## Happy Holidays and a New Year

In Japan, we take a week off around the New Year's day. This is a custom probably goes back to the old days when the New Year bestowed a much greater significance upon Japanese people. For example, people count their ages based on the New Year's day. Come the New Year, you and everybody else get one year older! So, in a sense, everybody celebrates not only the new year but also everybody's birthday.

This issue of iTHES Newsletter is the last one for the year 2013. We will be back on January 6th, 2014. We wish you all very Happy Holidays and a New Year!

## Upcoming Event

## Person of the Week

Koji Hashimoto

Inter-disciplinary activity --- your approach?

Extreme theoretical sciences include mathematics -- although mathematics does not necessarily describe nature of our world, it is inevitably coupled to science of our world, since any science uses mathematical language. Superstring theory, which is a candidate theory for describing all forces and matter in the universe, has served as a kind of pure mathematics in its long history. No one found experimentally that the elementary particles in this world are tiny string, that is why the superstring theory is not totally based on natural science.
I am Koji Hashimoto, an extreme theoretical physicist, in the sense that I am working on superstring theory. You may be surprised to know that until 2006 all of my published papers include no physical units. That is the world of superstring theory. However, after 2007 when I joined RIKEN, we superstring theorists found a way to apply our mathematical formulas to nature, and now the superstring techniques can be found everywhere in physics: not only in elementary particle physics, also in hadron physics, nuclear physics, and even in condensed matter physics and astrophysics. So are my papers.

This interdisciplinary expansion of the ideas in superstring theory is, I think, based on the fact that we superstring theorists had no prejudice on scales --- since we have lived in the mathematical world with no unit for long years. As you can easily imagine, normally equations are associated with concrete dynamical images in your brain, and so your experience on equations actually prevents you from jumping into an application of your equations to other phenomena in nature whose scale is completely different from the original scale. For instance, it would be difficult for you to imagine that quantum gravity calculates high-Tc superconductors, and black holes calculate quark deconfinement. But this is in fact true, and my research is in fact about these.
Freeing your mind helps you a lot for interdisciplinary science, for sure! Why don't you try some? By the way, you can go even beyond the disciplines in science. Interdisciplinary activity between inside and outside of science is filled with excitement, please check out my youtube video: http://www.youtube.com/watch?v=_hMaCCDnZ7o