vol. 105 | iTHES

Vol. 105, December 7th, 2015


  • Announcement
  • Event report
  • Person of the week

Person of the week

Yuki Yokokura



From the Office

The office of iTHES assistant, Ms.Chikako Oota is situated at the second floor of the main research building, room # 246. The extension number is 3261. She will be at the office from 10 a.m. to 16 p.m.


"On Centennial of General Relativity" --T. Tada

As the end of the year 2015 approaches, let me ponder the significance of the year. I do not mean to reflect what happened this year, though. The scientific research is NOT at all about events, competitions, or breaking records. The true significance of a particular achievement can be appreciated only upon its passing the test of time. Therefore, it does not suit for immediate media events like press releases or conferences, in a very fundamental way.
So, on what could we say having qualified that test General Relativity, without a doubt.
Hundred years ago, Albert Einstein spent November of 1915, sending short communication letters every Thursday to the Prussian Academy of Sciences in Berlin. With these (rather numerous) communications and other documents Einstein left, we have a pretty good idea about the passage that lead Einstein to the so called Einstein equation (see the picture and the link to it) on his fourth letter to the academy dated on November 25th, 1915, which was published on December 2nd, 1915.
It is idiosyncratic that Einstein almost all by himself arrived at the expression that is exactly the same form we know. Most of the formulations of laws of physics were gradually developed over a long time, many scholars contributing. For example, there is no inventor of quantum physics. It is the product by many researchers, including Einstein himself. Another example would be the Maxwell equation since we owe the expression as we know of, actually to Heaviside. In this regard, Einstein’s achievement stands out.
Now it is a hundred years after the conception of the General Relativity; we are yet to understand the very fundamental aspect of it, which is the quantum nature of GR or gravity. It is, of course, one of the most intensely studied subjects in contemporary theoretical physics. We seem to have a lot more to explore.

“Parallel Computing for Visualization using Google Cloud Platform”

Tomohide Wada (iTHES Associate/ABBL) and Tomoya Takiwaki (iTHES Associate/ABBL) succeeded to make a movie of a numerical simulation of a core-collapse supernova together with JSOL Co. Ltd., using Google Cloud Platform. Using the platform (i.e. cluster machines), they succeeded to make the movie in 4.8 hours, which would take 17 days if they used a single CPU computer. The parallel computing for the visualization have made it possible to make a more impressive, high-resolution movie in a short time. This work was announced as a press release at the HP of JSOL and RIKEN on 30th Nov. There, you can see the movie too:
This collaboration was initiated by our communication with Google Tokyo Branch. Google introduced JSOL to us, and now JSOL has become one of our partners for Academic-Industrial Collaborations. JSOL is now going to be open to other researchers who are interested in the parallel visualization using the Google Platform. You can find contact information to JSOL in the press release.

Event report

The 13th iTHES colloquium was taken place on November 10th, inviting Prof. Kazuyuki Aihara from the University of Tokyo as a speaker.
Prof. Aihara began with the dress, designed by Eri Matsui and conceptualized by him for the fashion show, “Tokyo collection” in March 2010. The dress was based on a 2D chaotic map. Throughout his talk, he introduced various examples of mathematical engineering studies by his research group, including theory of neural activities, monkey experiments, demonstration of memory about multiple precise images on a neural network, and theory of gene-protein dynamics.
He also discussed the combination between dynamical systems theory and control systems theory. Dynamical systems theory and control systems theory are usually characterised by nonlinear dynamics without inputs and linear dynamics with control inputs, respectively. For example, the combination enables us to analyze bifurcation diagram even for a model with uncertainty such as noise that can be applicable to gene-protein network with chemical noise.
During and after his talk, there were many questions from audiences, including “How did you make the dress with mathematics?” and “What is “control”?”. Various and beautiful examples of his researches fascinated many audiences.

The international symposium on Yochiro Nambu’s physics was held in Osaka University on November 16th, in which not only Prof. Nambu’s great work in physics was reviewed, but also his influence on the latest research was introduced. In the symposium, Prof. Makoto Kobayashi recalled how Nambu’s renown work on the symmetry breaking affected the discovery of the third generation of quarks in the standard model. Furthermore, Prof. Burt Ovrut discussed about the supersymmetry breaking and the hunting of new particles beyond the standard model. In addition to particle physics, Prof. Toshimitsu Yamazaki explained the connection between chiral symmetry restoration and the nucleon-nucleon interaction in the high-density nuclear system. Moreover, Prof. Nambu’s research also indirectly affected some of current developments in string theory. In the symposium, Prof. Tohru Eguchi introduced interesting Moonshine phenomena in string theory and Prof. Hirosi Ooguri discussed the subtle properties of quantum entanglement between the conformal field theory and string theory. Besides physics, in retrospect of Nambu’s career and from the messages of his former colleagues and friends, one realizes that Prof. Nambu is not only a great physicist but also a great human being. His legacy will continue playing an important role in the new frontier of physics in the next generation.

Person of the week

Yuki Yokokura is a new ithes researcher in the ithes-mcc team. He is interested in quantum gravity and string theory, gravity and black hole, and thermodynamics and non-equilibrium physics. He is now working on black hole evaporation and information problem, and constructing a new view of thermodynamic entropy.