I understand you’re getting ready to choose a laboratory.

Yes, I’m wavering between going into theory, or jumping into experimentation. Going into theory involves using mathematical expressions to represent or predict natural phenomena, whereas experimentation involves measuring and experimenting to reveal natural phenomena. I’ve always liked the former, and thought that I would like to become a theorist, but recently I have become interested in experimentation too.

Why is that?

I am interested in observation of cosmic rays, and that is part of the reason for my interest in experimentation. However, you have to have agreement between observation of natural phenomena and mathematical expressions or it isn’t physics! That is, no matter how much you theorize about something, if the results of experimental observation of physical phenomena don’t agree with theory, there’s a problem with the theory. So the observation of phenomena is essential.

What are cosmic rays?

Cosmic rays are sub-atomic particles that fly through space at high energies. These include the well-known neutrinos that were observed during the KamiokaNDE experiment designed by Masatoshi Koshiba, winner of the 2002 Nobel Prize in Physics. And just last year, Takaaki Kajita, head of the Institute for Cosmic Ray Research at the University of Tokyo, was also honored with the 2015 Nobel Prize in Physics for his cosmic ray research.

In cooperation with JAXA, one of the laboratories at Waseda University has installed “CALET,” an instrument for cosmic ray observation, aboard the International Space Station. Observational data collected by the instrument has been sent to earth, and will soon undergo analysis. One of the things that makes Waseda so attractive is its involvement with such advanced research.

What sort of theoretical studies are you doing?

The academic level at the Department of Physics is very high, and it took two years of study just to learn the basics. Then I got together with four or five friends from the department and we are holding our own “seminars” to learn together from the latest physics publications. We divide ourselves up by area, and the person responsible for an area will give a presentation using a white board, and then together we discuss points that are unclear and read between the lines of mathematical expressions. One book I remember as particularly difficult was “Gendai no Ryoshi Rikigaku” (Modern  Quantum Mechanics), by J.J. Sakurai.  The one we are working on now is “Ba no Ryoshi-ron” (Quantum Field Theory) by Makoto Sakamoto.

What is involved in the study of quantum mechanics and quantum theory?

Quantum mechanics is a theory which explains the properties of electrons and other sub-atomic particles. The behavior of such particles does not conform to what is expected of matter at the level of daily observation, and therefore it can be hard to understand. Analogies do not help in this regard because they cannot provide sufficient accuracy. This means that quantum behavior must be understood in terms of abstract concepts.

Could you give some advice to people seeking admission?

Yes, I’d like to emphasize that a good grasp of fundamentals is vital. When you really like a subject, the tendency is to want to dive straight into applications and development, but I think it is also important to keep in mind studying aimed at deepening understanding of basic knowledge. For example, there’s no use in simply memorizing a theorem; you really have to understand how the theorem was derived and whether there are alternate means of arriving at the same conclusion. If you go at your studies that way, you’ll gain a firm foundation for any application.