Kazuo TANAKA Kazuo TANAKA Kazuo TANAKA

So please jump into the new world you interested in.

People

Kazuo TANAKA

1.What kind of the research are you doing?

I'm interested in the question of how was the world created.

The law of nature is sophisticated and has symmetries. For instance, we learned that distance equals speed times time in an elementary school and it is applicable to any directions. Also, there are so many elegant symmetries in the law.

Let's consider the world that all of positive charge particles change to negative and negative charge particles change to positive. Same as our world, same charges repel each other and opposite charge attract in that world. Thus our world also looks like having the charge symmetry.

On the other hand, the world created by the law has less symmetry, e.g. the universe has the unique distribution of stars, the earth has a rich nature and structure. It is weird because the symmetry law can only create a symmetrical and boring world. That is one of the big questions that how was such a rich world can be created.

This question is closely related to the mystery of antiparticle and so many physicists involved in. Every type of particle has an associated antiparticle that has the same mass but with an opposite electric charge, and we can observe them by pair production of particle and antiparticle from energy by high energy experiment with accelerators. And if a particle colliding with an antiparticle, they can annihilate each other. We believe that a vast number of particles in our world has been created by this reaction from the huge energy at the beginning of the world.

If particle and antiparticle are created and annihilated together, it seems the universe should contain nothing but leftover energy. Nevertheless, only the large number of particles remain and somehow we can't observe antiparticle at all now. Now we consider that some of the symmetries are violated in the law of nature.

In fact, we already discover some symmetry violations such as charge conjunction and parity inversion. Now so many researchers try to find a large symmetry violation to describe this mystery and I am one of the researcher.

In Tohoku University, I search symmetry violations with Francium which is largest alkali atom which sensitive to the symmetry violation. But francium does not exist in the earth so that I produce with the large cyclotron accelerator and trapped by laser. This is the only experimental setup to trap francium atom in Japan and we aim to lead this research field with it.

2.What is the reason for starting your study?

When I was 6 years old, I suddenly came up with the idea that why do I exist in this world. I felt weird that the beginning of the universe is described as if being seen in many books and it seems like a fake story.

I even doubted if people make fiction to hide the truth. I haven't had enough vocabulary to ask it and worried about it for a long time. Sometimes I got scared of the idea that if this world is not stable and suddenly disappeared tomorrow.

After a while, I found that so many physics researcher's motivation is closely related to this problem awareness. I have decided to be involved in physics research because I thought I would feel better even if I can't solve this terribly difficult problem.

3.Message for prospective students

I participated in the first Japan Physics Olympiad when I'm 18 years old and it is one of the big experiences for me. During this competition, I inspired by the fact that there are so many young people of the same generation who like physics. But, I feel that it takes a long time to have such a chance since I start to be interested in this field. I also feel it is unfortunate to take a long time to start physics research since then.

Now I think that opportunities to touch the fundamental physics are not that common compared to the other fields.

From this experience, I start to have a mission to create such opportunities for children in Japan who are interested in this field. For example, I launched the collaboration group to distribute the cosmic-ray detectors to schools and support their research activity since 2018. Also, I organize "Accel Kitchen" which provide the chance to take part in our experiment using francium atom created by cyclotron accelerators for junior high and high school students. In fact, this is the only chance in Japan to use a large accelerator and collaborate with real physicists. Even these two activities are minor, I aim to create the environment for young people can easy to start their research works at any place in Japan.

Now I find that such opportunities are increased recently also in the physics field, e.g. Summer Challenge in KEK, MosiTen in Tohoku Univ. and BL4S in CERN. So please jump into the new world you interested in. And I'd like to provide more unique chance for all young people.

Sometimes I received contact from young people who want to visit and see the cyclotron accelerator at Tohoku University. Of course, I always arrange their visit and support to enhance their motivation. The first step to have a wonderful chance is always just have the courage to contact.

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