University of Tokyo
Kavli Institute for the Physics and Mathematics of the Universe
Galileo once remarked that mathematics is the language of the universe, and it is the firm belief at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU). But here, a combination of different approaches based on theoretical physics, experimental physics, and astronomical observations is used for seeking answers to profound problems in cosmology.
The Kavli IPMU, an institute within the University of Tokyo, brings together a wide range of researchers – from pure mathematicians and string theorists to experimental particle physicists and observational astronomers – in a truly multi-disciplinary and collaborative environment. First established in 2007 under a Japanese government initiative as the Institute for the Physics and Mathematics of the Universe (IPMU), the Institute received an endowment from The Kavli Foundation in early 2012 and became the Kavli IPMU.
Housed in a research building at the University of Tokyo’s Kashiwa campus in Chiba Prefecture outside of Tokyo, The Kavli IPMU is led by Hitoshi Murayama, a particle physicist and ambassador for the Institute’s work. Of the Institute’s nearly 200 principal investigators, faculty members, postdoctoral researchers, joint appointments and graduate students, more than half are from outside Japan. Among the Institute’s main research areas:
- Mathematics. The Kavli IPMU regards pure mathematics research as fundamental to its quest to understand the universe. The Institute’s mathematicians, for example, are working on new geometric tools to help string theorists develop a new physical description of the universe that includes six extra dimensions – in addition to the four dimensions of space and time that are familiar to us. Other work in advanced algebra aims to develop laws that govern that description. On the other hand, mathematicians use tools developed in string theory to attack their own problems.
- String Theory. The pursuit of a unified theory that explains both general relativity, which describes the physics of gravity, and quantum mechanics, which describes the physics of elementary particles, may lie in string theory, which postulates that matter at its most fundamental is comprised of vibrating strings. The close relationship between string theory and mathematics has inspired advances in both fields, and collaborations at the Kavli IPMU are ongoing.
- Neutrino Physics. Neutrinos are one of the fundamental particles in the universe and they must have played a role in the development of galaxies in the early universe, but little is understood about them. Experimental evidence to date suggests that neutrinos have mass, but it has never been measured accurately. Two experiments involving researchers at the Kavli IPMU, called SuperKamiokande and KamLAND, both in a deep underground mine, are attempting to detect and characterize neutrinos, while astronomical observations will constrain the neutrino mass as well.
- Dark Matter. The Kavli IPMU researchers are involved in an experiment called XMASS to detect the dark matter particles. Dark matter makes up nearly a quarter of the universe but it is completely unknown. Astrophysicists know of dark matter’s presence by its gravitational effects on galaxies and clusters of galaxies. But direct detection, if it is possible, will require close collaborations with particle physicists working on XMASS and other detection experiments.
- Observational Cosmology. A large view of the cosmos is needed to understand the nature and origin of its largest structures. Using the Subaru Telescope atop Mauna Kea in Hawaii, the Kavli IPMU astronomers are involved in gravitational lensing studies – the phenomenon by which the gravity of foreground galaxies and galaxy clusters distort more distant objects behind them. These and other studies, including a new project to install a wide-field camera on Subaru to conduct a wide-field survey of distant galaxies, will help astronomers better understand the nature of dark energy, which is causing the universe to expand at an accelerating rate.
The Kavli IPMU hosts international workshops and meetings on these and other topics of interest, and over the years it has strengthened relationships with other prominent research programs at U.C. Berkeley, Princeton University and other institutions. Helping to fulfill its founding mission, the Institute has also fostered increased awareness of cosmology through public talks and other activities, in Japan and abroad.
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