Researcher Information

MIYAO Tadahiro

Professor

Unravel the mysteries of the electron by mathematics

Department of Mathematics, Mathematics

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Theme
Study of many-electron systems by means of the operator theory and the theory of operator algebras. 
FieldMathematical physics, Condensed matter physics, Functional analysis
KeywordMany electron systems, Quantum spin systems, Electron-phonon interacting systems, Quantum electrodynamics, Ferromagnetism, Antiferromagnetism, Topological phases, Phase transitions, Renormaliation group, Operator inequalities, Gauss processes, Operator algebras, Schroedinger operator

Representative Achievements

"On the semigroup generated by the renormalized Nelson Hamiltonian", T. Miyao, Journal of Functional Analysis, 276, 1948-1977, (2019)
“Nagaoka’s theorem in the Holstein-Hubbard model”, T. Miyao, Annales Henri Poincar´e, 18, 2849-2871, (2017).
“Retarded van der Waals potential: Revisited”, T. Miyao, H. Spohn, Journal of Mathematical Physics, 50, 072103(2009) (19pages).
“Spectral analysis of the semi-relativistic Pauli-Fierz hamiltonian”, T. Miyao, H. Spohn, Journal of Functional Analysis, 256, 2123-2156, (2009).
“Lowest energy states in nonrelativistic QED: atoms and ions in motion”, M. Loss, T. Miyao, H. Spohn, Journal of Functional Analysis, 34, 689-717, (2007).

Department of Mathematics, Mathematics

MIYAO Tadahiro

Professor

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What is the research theme that you are currently focusing on?

All matter around us is composed of many electrons.
There are various interactions between electrons. For example, electrons may repel each other due to Coulomb forces; or be attracted to each other under the influence of crystal lattice vibrations. Due to these various interactions, a variety of phenomena are known to emerge in a system consisting of many electrons. For example, superconductivity, ferromagnetism, antiferromagnetism, and charge density waves are typical examples that have been known for a long time. My research theme is to mathematically reveal the essence of such a wide variety of phenomena in many-electron systems. In my field of expertise, “mathematical physics,” this subject is known to be very challenging, and various areas of modern mathematics are involved in its exploration. I prefer to employ functional analytic methods such as operator theory, operator algebras, and probability theory in my research on this topic.

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Please tell us your stories until you became a researcher.

Because my graduate supervisor was very tolerant, I could concentrate on my research interests without worrying about what others thought of me. I was fortunate to have obtained my degree in such an ideal environment, but the reality was harsh, and I spent the next five years as a postdoctoral fellow at universities in Japan and Germany. During that period, I was always anxious because I could not foresee the future, but I was constantly encouraged and stimulated by the attitude toward research of the boss of the laboratory I belonged to in Germany, and I was able to solidify the foundation of my current research style. I enjoyed my post-doc period abroad and was happy to be able to devote myself to my research as much as I wanted.

At the summit of Mont Blanc
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What do you usually do when you get stuck in your research?

I am always stuck, so I don’t do anything special and don’t rush. I make a notebook of stuck topics to revisit someday, then quickly forget about them and concentrate on new or concurrent projects. Sometimes the deadlock is broken by accident, and other times it is left unresolved for a long time. There are problems that I was finally able to solve more than ten years after being stuck. I am sure that I was not capable enough at that time to conquer those problems. Preparing for lectures and lab seminars are a nice change of pace.