## Basic Information

### Major Professional Backgrounds

- 1991/04/01, 1996/03/31, Hitachi, Ltd., Researcher
- 1996/04/01, 1998/09/30, Tokyo Gakugei University, Faculty of Education, Lecturer
- 1998/10/01, 2004/04/30, Okayama University, Faculty of Science, Associate Professor
- 2004/05/01, 2005/03/31, Okayama University, Faculty of Science, Professor
- 2005/04/01, 2014/09/30, Okayama University, Professor
- 2014/10/01, Hiroshima University, Institute of Engineering, Professor
- 2018/12/01, Kyushu University, Faculty of Information Science and Electrical Engineering, Professor

### Academic Degrees

- Doctor of Science, HOKKAIDO UNIVERSITY
- Master of Science, HOKKAIDO UNIVERSITY

### Affiliated Academic Societies

- The Society for Industrial and Applied Mathematics
- The American Physical Society
- The International Association of Mathematical Physics
- The Japan Society of Applied Physics
- The Physical Society of Japan
- The Mathematical Society of Japan

## Educational Activity

### Course in Charge

- 2019, Undergraduate Education, 1Term, Applied Mathematics II
- 2019, Undergraduate Education, 2Term, Applied Mathematics III
- 2019, Undergraduate Education, 2Term, Fourier Analysis
- 2019, Graduate Education (Master's Program) , First Semester, Stochastic Differential Equations
- 2019, Graduate Education (Master's Program) , First Semester, Stochastic Differential Equations
- 2019, Graduate Education (Master's Program) , First Semester, Directed Study in System Cybernetics IA
- 2019, Graduate Education (Master's Program) , Second Semester, Directed Study in System Cybernetics IB
- 2019, Graduate Education (Master's Program) , First Semester, Seminar in System Cybernetics IA
- 2019, Graduate Education (Master's Program) , Second Semester, Seminar in System Cybernetics IB

## Research Activities

### Academic Papers

- A mathematical modeling of electron-phonon interaction for small wave numbers close to zero, EMS Series of Congress Reports, ``Functional Analysis and Operator Theory for Quantum Physics'', Pavel Exner Anniversary Volume, 373-400, 20170501
- A mathematical analysis of dressed photon in ground state of generalized quantum Rabi model using pair theory, Journal of Physics A: Mathematical and Theoretical, 50(18), 184003-1-184003-20, 20170405
- Duality between a dark state and a quasi-dark state, Annals of Physics (N.Y.), 377, 229-242, 20161229
- The Rabi model gives off a flavor of spontaneous SUSY breaking, Quantum Studies: Mathematics and Foundations, 2(4), 379-388, 201512
- Absence of energy level crossing for the ground state energy of the Rabi model, Communications on Stochastic Analysis, 8(4), 551-560, 201412
- Spin-boson model through a Poisson-driven stochastic process, MATHEMATISCHE ZEITSCHRIFT, 277(3-4), 1165-1198, 201408
- A mathematical aspect of a tunnel-junction for spintronic qubit, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 417(2), 856-872, 201409
- One-dimensional tunnel-junction formula for the Schrodinger particle, SIAM JOURNAL ON APPLIED MATHEMATICS, 73(6), 2247-2261, 2013
- Boundary Conditions in One-dimensional Tunneling Junction, JOURNAL OF PHYSICS: Conference Series, 302(1), 0124044-1-0124044-4, 2011
- Role of a Phase Factor in the Boundary Condition of a One-Dimensional Junction, JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL, 43(35), 20100729
- Dicke-type energy level crossings in cavity-induced atom cooling: Another superradiant cooling, PHYSICAL REVIEW A, 79(4), 2009
- The Dicke-Type Crossings among Eigenvalues of Differential Operators in A Class of Non-Commutative Oscillators, INDIANA UNIVERSITY MATHEMATICS JOURNAL, 58(4), 1493-1535, 2009
- Regularities of ground states of quantum field models, KYUSHU JOURNAL OF MATHEMATICS, 61(2), 321-372, 2007
- Infrared catastrophe for Nelson's model - Non-existence of ground state and soft-boson divergence, PUBLICATIONS OF THE RESEARCH INSTITUTE FOR MATHEMATICAL SCIENCES, 42(4), 897-922, 2006
- Binding Energy for Hydrogen-Like Atoms in the Nelson Model without Cutoffs, Journal of Functional Analysis, 220(2), 424-459, 200503
- Ground State for Point Particles Interacting Through a Massless Scalar Bose Field, Advances in Mathematics, 191(2), 339-392, 200503
- A Model of Interband Radiative Transition, Journal of the Mathematical Society of Japan, 56(3), 753-786, 2004
- Recent Developments in Mathematical Methods for Models in Non-Relativistic Quantum Electrodynamics, A Garden of Quanta: Essays in Honor of Hiroshi Ezawa, 209-242, 2003
- Ground State Transition for Two-Level System Coupled with Bose Field, Physics Letters A, 294(1), 13-18, 2002
- Ground State of a Spin-1/2 Charged Particle in a Two-Dimensional Magnetic Field, Journal of Mathematical Physics, 42(8), 3334-3343, 2001
- Stability of Ground States in Sectors and Its Application to the Wigner-Weisskopf Model, Reviews in Mathematical Physics, 13(4), 513-527, 2001
- Remarks on the Ground State Energy of the Spin-Boson Model. An Application of the Wigner-Weisskopf Model, Reviews in Mathematical Physics, 13(2), 221-251, 2001
- Ground States of a General Class of Quantum Field Hamiltonians, Reviews in Mathematical Physics, 12(8), 1085-1135, 2000
- Canonical Quantization on a Doubly Connected Space and the Aharonov-Bohm Phase, Journal of Functional Analysis, 174(2), 322-363, 2000
- On an expression of the ground state energy of the spin-boson Hamiltonian, Mathematical Methods of Quantum Physics: 2nd Jagna International Workshop: Essays in Honor of Professor Hiroshi Ezawa, 99-107, 1999
- Anomalous Pauli Electron States for Magnetic Fields with Tails, Letters in Mathematical Physics, 50(2), 103-114, 1999
- On the Absence of Eigenvectors of Hamiltonians in a Class of Massless Quantum Field Models Without Infrared Cutoff, Journal of Functional Analysis, 168(2), 470-497, 1999
- An Inverse Problem in Quantum Field Theory and Canonical Correlation Functions ----- An Application of a Solvable Model Called the Rotating Wave Approximation, Journal of the Mathematical Society of Japan, 51(2), 337-369, 1999
- An Expression of the Ground State Energy of the Spin-Boson Model, Journal of Functional Analysis, 162(1), 178-218, 1999
- On the Existence and Uniqueness of Ground States of a Generalized Spin-Boson Model, Journal of Functional Analysis, 151(2), 455-503, 1997
- General Properties between Canonical Correlation and the Independent-Oscillator Model on a Partial *-Algebra, Journal of Mathematical Physics, 37, 121-146, 1996
- A Mathematical Relation between the Potential of the Rotating Wave Approximation and an Estimation of the Fluctuation in Mori's Theory, Annals of Physics (N.Y.), 234(2), 185-210, 1994
- Mori's Memory Kernel Equation in Equilibrium Quantum Systems in Finite Volume, Annals of Physics (N.Y.), 229(2), 354-383, 1994
- Stochastic problem solving by local computation based on self-organization paradigm, Proceedings of the Hawaii International Conference on System Sciences, 3, 82-91, 19940101
- Mori's Memory Kernel Equation for a Quantum Harmonic Oscillator Coupled to RWA-oscillator, Annals of Physics (N.Y.), 224(2), 301-341, 1993
- Rigorous Construction of Liouville Space and Thermo Field Dynamics for Bosonic Systems in Mathematics, Annals of Physics (N.Y.), 223(1), 1-36, 1993
- Quantum Simulation of Interaction between Atom and Light, RIMS Kokyuroku, 2089, 177-177
- Quantum Simulation of Interaction between Atom and Light, RIMS Kokyuroku, 2089, 177-185, 201808

### Invited Lecture, Oral Presentation, Poster Presentation

- Topological Superconductors in Ferromagnetic Nanowires with Domain Wall, Ichimura, Masahiko; Hirokawa, Masao, Ichimura, Masahiko; Hirokawa, Masao, 2019 Joint MMM-Intermag Conference, 2019/01, Without Invitation, AIP Publishing, LLC and the IEEE Magnetics Society, Washington, DC
- Topological Superconductors in Ferromagnetic Nanowire with Domain Wall, Ichimura, Masahiko; Hirokawa, Masao, Ichimura, Masahiko; Hirokawa, Masao, The 79th JSAP Autumn Meeting, 2018, 2018/09, Without Invitation, The Japan Society of Applied Physics, Nagoya Congress Center
- Approximated Eigenstates of Generalized Quantum Rabi Model with A^2-Term in Deep-Strong Coupling Regime, Hirokawa, M, Strongly Coupled Light-Matter Interactions: Models and Applications, 2018/07/09, With Invitation, Lanzhou University, Lanzhou, China
- Quantum simulation of atom coupled to Bose field(s), Hirokawa, Masao, Phenomena Mathematics Seminar, 2017/12/12, With Invitation, Kyushu University IMI, Fukuoka
- Quantum simulation of the atom-light interaction, Hirokawa, Masao, Quantum Circle, 2017/09, Without Invitation, Doppler Institute, Prageu, Czech
- Virtual and real photons in ground state of generalized quantum Rabi model in ultra-strong coupling regime, Hirokawa, Masao, Moller, Jacob; Sasaki, Itaru, Mini-Workshop on ``Virtual Photons in Ultra-Strongly Coupled Systems'', 2017/01/26, With Invitation, RIKEN, Wako, Japan
- A Mathematical Analysis of Dressed Photon in Ground State of Generalized Quantum Rabi Model Using Pair Theory, Hirokawa, Masao, Moller, Jacob; Sasaki, Itaru, Physical and mathematical approaches to interacting particle Systems -In honor of 70th birthday of Herbert Spohn-, 2017/01/12, With Invitation, T. Funaki(Tokyo), T. Miyao(Hokkaido), K. Takeuchi(Tokyo Tech.), T. Sasamoto(Tokyo Tech.), Tokyo, Japan
- A Mathematical Analysis of Photon in Ground State of Generalized Quantum Rabi Model with the A^2-Term, Hirokawa, Masao, Moller, Jacob; Sasaki, Itaru, International Workshop on Ultra-Strong Light-Matter Interactions: Theory and Applications to Quantum Information, 2016/09/19, With Invitation, Quantum Technologies for Information Science, University of the Basque Country, Bilbao, Spain
- On the Hepp-Lieb-Preparata quantum phase transition for the quantum Rabi model, Hirokawa, Masao, Moller, S. Jacob; Sasaki, Itaru, Tuesday Seminar of Analysis, 2016/06/21, With Invitation, Graduate School of Mathematical Sciences, the University of Tokyo, Tokyo, In my talk, I would like to consider the quantum Rabi model from the point of the view of quantum phase transition. Preparata claims that the ground state of the matter coupled with light is dressed with some photons provided that the coupling strength grows large though those photons should primarily be emitted from the matter in the relaxation of quantum states, and then, that the perturbative ground state switches with a non-perturbative one (Hepp-Lieb-Preparata quantum phase transition). He finds this based on the mathematical structure of the Hepp-Lieb quantum phase transition. Yoshihara and others recently showed an experimental result for the quantum Rabi model in circuit QED. In the experiment, they succeeded in demonstrating the so-called deep-strong coupling regime and the ground state dressed with a photon. We consider the quantum Rabi model in the light of the Hepp-Lieb-Preparata quantum phase transition. Our research is among the studies with aspects of mathematical physics, and deals with the A2-term problem.
- A Mathematical Analysis of Photon in Ground State of Generalized Quantum Rabi Model Using Pair Theory, Hirokawa, Masao, Moller, S. Jacob; Sasaki, Itaru, RIKEN Seminar, 2016/07/25, With Invitation, Prof. Franco Nori, Wako, Saitama, Japan
- A Mathematical Alien's Adventure in the Physically Actual World, Hirokawa, Masao, Special Seminar about Frontiers of Materials Science, 2016/06/10, With Invitation
- Introduction of a mathematical approach to sum-frequency generation in non-linear optics, Hirokawa, Masao, Mathematical quantum field theory and related topics, 2016/06/08, With Invitation, Institute of Mathematics for Industry, Kyushu University, Fukuoka
- How is the ground state of the quantum Rabi model dressed with a real photon?, Hirokawa, Masao, Sasaki, Itaru; Moller S. Jacob, Mathematical quantum field theory and related topics, 2016/06/08, Without Invitation, Institute of Mathematics for Industry, Kyushu University, Fukuoka
- On the Hepp-Lieb-Preparata quantum phase transition for the quantum Rabi model, Hirokawa, Masao, Sasaki, Itaru; Moller, S. Jacob, Technical Committee on Quantum Information Technology, 2016/05/31, With Invitation, The Institute of Electronics, Information and Communication Engineers, Japan, Kouchi
- Quantum Phase Transition, Hirokawa, Masao, Joint Mathematics and Physics Seminar, 2016/03/17, With Invitation, Aarhus University, Aarhus
- Mathematical Modeling for Quantum Devices, Hirokawa, Masao, Joint Mathematics and Physics Seminar, 2016/03/17, With Invitation, Aarhus University, Aarhus, Denmark
- A Mathematical Aspect of A Tunnelling Phase for Spintronic Qubit, Hirokawa, Masao, Asia-Pacific Workshop on Quantum Information Sciences 2014, 2014/12/12, With Invitation, National Cheng Kung University, Tainan, Taiwan
- Two Mathematical Aspects of The Interaction between A Two-Level Atom and A One-Mode Light, Hirokawa, Masao, Mathematics and Physics of Interacting Quantum Systems, 2014/10/23, With Invitation, Institute of Mathematics for Industry, Kyushu University, Fukuoka

## Social Activities

### History as Committee Members

- Member of the Commission 18 of The International Union of Pure and Applied Physics, 2014/11, 2017/10, The International Union of Pure and Applied Physics
- Member of The Board of The International Association of Mathematical Physics News Bulletin, 2009/10, 2015/09, The International Association of Mathematical Physics
- A Member of the International Advisory Committiee, 2016/09/19, 2016/09/21, QUTIS Bilbao

### Organizing Academic Conferences, etc.

- 2017/09, 2017/09
- The Interdisciplinary Workshop on Quantum Device 2017, Organizing Committee, 2017/03, 2017/03
- The Interdisciplinary Workshop on Quantum Device 2015, organizer, 2015/10, 2015/10
- Satellite Seminar of IWQD2015---Camp for Young Researchers---, organizer, 2015/10, 2015/10
- Quantum Information Workshop, organizer, 2015/02, 2015/02
- Frontiers in Quantum Metrology, 2014/09, 2014/09
- The Interdisciplinary Workshop on Quantum Device 2014, organizer, 2014/03, 2014/03
- The Interdisciplinary Workshop on Quantum Device 2013, Organizing Committee, 2013/01, 2013/01
- BIT's 7th Annual World Congress of Nano Science & Technology 2017, Forum 4: Nano-Electronics and Microsystems, Session 405: Quantum Dot, Quantum Wire, Quantum Well., Co-Chair, 2017/10, 2017/10
- International Conference on Challenges in Quantum Information Science, Chair of Organizing Committees, 2018/04, 2018/04