## Associate Professor TAKEDA Shinji

### Faculty, Affiliation

Faculty of Mathematics and Physics, Institute of Science and Engineering

### College and School Educational Field

Division of Mathematical and Physical Science, Graduate School of Natural Science and Technology

Division of Mathematical and Physical Sciences, Graduate School of Natural Science and Technology

### Laboratory

Institute for Theoretical Physics TEL:076-264-5919 FAX:076-264-5741

### Academic Background

**【Academic background(Doctoral/Master's Degree)】**

University of Tsukuba Doctor Physics 200510 Completed**【Academic background(Bachelor's Degree)】**

University of Tsukuba Physics 200103**【Degree】**

Doctor of Science

### Career

Research Fellow in Humboldt University Computational Physics(2005/10/03-2008/08/31)

Research Fellow in Columbia University Physics Department(2008/09/01-2009/11/30)

### Year & Month of Birth

1978/08

### Academic Society

### Award

### Specialities

Particle/Nuclear/Cosmic ray/Astro physics

### Speciality Keywords

lattice gauge theory, quantum chromodynamics, tensor network

### Research Themes

#### Analysis of phase structure for finite temperature/density QCD

The universe 0.00001 second after the Big Bang was extremely hot and quarks and gluons were freely moving around; such a state is called quark-gluon plasma (QGP) state. As time goes, the universe was rapidly expanding while cooling down. Then, quarks and gluon were trapped in hadrons (proton and neutron); such a state is called hadron state which is rather close to our current universe. When changing the state from the QGP to the hadron state, a rapid change of state, that is, a phase transition is believed to occur. The properties, say the nature of transition and the temperature at which the transition took place, etc. are, however, determined by dynamics of the fundamental theory. Therefore to reveal them, one has to rely on solving the theory by first principle simulations or carrying out experiments which realize the Big Bang in a lab. My final goal is to extract the information of the transition by following the former method.

#### Application of tensor network to high energy physics

Lattice QCD simulations play an important role in the study of QCD where the non-perturbative effect is crucial such as the confinement. On the other hand, there are some unsolved problems, for example, the strong CP problem, providing the equation of state for neutron stars, etc. When attacking these problems, however, one encounters the sign-problem that hampers the Monte-Carlo simulation since the Boltzmann weight is complex for such systems. In fact, there are many attempts to solve the sign-problem within a framework of the Monte-Carlo simulation but we do not have a perfect and general solution at this moment. Recently, however, an interesting idea was proposed in the condensed matter physics. It is called tensor network method whose striking feature is that there is no sign-problem. My interest is to apply the method to high energy physics, study the unexplored systems and reveal their dynamics.

### Books

### Papers

- Tensor Renormalization Group Algorithms with Projective Truncation Method 未定 2018/09/24
- Tensor network study of two dimensional lattice ϕ4 theory 2018/12/01
- Continuum extrapolation of the critical endpoint in 4-flavor QCD with Wilson-Clover fermions 2018/12/04
- Tensor network formulation for two-dimensional lattice N=1 Wess-Zumino model Daisuke Kadoh, Yoshinobu Kuramashi, Yoshifumi Nakamura, Ryo Sakai, Shinji Takeda, Yusuke Yoshimura Journal of High Energy Physics 03 2018 141 2018/03/23
- Application of tensor network method to two dimensional lattice N=1 Wess-Zumino model Ryo Sakai, Daisuke Kadoh, Yoshinobu Kuramashi, Yoshifumi Nakamura, Shinji Takeda Yusuke Yoshimura EPJ Web Conf. 175 2018/03/26

- Tensor network analysis of critical coupling in two dimensional ϕ4 theory 2018/11/29
- Application of tensor network method to two dimensional lattice N=1 Wess-Zumino model Ryo Sakai, Daisuke Kadoh, Yoshinobu Kuramashi, Yoshifumi Nakamura, Shinji Takeda Yusuke Yoshimura EPJ Web Conf. 175 2018/03/26
- Calculation of fermionic Green functions with Grassmann higher-order tensor renormalization group Yusuke Yoshimura, Yoshinobu Kuramashi, Yoshifumi Nakamura, Shinji Takeda, and Ryo Sakai Physical Review D 97 054511 1 2018/03/22
- Loop-TNR analysis of CP(1) model with theta term Hikaru Kawauchi, Shinji Takeda EPJ Web Conf. 175 2018/03/26
- Critical point phase transition for finite temperature 3-flavor QCD with non-perturbatively O(a) improved Wilson fermions at Nt=10 Xiao-Yong Jin, Yoshinobu Kuramashi, Yoshifumi Nakamura, Shinji Takeda, and Akira Ukawa PHYSICAL REVIEW D 96 034523 1 2017/08/30
- Higher-order tensor renormalization group for relativistic fermion systems Sakai, Ryo, Shinji Takeda, Yusuke, Yoshimura Progress of Theoretical and Experimental Physics 6 063B07 2017/06/30
- Critical endline of the finite temperature phase transition for 2+1 flavor QCD around the SU(3)-flavor symmetric point Yoshinobu Kuramashi, Yoshifumi Nakamura, Shinji Takeda, Akira Ukawa PHYSICAL REVIEW D 94 114507 1 2016/12/09
- Tensor renormalization group analysis of CP(N-1) model Hikaru Kawauchi, Shinji Takeda PHYSICAL REVIEW D 93 114503 1 2016/06/06
- Lattice Study on quantum-mechanical dynamics of two-color QCD with six light flavors M. Hayakawa, K. Ishikawa, S. Takeda, N. Yamada PHYSICAL REVIEW D 88 094506 2013/07
- Running coupling constant and mass anomalous dimension of six-flavor SU(2) gauge theory M. Hayakawa, K. Ishikawa, S. Takeda, N. Yamada PHYSICAL REVIEW D 88 094504 2013/07
- Finite size scaling study of Nf=4 finite density QCD on the lattice Jin, Xiao-Yong;Kuramashi, Yoshinobu;Nakamura, Yoshifumi;Takeda, Shinji;Ukawa, Akira PHYSICAL REVIEW D 88 094508 2013/07
- Grassmann tensor renormalization group for the one-flavor lattice Gross–Neveu model with finite chemical potential Shinji Takeda, Yusuke, Yoshimura PTEP 4 043B01 2014/12
- Curvature of the critical line on the plane of quark chemical potential and pseudoscalar meson mass for three-flavor QCD Jin, Xiao-Yong;Kuramashi, Yoshinobu;Nakamura, Yoshifumi;Takeda, Shinji;Ukawa, Akira PHYSICAL REVIEW D 92 114511 1 2015/04
- Formulation of domain-wall fermions in the Schrodinger functional Takeda, Shinji PHYSICAL REVIEW D 87 114506 1 2013/06/11
- Critical endpoint of the finite temperature phase transition for three flavor QCD Jin, Xiao-Yong;Kuramashi, Yoshinobu;Nakamura, Yoshifumi;Takeda, Shinji;Ukawa, Akira PHYSICAL REVIEW D 91 014508 1 2015/01/01

### Conference Presentations

- Tensor network approach to quantum fieldtheories suffering from sign problem(conference：5th Joint Meeting of the APS Division of Nuclear Physics and JPS)(2018/10/23)
- Elementary Particle Physics and Tensor Networks(conference：Kanazawa U. & Kazan F.U. Joint Symposium on Physics)(2019/01/29)
- Phase structure of finite density QCD(conference：German-Japanese Seminar)(2013/11)
- Exploring QCD phase diagram by Wilson type fermions(conference：Lattice QCD at finite temperature and density)(2014/01)
- Tensor renormalization group approach to finite fermion density system(conference：10sor network workshop, Field 2x5 joint workshop on new algorithm for quantum many body)(2014/11)

- Curvature of critical line in mpi-mu plane for 3-flavor QCD(conference：CCS-BNL Lattice gauge theory 2015)(2015/03)

### Arts and Fieldwork

### Patent

### Theme to the desired joint research

### Grant-in-Aid for Scientific Research

○「テンソルネットワーク法による素粒子物理学の諸問題へのアプローチ」(2017-2020)

○「量子色力学の高密度領域へのアプローチ」(2011-2013)

○「有限温度・密度QCDの臨界点探索」(2014-2016)

○「量子色力学の相構造解析」(2011-2012)

### Classes (Bachelors)

○Exercise in Quantum Mechanics 1(2018)

○Selected Topics(2018)

○Exercise in Quantum Mechanics 2B(2018)

○Exercise in Quantum Mechanics 2A(2018)

○Computer Experiments 2(2018)

○Computational Physics B(2018)

○Computational Physics A(2018)

○Computational Physics B(2017)

○Computational Physics A(2017)

○Computer Experiments 2(2017)

○Introduction to Region-studies(2017)

○Exercise in Quantum Mechanics 1(2017)

○Exercise in Quantum Mechanics 2(2017)

○Introduction to Region-studies(2016)

○Computer Experiments 2(2016)

○Computational Physics(2016)

○Exercise in Quantum Mechanics 2(2016)

○Exercise in Quantum Mechanics 1(2016)

### Classes (Graduate Schools)

○Seminar B(2018)

○Special Lectures on Physics(2018)

○Theoretical Physics b(2018)

○Theoretical Physics a(2018)

○Theoretical Physics IIb(2018)

○Theoretical Physics IIa(2018)

○Introduction to Theoretical Physics b(2018)

○Exercise B(2018)

○Introduction to Theoretical Physics a(2018)

○Research Work B(2018)

○Seminar B(2017)

○Introduction to Theoretical Physics a(2017)

○Theoretical Physics IIb(2017)

○Theoretical Physics IIa(2017)

○Theoretical Physics Ib(2017)

○Exercise B(2017)

○Research Work B(2017)

○Introduction to Theoretical Physics b(2017)

○Theoretical Physics Ia(2017)

○Research Work B(2016)

○Seminar B(2016)

○Theoretical Physics Ib(2016)

○Theoretical Physics Ia(2016)

○Exercise B(2016)

○Introduction to Theoretical Physics a(2016)

○Theoretical Physics II(2016)

○Introduction to Theoretical Physics b(2016)