Faculty of Science and Technology

Takayanagi Kazuo

  (高柳 和雄)

Profile Information

Affiliation
Professor, Graduate School of Science and Technology, Master's (Doctoral) Program in Science and Technology, Sophia University
Degree
理学士(東京大学)
理学修士(東京大学)
理学博士(東京大学)

Researcher number
30183859
J-GLOBAL ID
200901012910384968
researchmap Member ID
1000306056

(Subject of research)
Study on effective interactions batween electrons
Theoretical study of quantum dots
Theoretical study of metal clusters


Papers

 61
  • Kazuo Takayanagi, Mao Kurino
    Progress of Theoretical and Experimental Physics, 2023(7), Jun 14, 2023  Peer-reviewed
    Abstract We present the generalized optical theorem and its applications with special emphasis on the roles of bound states. First, we prove the theorem which gives a necessary and sufficient condition for a function $\langle {\boldsymbol {k } }^{\prime } | T | {\boldsymbol {k } } \rangle$ of two variables ${\boldsymbol {k } }^{\prime }$ and ${\boldsymbol {k } }$ to be physically acceptable as a half-on-shell T-matrix, i.e., to have an underlying Hermitian potential V. Secondly, using the theorem, we construct a scattering theory starting from a physically acceptable half-on-shell T-matrix $\langle {\boldsymbol {k } }^{\prime } | T | {\boldsymbol {k } } \rangle$, which in turn introduces a very useful classification scheme of Hermitian potentials. In the end, as an application of our theory, we present the most general solution of the inverse scattering problem with numerical examples.
  • Naofumi Tsunoda, Takaharu Otsuka, Kazuo Takayanagi, Noritaka Shimizu, Toshio Suzuki, Yutaka Utsuno, Sota Yoshida, Hideki Ueno
    Nature, 587(7832) 66-71, Nov 5, 2020  Peer-reviewed
    Atomic nuclei are composed of a certain number of protons Z and neutrons N. A natural question is how large Z and N can be. The study of superheavy elements explores the large Z limit(1,2), and we are still looking for a comprehensive theoretical explanation of the largest possible N for a given Z-the existence limit for the neutron-rich isotopes of a given atomic species, known as the neutron dripline(3). The neutron dripline of oxygen (Z = 8) can be understood theoretically as the result of single nucleons filling single-particle orbits confined by a mean potential, and experiments confirm this interpretation. However, recent experiments on heavier elements are at odds with this description. Here we show that the neutron dripline from fluorine (Z = 9) to magnesium (Z = 12) can be predicted using a mechanism that goes beyond the single-particle picture: as the number of neutrons increases, the nuclear shape assumes an increasingly ellipsoidal deformation, leading to a higher binding energy. The saturation of this effect (when the nucleus cannot be further deformed) yields the neutron dripline: beyond this maximum N, the isotope is unbound and further neutrons 'drip' out when added. Our calculations are based on a recently developed effective nucleon-nucleon interaction(4), for which large-scale eigenvalue problems are solved using configuration-interaction simulations. The results obtained show good agreement with experiments, even for excitation energies of low-lying states, up to the nucleus of magnesium-40 (which has 28 neutrons). The proposed mechanism for the formation of the neutron dripline has the potential to stimulate further thinking in the field towards explaining nucleosynthesis with neutron-rich nuclei.A mechanistic explanation for the origin of the neutron dripline shows that nuclei accommodate the addition of neutrons by becoming increasingly ellipsoidal, up to a maximum number of neutrons, reconciling theory and experiments.
  • Kazuo Takayanagi
    Annals of Physics, 415 168119(1)-168119(43), Jan 26, 2020  Peer-reviewed
  • Asumi Taniguchi, Kazuo Takayanagi
    JPS Conference Proceedings, 23 013010(1)-013010(4), Dec 27, 2018  Peer-reviewed
  • Kazuo Takayanagi
    JPS Conference Proceedings, 23 012004(1)-012004(6), Dec 27, 2018  Peer-reviewed

Misc.

 2

Books and Other Publications

 2

Professional Memberships

 1

Research Projects

 8

Other

 1
  • Apr, 2003 - Mar, 2008
    学部の2年生に、物理数学の基本的な概念とその応用を講義してきた。ここでは、上智大学の1年次に何を学んできており、これからどのような概念が必要になるかを考えて講義を組み立ててきた。そのように選択された内容を、学生が興味を持って受講できるよう、一般的な「物理数学」の教科書に沿った講義ではなく、「上智大学の物理学科の物理数学」としての特色を出した講義になるように努力してきた。