov, A. N. Kuchera, B. Longfellow, C. Müller-Gatermann, K. Nomura, E. Rubino, R. Salinas, A. Sanchez, D. Weisshaar, C. Y. Wu, J. Wu

  Physical Review C 108 (6) 2469-9985 2023/12/19 [Refereed]
  
• Octupole deformation in 143,145,146Ba

  N.T. Brewer, E.H. Wang, W.A. Yzaguirre, J.H. Hamilton, K. Nomura, A.V. Ramayya, S.H. Liu, J.K. Hwang, B.M. Musangu, J.M. Eldridge, C.J. Zachary, Y.X. Luo, J.O. Rasmussen, S.J. Zhu, C. Goodin, G.M. Ter-Akopian, A.V. Daniel, Yu.Ts. Oganessian

  Nuclear Physics A 1039 122738 - 122738 0375-9474 2023/11 [Refereed]
  
• Lifetime measurements in 99Nb and 99Zr: Investigation of shape coexistence

  A. Pfeil, K. Nomura, N. Gavrielov, J.-M. Régis, U. Köster, Y. H. Kim, A. Esmaylzadeh, A. Harter, J. Jolie, L. Knafla, M. Ley, V. Karayonchev

  Physical Review C 108 (3) 034310-1 - 034310-14 2469-9985 2023/09/19 [Refereed]
  
• Classical and Bayesian error analysis of the relativistic mean-field model for doubly magic nuclei

  M. Imbrišak, K. Nomura

  Physical Review C 108 (2) 024321-1 - 024321-9 2469-9985 2023/08/28 [Refereed]
  
• Microscopic formulation of the interacting boson model for reflection asymmetric nuclei

  Kosuke Nomura

  International Journal of Modern Physics E 2340001 - 2340001 0218-3013 2023/03/08 [Refereed][Invited]
   

  Reflection asymmetric, octupole shapes in nuclei are a prominent aspect of nuclear structure, and have been recurrently studied over the decades. Recent experiments using radioactive-ion beams have provided evidence for stable octupole shapes. A variety of nuclear models have been employed for the related theoretical analyses. We review recent studies on the nuclear octupole shapes and collective excitations within the interacting boson model. A special focus is placed on the microscopic formulation of this model by using the mean-field method that is based on the framework of nuclear density functional theory. As an illustrative example, a stable octupole deformation, and a shape phase transition as a function of nucleon number that involves both quadrupole and octupole degrees of freedom are shown to occur in light actinides. Systematic spectroscopic studies indicate enhancement of the octupole collectivity in a wide mass region. Couplings between the octupole and additional degrees of freedom are incorporated in a microscopic manner in the boson system, and shown to play a crucial role in the description of the related intriguing nuclear structure phenomena such as the shape coexistence.
• Stability of the manifold boundary approximation method for reductions of nuclear structure models

  M. Imbrišak, K. Nomura

  Physical Review C 107 (3) 034304 - 034304 2469-9985 2023/03/07 [Refereed]
  
• Investigation of γ softness: Lifetime measurements in Ru104,106

  A. Esmaylzadeh, A. Blazhev, K. Nomura, J. Jolie, M. Beckers, C. Fransen, R.-B. Gerst, A. Harter, V. Karayonchev, L. Knafla, M. Ley, F. von Spee

  Physical Review C 106 (6) 064323-1 - 064323-13 2469-9985 2022/12/21 [Refereed]
  
• Overview of Seniority Isomers

  Bhoomika Maheshwari, Kosuke Nomura

  Symmetry 14 (12) 2680 - 2680 2022/12/18 [Refereed]
   

  Nuclear isomers are the metastable excited states of nuclei. The isomers can be categorized into a few classes including spin, seniority, K, shape and fission isomers depending upon the hindrance mechanisms. In this paper, we aim to present an overview of seniority isomers, which is a category related to the seniority quantum number. The discussion is mainly based on the concepts of seniority and generalized seniority. Various aspects of seniority isomers and their whereabouts have been covered along with the situations where seniority mixing prevents the isomerism.
• Collective-model description of shape coexistence and intruder states in cadmium isotopes based on a relativistic energy density functional

  K. Nomura, K. E. Karakatsanis

  Physical Review C 106 (6) 064317-1 - 064317-10 2469-9985 2022/12/15 [Refereed]
  
• Simultaneous description of β decay and low-lying structure of neutron-rich even- and odd-mass Rh and Pd nuclei

  K. Nomura, L. Lotina, R. Rodríguez-Guzmán, L. M. Robledo

  Physical Review C 106 (6) 064304-1 - 064304-17 2469-9985 2022/12/07 [Refereed]
  
• Effect of configuration mixing on quadrupole and octupole collective states of transitional nuclei

  Kosuke Nomura

  Physical Review C 106 (2) 024330-1 - 024330-13 2469-9985 2022/08/26 [Refereed]
  
• Signatures of shape phase transitions in krypton isotopes based on relativistic energy density functionals

  K. E. Karakatsanis, K. Nomura

  Physical Review C 105 (6) 064310-1 - 064310-14 2469-9985 2022/06/23 [Refereed]
  
• Octupole correlations in collective excitations of neutron-rich N≈56 nuclei

  Kosuke Nomura

  Physical Review C 105 (5) 054318  2469-9985 2022/05/27 [Refereed]
  
• β decay and evolution of low-lying structure in Ge and As nuclei

  Kosuke Nomura

  Physical Review C 105 (4) 2469-9985 2022/04/08 [Refereed]
  
• Two-neutrino double- β decay in the mapped interacting boson model

  Kosuke Nomura

  Physical Review C 105 (4) 2469-9985 2022/04/04 [Refereed]
  
• Questioning the wobbling interpretation of low-spin bands in γ -soft nuclei within the interacting boson-fermion model

  K. Nomura, C. M. Petrache

  Physical Review C 105 (2) 2469-9985 2022/02/18
• Linking Partial Dynamical Symmetry to Nuclear Energy Density Functional

  A. Leviatan, N. Gavrielov, K. Nomura

  Bulgarian Journal of Physics 49 (1) 067 - 077 1310-0157 2022/02/11 [Refereed]
  
• γ-ray spectroscopy of low-lying yrast and non-yrast states in neutron-rich Kr94,95,96

  R.-B. Gerst, A. Blazhev, K. Moschner, P. Doornenbal, A. Obertelli, K. Nomura, J.-P. Ebran, S. Hilaire, J. Libert, G. Authelet, H. Baba, D. Calvet, F. Château, S. Chen, A. Corsi, A. Delbart, J.-M. Gheller, A. Giganon, A. Gillibert, V. Lapoux, T. Motobayashi, M. Niikura, N. Paul, J.-Y. Roussé, H. Sakurai, C. Santamaria, D. Steppenbeck, R. Taniuchi, T. Uesaka, T. Ando, T. Arici, F. Browne, A. M. Bruce, R. Caroll, L. X. Chung, M. L. Cortés, M. Dewald, B. Ding, F. Flavigny, S. Franchoo, M. Górska, A. Gottardo, J. Jolie, A. Jungclaus, J. Lee, M. Lettmann, B. D. Linh, J. Liu, Z. Liu, C. Lizarazo, S. Momiyama, S. Nagamine, N. Nakatsuka, C. R. Nita, C. Nobs, L. Olivier, R. Orlandi, Z. Patel, Zs. Podolyák, M. Rudigier, T. Saito, C. Shand, P.-A. Söderström, I. Stefan, V. Vaquero, V. Werner, K. Wimmer, Z. Xu

  Physical Review C 105 (2) 2469-9985 2022/02/03 [Refereed]
  
• Quadrupole-octupole collectivity in the Xe, Ba, Ce and Nd isotopic chains described with mean field and beyond approaches

  R Rodríguez-Guzmán, L M Robledo, K Nomura, N Cruz Hernandez

  Journal of Physics G: Nuclear and Particle Physics 2022/01/01 [Refereed]
  
• Lifetime measurements to investigate γ softness and shape coexistence in Mo102

  A. Esmaylzadeh, V. Karayonchev, K. Nomura, J. Jolie, M. Beckers, A. Blazhev, A. Dewald, C. Fransen, R.-B. Gerst, G. Häfner, A. Harter, L. Knafla, M. Ley, L. M. Robledo, R. Rodríguez-Guzmán, M. Rudigier

  Physical Review C 104 (6) 2469-9985 2021/12/15 [Refereed]
  
• Quadrupole-octupole coupling and the evolution of collectivity in neutron-deficient Xe, Ba, Ce, and Nd isotopes

  K. Nomura, R. Rodríguez-Guzmán, L. M. Robledo

  Physical Review C 104 (5) 2469-9985 2021/11/29 [Refereed]
  
• Evolution of octupole deformation and collectivity in neutron-rich lanthanides

  K. Nomura, R. Rodríguez-Guzmán, L. M. Robledo, J. E. García-Ramos, N. C. Hernández

  Physical Review C 104 (4) 2469-9985 2021/10/21 [Refereed]
  
• Partial dynamical symmetry from energy density functionals

  K. Nomura, N. Gavrielov, A. Leviatan

  Physical Review C 104 (4) 2469-9985 2021/10/14 [Refereed]
  
• Interplay between pairing and triaxial shape degrees of freedom in Os and Pt nuclei

  K. Nomura, D. Vretenar, Z. P. Li, J. Xiang

  Physical Review C 104 (2) 2469-9985 2021/08/19 [Refereed]
  
• Coupling of pairing and triaxial shape vibrations in collective states of γ -soft nuclei

  K. Nomura, D. Vretenar, Z. P. Li, J. Xiang

  Physical Review C 103 (5) 2469-9985 2021/05/25 [Refereed]
  
• Microscopic description of octupole collective excitations near N=56 and N=88

  K. Nomura, L. Lotina, T. Nikšić, D. Vretenar

  Physical Review C 103 (5) 2469-9985 2021/05/03 [Refereed]
  
• Quadrupole-octupole coupling and the onset of octupole deformation in actinides

  K. Nomura, R. Rodríguez-Guzmán, L. M. Robledo, J. E. García-Ramos

  Physical Review C 103 (4) 2469-9985 2021/04/12 [Refereed]
  
• Octupole correlations in light actinides from the interacting boson model based on the Gogny energy density functional

  K. Nomura, R. Rodríguez-Guzmán, Y. M. Humadi, L. M. Robledo, J. E. García-Ramos

  Physical Review C 2020/12/28 [Refereed]
  
• Signatures of octupole shape phase transitions in radioactive nuclei

  Kosuke Nomura

  Journal of Physics: Conference Series 1643 012152 - 012152 2020/12
• Pairing vibrations in the interacting boson model based on density functional theory

  K. Nomura, D. Vretenar, Z. P. Li, J. Xiang

  Physical Review C 2020/11/10 [Refereed]
  
• Shape phase transitions in odd−A Zr isotopes

  K. Nomura, T. Nikšić, D. Vretenar

  Physical Review C 2020/09/10
• β decay of even- A nuclei within the interacting boson model with input based on nuclear density functional theory

  K. Nomura, R. Rodríguez-Guzmán, L. M. Robledo

  Physical Review C 2020/04/30
• Structure of odd-odd Cs isotopes within the interacting boson-fermion-fermion model based on the Gogny-D1M energy density functional

  K. Nomura, R. Rodríguez-Guzmán, L. M. Robledo

  Physical Review C 101 (1) 2020/01/08
• Beyond Mean-field Boson–Fermion Description of Odd Nuclei

  K. Nomura

  Acta Physica Polonica B Proceedings Supplement 13 (3) 457 - 457 2020 [Refereed]
  
• Lifetime measurements and shape coexistence in Sr97

  A. Esmaylzadeh, J.-M. R{\'{e } }gis, Y. H. Kim, U. Köster, J. Jolie, V. Karayonchev, L. Knafla, K. Nomura, L. M. Robledo, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n

  Physical Review C 100 (6) 2019/12/13
• Shape coexistence in Hg178

  C. Müller-Gatermann, A. Dewald, C. Fransen, K. Auranen, H. Badran, M. Beckers, A. Blazhev, T. Braunroth, D. M. Cullen, G. Fruet, A. Goldkuhle, T. Grahn, P. T. Greenlees, A. Herz{\'{a } },{\v{n } }, U. Jakobsson, D. Jenkins, J. Jolie, R. Julin, S. Juutinen, J. Konki, M. Leino, J. Litzinger, K. Nomura, J. Pakarinen, P. Peura, M. G. Procter, P. Rahkila, P. Ruotsalainen, M. S, zelius, J. Sar{\'{e } }n, C. Scholey, J. Sorri, S. Stolze, M. J. Taylor, J. Uusitalo, K. O. Zell

  Physical Review C 99 (5) 2019/05/21
• Spectroscopy of odd-odd nuclei within the interacting boson-fermion-fermion model based on the Gogny energy-density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C 99 (3) 2019/03/07
• Two-neutron transfer reactions and shape phase transitions in the microscopically formulated interacting boson model

  K. Nomura, Y. Zhang

  Physical Review C 99 (2) 2019/02/26
• Coexistence and evolution of shapes: mean-field-based interacting boson model

  Kosuke Nomura

  EPJ Web of Conferences 223 01046 - 01046 2019 

  A method of deriving the Hamiltonian of the interacting boson model, that is based on the microscopic framework of the nuclear energy density functional, is presented. The constrained self-consistent mean-field calculation with a given energy density functional provides potential energy surface within the relevant collective coordinates, which is subsequently mapped onto the expectation value of the interacting-boson Hamiltonian in the boson condensate state. This procedure completely determines the strength parameters of the IBM, and the diagonalization of the mapped Hamiltonian yields excitation spectra and transition rates for a given nucleus. Two recent applications of the method are discussed, that is, the descriptions of the intruder states in Cadmiumisotopes and the octupole correlations in neutron-rich odd-mass Barium isotopes.
• Beyond-mean-field Boson-fermion Description of Odd-mass Nuclei

  K. Nomura

  Nuclear Physics Review 35 (4) 499 - 504 2018/12 [Refereed]
  
• Structure of even-even cadmium isotopes from the beyond-mean-field interacting boson model

  K. Nomura, J. Jolie

  Physical Review C 98 (2) 2018/08/01
• Prolate-to-oblate shape phase transitions in neutron-rich odd-mass nuclei

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C 97 (6) 2018/06/20
• Description of neutron-rich odd-mass krypton isotopes within the interacting boson-fermion model based on the Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C 97 (6) 2018/06/18
• Signatures of octupole correlations in neutron-rich odd-mass barium isotopes

  K. Nomura, T. Nik{\v{s } }i{\'{c } }, D. Vretenar

  Physical Review C 97 (2) 2018/02/16
• Shape transitions in odd-mass γ -soft nuclei within the interacting boson-fermion model based on the Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C 96 (6) 2017/12/20
• Neutron-proton pairing and double- β decay in the interacting boson model

  P. Van Isacker, J. Engel, K. Nomura

  Physical Review C 96 (6) 2017/12/04
• Structure of krypton isotopes within the interacting boson model derived from the Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, Y. M. Humadi, L. M. Robledo, H. Abusara

  Physical Review C 96 (3) 2017/09/08
• Description of odd-mass nuclei within the interacting boson-fermion model based on the Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C American Physical Society 96 (1) 14314 - 14314 2469-9985 2017/07/21 

  Spectroscopic properties of odd-mass nuclei are studied within the framework of the interacting boson-fermion model (IBFM) with parameters based on the Hartree-Fock-Bogoliubov (HFB) approximation. The parametrization D1M of the Gogny energy density functional (EDF) was used at the mean-field level to obtain the deformation energy surfaces for the considered nuclei in terms of the quadrupole deformations (β,γ). In addition to the energy surfaces, both single-particle energies and occupation probabilities were used as a microscopic input for building the IBFM Hamiltonian. Only three strength parameters for the particle-boson-core coupling are fitted to experimental spectra. The IBFM Hamiltonian is then used to compute the energy spectra and electromagnetic transition rates for selected odd-mass Eu and Sm nuclei as well as for 195Pt and 195Au. A reasonable agreement with the available experimental data is obtained for the considered odd-mass nuclei.
• Shape-phase transitions in odd-mass γ -soft nuclei with mass A≈130

  K. Nomura, T. Nik{\v{s } }i{\'{c } }, D. Vretenar

  Physical Review C American Physical Society 96 (1) 14304 - 14304 2469-9985 2017/07/07 

  Quantum phase transitions between competing equilibrium shapes of nuclei with an odd number of nucleons are explored using a microscopic framework of nuclear energy density functionals and a fermion-boson coupling model. The boson Hamiltonian for the even-even core nucleus, as well as the spherical single-particle energies and occupation probabilities of unpaired nucleons, are completely determined by a constrained self-consistent mean-field calculation for a specific choice of the energy density functional and pairing interaction. Only the strength parameters of the particle-core coupling have to be adjusted to reproduce a few empirical low-energy spectroscopic properties of the corresponding odd-mass system. The model is applied to the odd-A Ba, Xe, La, and Cs isotopes with mass A≈130, for which the corresponding even-even Ba and Xe nuclei present a typical case of γ-soft nuclear potential. The theoretical results reproduce the experimental low-energy excitation spectra and electromagnetic properties, and confirm that a phase transition between nearly spherical and γ-soft nuclear shapes occurs also in the odd-A systems.
• Structural evolution in germanium and selenium nuclei within the mapped interacting boson model based on the Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C American Physical Society 95 (6) 64310 - 64310 2469-9985 2017/06/13 

  The shape transitions and shape coexistence in the Ge and Se isotopes are studied within the interacting boson model (IBM) with the microscopic input from a self-consistent mean-field calculation based on the Gogny-D1M energy density functional. The mean-field energy surface as a function of the quadrupole shape variables β and γ, obtained from the constrained Hartree-Fock-Bogoliubov method, is mapped onto the expectation value of the IBM Hamiltonian with configuration mixing in the boson condensate state. The resultant Hamiltonian is used to compute excitation energies and electromagnetic properties of the selected nuclei 66–94Ge and 68–96Se. Our calculation suggests that many nuclei exhibit γ softness. Coexistence between prolate and oblate shapes, as well as between spherical and γ-soft shapes, is also observed. The method provides a reasonable description of the observed systematics of the excitation energy of the low-lying energy levels and transition strengths for nuclei below the neutron shell closure N=50, and provides predictions on the spectroscopy of neutron-rich Ge and Se isotopes with 52≤N≤62, where data are scarce or not available.
• γ-ray spectroscopy of low-lying excited states and shape competition inOs194

  T. Daniel, S. Kisyov, P. H. Regan, N. Marginean, Zs. Podoly{\'{a } }k, R. Marginean, K. Nomura, M. Rudigier, R. Mihai, V. Werner, R. J. Carroll, L. A. Gurgi, A. Oprea, T. Berry, A. Serban, C. R. Nita, C. Sotty, R. Suvaila, A. Turturica, C. Costache, L. Stan, A. Olacel, M. Boromiza, S. Toma

  Physical Review C 95 (2) 2017/02/28
• Signatures of shape phase transitions in odd-mass nuclei

  K. Nomura, T. Nik{\v{s } }i{\'{c } }, D. Vretenar

  Physical Review C 94 (6) 2016/12/08
• Excited states and reduced transition probabilities in Os168

  T. Grahn, S. Stolze, D. T. Joss, R. D. Page, B. Say{\u{g } },{\i}, D. O{\textquotesingle}Donnell, M. Akmali, K. Andgren, L. Bianco, D. M. Cullen, A. Dewald, P. T. Greenlees, K. Heyde, H. Iwasaki, U. Jakobsson, P. Jones, D. S. Judson, R. Julin, S. Juutinen, S. Ketelhut, M. Leino, N. Lumley, P. J. R. Mason, O. Möller, K. Nomura, M. Nyman, A. Petts, P. Peura, N. Pietralla, Th. Pissulla, P. Rahkila, P. J. Sapple, J. Sar{\'{e } }n, C. Scholey, J. Simpson, J. Sorri, P. D. Stevenson, J. Uusitalo, H. V. Watkins, J. L. Wood

  Physical Review C 94 (4) 2016/10/28
• Structural evolution inA≈100nuclei within the mapped interacting boson model based on the Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C 94 (4) 044314  2016/10/17 [Refereed]
  
• Beyond-mean-field boson-fermion model for odd-mass nuclei

  K. Nomura, T. Nik{\v{s } }i{\'{c } }, D. Vretenar

  Physical Review C 93 (5) 2016/05/02
• Nuclear structure of 96,98Mo: Shape coexistence and mixed-symmetry states

  T. Thomas, V. Werner, J. Jolie, K. Nomura, T. Ahn, N. Cooper, H. Duckwitz, A. Fitzler, C. Fransen, A. Gade, M. Hinton, G. Ilie, K. Jessen, A. Linnemann, P. Petkov, N. Pietralla, D. Radeck

  Nuclear Physics A 947 203 - 233 2016/03
• Shape coexistence in the microscopically guided interacting boson model

  K Nomura, T Otsuka, P Van Isacker

  Journal of Physics G: Nuclear and Particle Physics 43 (2) 024008 - 024008 2016/02/01 [Refereed][Invited]
  
• Microscopic analysis of pear-shaped nuclei

  K. Nomura

  AIP Conference Proceedings 1681 040009  0094-243X 2015/10/15 [Refereed]
  
• Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C 92 (1) 0556-2813 2015/07/17 [Refereed]
  
• Advances in the Microscopic Study of the Interacting Boson Model

  Kosuke Nomura

  Proceedings of the Conference on Advances in Radioactive Isotope Science (ARIS2014) 2015/06/30
• Evolution ofE2transition strength in deformed hafnium isotopes from new measurements onHf172,Hf174, andHf176

  M. Rudigier, K. Nomura, M. Dannhoff, R-B. Gerst, J. Jolie, N. Saed-Samii, S. Stegemann, J-M. R{\'{e } }gis, L. M. Robledo, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, A. Blazhev, Ch. Fransen, N. Warr, K. O. Zell

  Physical Review C 91 (4) 0556-2813 2015/04/02 [Refereed]
  
• Microscopic and Algebraic Theory for Complex Nuclear Shapes and Dynamics

  K. Nomura

  Bulgarian Journal of Physics 42 344 - 353 2015 [Refereed]
  
• Microscopic analysis of quadrupole-octupole shape evolution

  Kosuke Nomura

  EPJ Web of Conferences 93 01007 - 01007 2015
• Microscopic description of octupole shape-phase transitions in light actinide and rare-earth nuclei

  K. Nomura, D. Vretenar, T. Nik{\v{s } }i{\'{c } }, Bing-Nan Lu

  Physical Review C 89 (2) 0556-2813 2014/02/24 [Refereed]
  
• Evidence for shape coexistence in98Mo

  T. Thomas, K. Nomura, V. Werner, T. Ahn, N. Cooper, H. Duckwitz, M. Hinton, G. Ilie, J. Jolie, P. Petkov, D. Radeck

  Physical Review C 88 (4) 2013/10/07
• Microscopic analysis of the octupole phase transition in Th isotopes

  K. Nomura, D. Vretenar, B.-N. Lu

  Physical Review C 88 (2) 2013/08/19
• Interacting boson model with energy density functionals

  K Nomura

  Journal of Physics: Conference Series 445 012015 - 012015 2190-5053 2013/07/03
• Shape evolution and the role of intruder configurations in Hg isotopes within the interacting boson model based on a Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo

  Physical Review C 87 (6) 2013/06/21
• INTERACTING BOSON MODEL FROM MEAN-FIELD THEORY: APPLICATION TO TRIAXIAL NUCLEI

  K. NOMURA

  Capture Gamma-Ray Spectroscopy and Related Topics 121 - 126 2013/05 [Refereed]
  
• Shape dynamics in neutron-rich Kr isotopes: Coulomb excitation of 92Kr, 94Kr and 96Kr

  M. Albers, K. Nomura, N. Warr, A. Blazhev, J. Jolie, D. Mücher, B. Bastin, C. Bauer, C. Bernards, L. Bettermann, V. Bildstein, J. Butterworth, M. Cappellazzo, J. Cederkäll, D. Cline, I. Darby, S. Das Gupta, J.M. Daugas, T. Davinson, H. De Witte, J. Diriken, D. Filipescu, E. Fiori, C. Fransen, L.P. Gaffney, G. Georgiev, R. Gernhäuser, M. Hackstein, S. Heinze, H. Hess, M. Huyse, D. Jenkins, J. Konki, M. Kowalczyk, T. Kröll, R. Krücken, J. Litzinger, R. Lutter, N. Marginean, C. Mihai, K. Moschner, P. Napiorkowski, B.S. Nara Singh, K. Nowak, J. Pakarinen, M. Pfeiffer, D. Radeck, P. Reiter, S. Rigby, L.M. Robledo, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, M. Rudigier, M. Scheck, M. Seidlitz, B. Siebeck, G.S. Simpson, P. Thöle, T. Thomas, J. Van de Walle, P. Van Duppen, M. Vermeulen, D. Voulot, R. Wadsworth, F. Wen, er, K. Wimmer, K.O. Zell, M. Zielinska

  Nuclear Physics A 899 1 - 28 2013/02
• Derivation of the Interacting Boson Model from mean-field theory

  Kosuke Nomura

  Nuclear Structure Problems 116 - 121 2012/12 [Refereed]
  
• Interacting boson model from energy density functionals: γ-softness and the related topics

  K. Nomura

  AIP Conference Proceedings 1491 170 - 173 0094-243X 2012/10/22 [Refereed]
  
• Interacting boson model from microscopic theory

  K. Nomura

  AIP Conference Proceedings 1488 69 - 76 0094-243X 2012/10 [Refereed]
  
• Shape coexistence in lead isotopes in the interacting boson model with a Gogny energy density functional

  K. Nomura, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo, N. Shimizu

  Physical Review C 86 (3) 2012/09/17
• Shape phase transitions in the interacting boson model: Phenomenological versus microscopic descriptions

  J. Kotila, K. Nomura, L. Guo, N. Shimizu, T. Otsuka

  Physical Review C 85 (5) 0556-2813 2012/05/09 

  We investigate the shape phase transition in even-even Gd-64 and Dy-66 isotopes within the proton-neutron interacting boson model (IBM-2). The parameters of the IBM-2 Hamiltonian are fixed in two different ways: the usual phenomenological fitting calculation and the mapping of the constrained self-consistent mean-field calculation with a Skyrme energy density functional onto the appropriate boson system. Notable differences are found between the energy surfaces for the phenomenological and the mapped IBM-2. Key quantities for the collective structural evolution, including level energies, B(E2) values, quadrupole moments, and the two-neutron separation energies, are analyzed in comparison to the experimental data. We show that the transition in these quantities occurs rapidly with the neutron number in the IBM-2 phenomenology but is somewhat smeared out in the mapped IBM-2. The differences in the measurable quantities are consistent with what is suggested by the energy-surface analysis.
• Robust Regularity inγ-Soft Nuclei and Its Microscopic Realization

  K. Nomura, N. Shimizu, D. Vretenar, T. Nik{\v{s } }i{\'{c } }, T. Otsuka

  Physical Review Letters 108 (13) 2012/03/30
• Evidence for a Smooth Onset of Deformation in the Neutron-Rich Kr Isotopes

  M. Albers, N. Warr, K. Nomura, A. Blazhev, J. Jolie, D. Mücher, B. Bastin, C. Bauer, C. Bernards, L. Bettermann, V. Bildstein, J. Butterworth, M. Cappellazzo, J. Cederkäll, D. Cline, I. Darby, S. Das Gupta, J. M. Daugas, T. Davinson, H. De Witte, J. Diriken, D. Filipescu, E. Fiori, C. Fransen, L. P. Gaffney, G. Georgiev, R. Gernhäuser, M. Hackstein, S. Heinze, H. Hess, M. Huyse, D. Jenkins, J. Konki, M. Kowalczyk, T. Kröll, R. Krücken, J. Litzinger, R. Lutter, N. Marginean, C. Mihai, K. Moschner, P. Napiorkowski, B. S. Nara Singh, K. Nowak, T. Otsuka, J. Pakarinen, M. Pfeiffer, D. Radeck, P. Reiter, S. Rigby, L. M. Robledo, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, M. Rudigier, P. Sarriguren, M. Scheck, M. Seidlitz, B. Siebeck, G. Simpson, P. Thöle, T. Thomas, J. Van de Walle, P. Van Duppen, M. Vermeulen, D. Voulot, R. Wadsworth, F. Wen, er, K. Wimmer, K. O. Zell, M. Zielinska

  Physical Review Letters 108 (6) 2012/02/10
• Collective structural evolution in neutron-rich Yb, Hf, W, Os, and Pt isotopes

  K. Nomura, T. Otsuka, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo, P. Sarriguren

  Physical Review C 84 (5) 2011/11/21
• Quadrupole collective dynamics from energy density functionals: Collective Hamiltonian and the interacting boson model

  K. Nomura, T. Nik{\v{s } }i{\'{c } }, T. Otsuka, N. Shimizu, D. Vretenar

  Physical Review C 84 (1) 2011/07/06
• Spectroscopic calculations of the low-lying structure in exotic Os and W isotopes

  K. Nomura, T. Otsuka, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo, P. Sarriguren, P. H. Regan, P. D. Stevenson, Zs. Podoly{\'{a } }k

  Physical Review C 83 (5) 2011/05/09
• Microscopic formulation of the interacting boson model for rotational nuclei (vol 83, 041302, 2011)

  Kosuke Nomura, Takaharu Otsuka, Noritaka Shimizu, Lu Guo

  PHYSICAL REVIEW C 83 (5) 0556-2813 2011/05 [Refereed][Not invited]
  
• Microscopic derivation of IBM and structural evolution in nuclei

  Nomura, Kosuke

  AIP Conference Proceedings 0094-243X 2011/05 [Refereed]
   

  A Hamiltonian of the interacting boson model (IBM) is derived based on the mean-field calculations with nuclear energy density functionals (EDFs). The multi-nucleon dynamics of the surface deformation is simulated in terms of the boson degrees of freedom. The interaction strengths of the IBM Hamiltonian are determined by mapping the potential energy surfaces (PESs) of a given EDF with quadrupole degrees of freedom onto the corresponding PES of IBM. A fermion-to-boson mapping for a rotational nucleus is discussed in terms of the rotational response, which reflects a specific time-dependent feature. Ground-state correlation energy is evaluated as a signature of structural evolution. Some examples resulting from the present spectroscopic calculations are shown for neutron-rich Pt, Os and W isotopes including exotic ones.
• Microscopic formulation of the interacting boson model for rotational nuclei

  Kosuke Nomura, Takaharu Otsuka, Noritaka Shimizu, Lu Guo

  Physical Review C 83 (4) 0556-2813 2011/04/25 [Refereed]
   

  We propose a novel formulation of the interacting boson model (IBM) for rotational nuclei with axially symmetric, strong deformation. The intrinsic structure represented by the potential-energy surface (PES) of a given multinucleon system has a certain similarity to that of the corresponding multiboson system. Based on this feature, one can derive an appropriate boson Hamiltonian, as already reported. This prescription, however, has a major difficulty in the rotational spectra of strongly deformed nuclei: the bosonic moment of inertia is significantly smaller than the corresponding nucleonic one. We present that this difficulty originates in the difference between the rotational response of a nucleon system and that of the corresponding boson system, and could arise even if the PESs of the two systems were identical. We further suggest that the problem can be solved by implementing the (L) over cap center dot(L) over cap term into the IBM Hamiltonian, with the coupling constant derived from the cranking approach of Skyrme mean-field models. The validity of the method is confirmed for rare-earth and actinoid nuclei, as their experimental rotational yrast bands are reproduced nicely.
• Structural evolution in Pt isotopes with the interacting boson model Hamiltonian derived from the Gogny energy density functional

  K. Nomura, T. Otsuka, R. Rodr{\'{\i } }guez-Guzm{\'{a } }n, L. M. Robledo, P. Sarriguren

  Physical Review C 83 (1) 2011/01/25 [Refereed]
  
• Derivation of IBM Hamiltonian for deformed nuclei

  Kosuke Nomura, Takaharu Otsuka, Noritaka Shimizu, Lu Guo

  Journal of Physics: Conference Series 267 012050 - 012050 1742-6588 2011/01/01 

  A Hamiltonian of the Interacting Boson Model (IBM) is determined microscopically starting from the mean-field calculation. The potential energy surface (PES) by the Skyrme mean-field method is mapped onto the PES of the IBM to yield the interaction strengths of the IBM Hamiltonian, by which levels and wave functions of excited states are calculated with good angular momentum and the particle number. The response of the rotating nucleon system is mapped onto the corresponding boson system in order to determine the coefficient of the rotational kinetic-like (L) over cap . (L) over cap term microscopically. By the present method, not only the three dynamical symmetries of IBM but also the recently proposed critical-point symmetries of shape-phase transitions are well reproduced. In particular, the experimental rotational band of the SU(3) nucleus in Sm isotopic chain is reproduced quite nicely. We also point out the quantum fluctuation effect on the binding energies, which is included by the diagonalization of the IBM Hamiltonian determined by the comparison to the Skyrme PES. Systematic results for spectra for Os isotopes are also presented.
• Formulating the interacting boson model by mean-field methods

  Kosuke Nomura, Noritaka Shimizu, Takaharu Otsuka

  Physical Review C 81 (4) 0556-2813 2010/04/12 [Refereed]
   

  The interacting boson model (IBM) Hamiltonian is determined microscopically for general cases of low-lying quadrupole collectivity. Under the assumption that the multinucleon-induced surface deformations, which reflect nuclear forces and the Pauli principle, can be simulated by bosons, the interaction strengths of the IBM Hamiltonian are derived by mapping the potential energy surface of the mean-field model with Skyrme force onto the corresponding one of the IBM. These interaction strengths turn out to change gradually as functions of valence nucleon numbers. The energy eigenvalues and the wave functions are calculated with the exact treatment of the particle number and the angular momentum. We demonstrate how well the method works by taking Sm isotopes as an example, where a typical spherical-deformed shape-phase transition is reproduced successfully. We show that the physically relevant IBM interaction strengths can be determined unambiguously by the use of wavelet analysis. In addition, by the diagonalization of the boson Hamiltonian, quantum-mechanical correlation effects can be included in the eigenenergies, by which the basic properties of these nuclei are properly reproduced. The present method is applied to several other isotopic chains, Ba, Xe, Ru, Pd, W, and Os, in comparison to the experimental data. We point out the relevance of our results to the recently proposed critical-point symmetries. The predicted spectra and the B(E2) ratios are presented for heavy neutron-rich exotic nuclei in experimentally unexplored regions such as the right-lower corner of Pb-208 on the nuclear chart.
• Mean-Field Derivation of the Interacting Boson Model Hamiltonian and Exotic Nuclei (vol 101, art no 142501, 2008)

  Kosuke Nomura, Noritaka Shimizu, Takaharu Otsuka

  PHYSICAL REVIEW LETTERS 102 (6) 0031-9007 2009/02 [Refereed][Not invited]
  
• NEW FORMULATION OF INTERACTING BOSON MODEL AND HEAVY EXOTIC NUCLEI

  K. Nomura, N. Shimizu, T. Otsuka

  Acta Physica Polônia B 40 (3) 603 - 606 2009 [Refereed]
  
• New Microscopic Derivation of the Interacting Boson Model and Its Applications to Exotic Nuclei

  K. Nomura, N. Shimizu, T. Otsuka

  AIP Conference Proceedings 2009 [Not refereed]
  
• New Microscopic foundation of Interacting Boson Model and collectivities in exotic nuclei

  K. Nomura, N. Shimizu, T. Otsuka

  AIP Conference Proceedings 2009 [Not refereed]
  
• Mean-Field Derivation of the Interacting Boson Model Hamiltonian and Exotic Nuclei

  Kosuke Nomura, Noritaka Shimizu, Takaharu Otsuka

  Physical Review Letters 101 (14) 0031-9007 2008/09/29 [Refereed]
  

MISC

• 24pZF-14 Low-lying collective states of heavy unstable nuclei

  Nomura K., Otsuka T., Shimizu N.  Meeting abstracts of the Physical Society of Japan  63-  (1)  81  -81  2008/02/29
• 22pZD-12 Shape phase transitions and critical point symmetries in neutron-rich nuclei

  Nomura Kosuke, Otsuka Takaharu, Shimizu Noritaka  Meeting abstracts of the Physical Society of Japan  62-  (2)  86  -86  2007/08/21

Books etc

• Chirality and Wobbling in Atomic Nuclei

  Kosuke Nomura (ContributorChapter 11)
  CRC Press 2024/12 (ISBN: 9781032691282)
• Interacting boson model from energy density functionals

  Nomura, Kosuke (Single work)
  Springer 2013 (ISBN: 9784431542339) xiii, 188 p.

Teaching Experience

Quantum Mechanics Exercise IQuantum Mechanics Exercise I Hokkaido University
Quantum Mechanics IQuantum Mechanics I Hokkaido University
Physics IIPhysics II Hokkaido University
Introduction to Modern PhysicsIntroduction to Modern Physics Hokkaido University
Nuclear Physics INuclear Physics I Hokkaido University
Nuclear PhysicsNuclear Physics Hokkaido University
Physics IPhysics I Hokkaido University
Numerical Methods and Mathematical ModelingsNumerical Methods and Mathematical Modelings Department of Physics, Faculty of Science, University of Zagreb
Theoretical Nuclear StructureTheoretical Nuclear Structure Department of Physics, Faculty of Science, University of Zagreb
Nuclear StructureNuclear Structure Department of Physics, Faculty of Science, University of Zagreb

Association Memberships

• European Physical Society   American Physical Society   Japanese Physical Society   

Research Projects

• Exotic Nuclear Structure and Dynamics

  Croatian Ministry of Science and Education, Croatian Science Foundation, and Swiss Federal Institute of Technology in Lausanne：Tenure-Track Pilot Programme

  Date (from‐to) : 2019/05 -2023/02 

  Author : Kosuke Nomura
• Uncertainty Quantification within the Nuclear Energy Density Functional Framework

  Croatian Science Foundation：

  Date (from‐to) : 2019/05 -2022
• 重い不安定核構造の理論研究

  Ministry of Education, Culture, Sports, Science and Technology：Excellent Young Researcher

  Date (from‐to) : 2018/04 -2020/03 

  Author : 野村昂亮
• QuantiXLie Center of Excellence

  Croatian government and European Union：

  Date (from‐to) : 2019/05
• 原子核の集団運動とエキゾチック核構造に関する理論的研究

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows

  Date (from‐to) : 2016/04 -2018/03 

  Author : 野村 昂亮

   

  今年度も前年度に引き続き、核子多体系の微視的理論である密度汎関数理論DFTに基づいた相互作用するボソン模型IBMの枠組みにおいて、原子核の集団励起を記述する研究を行った。今年度は先ず、DFT平均場計算からIBMハミルトニアンを導き、不安定核ビームを用いた実験研究において重要な、中性子過剰Ge, Se, Kr同位体の分光学的性質を記述した。特に、核子数の変化に伴う原子核形状と励起状態の遷移、いわゆる量子相転移と、異なる変形状態の共存（変形共存）状態を系統的に調べ、それらを特徴付ける励起状態エネルギーや電磁遷移などの物理量を計算した。理論的予言も行い、将来の不安定核実験のための重要な指針となりうる。さらに、前年度から継続して、この方法を奇核（陽子数または中性子が奇数）に拡張する研究にも取り組んだ。具体的には、偶偶核（陽子数、中性子数ともに偶数）をコアとしてそれに単一核子の自由度を加え、両者の間の相互作用をDFT計算に基づいて決定する。今年度は、Ba, Xeなどの、偶偶核コアが非軸対称変形した奇核の分光学的性質、特に量子相転移の秩序変数と考えられるいくつかの物理量を計算した。奇核構造の理解はベータ崩壊などの基本的な崩壊過程の記述にも不可欠である。近年、奇核の励起状態に関する多くの実験データが生み出されている一方、それらの微視的かつ系統的な記述は、特に中重核領域では理論的に非常に困難である。本研究で開発した手法は、中重領域の奇核構造への有力なアプローチといえる。それとは独立に、２重ベータ崩壊の研究も行った。対相関基底を用いた殻模型空間からアイソスピン自由度を考慮したボソン模型空間への写像によって、pf殻領域の原子核のボソンハミルトニアンと２重ベータ崩壊演算子を構築し、同崩壊過程の核行列要素を計算した。特に、ボソン模型における中性子陽子対の重要性を調べた。
• Microscopic and Algebraic Theory of Nuclei under Extreme Conditions

  European Commission：Seventh Framework Programme Marie-Curie Actions

  Date (from‐to) : 2013/09 -2015/08 

  Author : Kosuke Nomura
• Unified description of nuclear collective motion and the structure of exotic nuclei

  Japan Society for the Promotion of Science：海外特別研究員

  Date (from‐to) : 2012/04 -2013/08 

  Author : 野村昂亮
• 不安定核の集団運動に関する理論的研究

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows

  Date (from‐to) : 2009/04 -2012/03 

  Author : 野村 昂亮

   

  平均場理論と相互作用するボソン模型(IBM)の関連性という観点から、中重核の4重極集団運動を研究した。平均場理論では原子核の内部固有状態の物理量を計算できるが、励起状態のエネルギーと波動関数を計算するのは一般に難しい。一方IBMは励起状態の物理量をうまく記述できるが現象論的である。そこで、平均場理論から出発してIBMハミルトニアンを導く方法を近年開発した.4重極集団運動に関わる相互作用強度は、核子系からIBM系へのポテンシャルエネルギー面の写像によって導出する。まず、有限レンジのGogny型密度汎関数を用いて、白金近傍の広い範囲の重い原子核に適用した結果、実験で示唆される、4重極変形した原子核の持つ対称性とそれらの間の遷移「形状相転移」をほぼ再現した。さらに、回転に対する核子系のレスポンスをIBM系に写像する方法を考察した。従来のIBMでは現象論的にしか扱われなかった回転の質量:項(LL項)に注目して、平均場理論とIBMの両方でクランキング模型を用いて慣性モーメントを計算し、両者で等しくなるようにLL項のパラメータの値を微視的に決定した。強く軸対称変形した原子核においてイラスト状態のエネルギーを正確に再現することが出来た。相対論的平均場模型(RMF)の有効相互作用に基づいて、集団運動ハミルトニアンとIBMのハミルトニアンを導き、両者の励起状態の性質を比べ、前者における質量項の扱いや後者でのボソン三体力の必要性など、問題点を明らかにした。非相対論的なSkyrme力やRMFの相互作用などの微視的な自由度から出発して非軸対称変形した原子核の構造を調べた。ほぼ全ての非軸対称核は、従来知られてきたガンマ不安定な描像でもrigid triaxialの描像のどちらでもなくちょうどその中間であるという、経験的に知られた系統的性質を再現した。また、この性質を説明するのにボソンの三体力をIBMに導入する必要がある事を示した。

Media Coverage

• INNOVATION BOOST FOR CROATIA

  Date : 2020/03

  Writer: Other than myself

  Publisher, broadcasting station: SDC magazine One World

  Program, newspaper magazine: SDC magazine One World

  Internet
• EPFL News - A partnership to boost researchers' career prospects in Croatia

  Date : 2020/01

  Writer: Other than myself

  Publisher, broadcasting station: EPFL, Switzerland

  Internet
• ZNANSTVENICI OD MILIJUN EURA Istražuju životinje hrvatskog podzemlja, rudarenje promjenjivog neba i dinamiku egzotičnih atomskih jezgara

  Date : 2019/11/25

  Writer: Other than myself

  Program, newspaper magazine: Jutarnji list

  Paper
• 原子核の「歪(いびつ)な」変形の謎を解明

  Date : 2012/07

  Writer: Myself

  Program, newspaper magazine: 東京大学理学部ニュース

  Pr

Academic Contribution

• Progress of Theoretical and Experimental Physics

  Date (from-to) :2016/05-Today

  Role: Peer review

  Type: Peer review etc
• Physical Review Letters

  Date (from-to) :2015/12-Today

  Role: Peer review

  Type: Peer review etc
• Journal of Physics G: Nuclear and Particle Physics

  Date (from-to) :2015/10-Today

  Role: Peer review

  Type: Peer review etc
• Physics Letters B

  Date (from-to) :2015/06-Today

  Role: Peer review

  Type: Peer review etc
• Physical Review C

  Date (from-to) :2014/02-Today

  Role: Peer review

  Type: Peer review etc
• 10th International Workshop on Quantum Phase Transitions in Nuclei and Many-Body Systems

  Date (from-to) :2022/07/10-2022/07/15

  Role: Planning etc

  Type: Academic society etc

  Organizer, responsible person: University of Zagreb, Croatia, and Hebrew University, Israel
• National Fund for Scientific and Technological Development (FONDECYT)

  Date (from-to) :2018/11

  Role: Review

  Type: Review

  Organizer, responsible person: Chilean National Commission for Scientific and Technological Research (CONICYT)