Shun Arai's

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"Look deep into nature, and then you will understand everything better. "


I'm a Ph.D candidate of Nagoya University and University of Edinburgh Joint Degree Program. My expertise is going to be cosmology and gravitation (in detail, see Research).

My research is aimed to reveal the nature of gravity for better understanding of the world. Among the four fundamental physical interactions we have currently known, gravity is outstandingly universal. Not only binding our feet on the earth, or sculpture the shape of deep trough of the sea and peaky mountains, but also in the outer space, gravity bonds planets and stars systematically, webs a millions of galaxies, and makes the whole universe expanding at the largest distance observed over the last ten billon (13.7 billions) years.

Surprisingly, these extraordinary features of gravity has been explained by a simple geometrical mathematics of General Relativity. In other words, gravity could be understandable only with a small number of principles. However, the current understanding of gravity is likely to be modified beyond this simplicity in many aspects. The gravity seems to be the weakest force at the atomic scale but why? In terms of a quantum theory, General Relativity have been controversial with conceptual problems (e.g, EPR paradox). Moreover, a usual matters inevitably leads a geometrical singularity in a gravitationally collapsed object, i.e, singularity theorem.

Especially, in the cosmological context, it is believed that the universe expands acceleratingly at least twice; inflation and late-time acceleration. Moreover, there is not enough amount of matters the to bond the structures gravitationally at galaxy scales. Interestingly these two phenomena have a good match with observational data. These could ask us what is gravity once again.

For these reasons, it is ideally better that both theoretical and observational researches get synergized than ever before. It is important to research the nature of gravity as much various ways as we already have. I would like to contribute for understanding the world better through the research of gravity.