Our colleague Hiroyasu Miyazaki moves on to a new carrier at NTT Communication Science Laboratories as of March 1st. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Hiroyasu Miyazaki:

My academic life is full of precious memories with iTHES and iTHEMS members. When I first joined the group, I was a bit worried since there were only a few mathematicians in RIKEN. But that was unnecessary. Everybody was very kind to me and every communication was really enjoyable. And the pleasure kept becoming larger and larger. I will certainly miss you and the heart-warming atmosphere in iTHEMS, but the life never stops.

I am moving to a private research institute called NTT-IFM (Institute for Fundamental Mathematics) on March 1st. I am supposed to work as a mathematician. So there will still be a lot of opportunities for discussion with you. If you will find me wandering in Wako campus (or anywhere else), please catch me and talk to me! Of course you are very welcome to visit NTT-IFM if you are interested. Let’s keep in touch and see you again soon!

Dr. Enrico Rinaldi (iTHEMS Visiting Scientist) has been featured in institutional website.
"Dude, what if everything around us was just … a hologram? The thing is, it could be—and a University of Michigan physicist is using quantum computing and machine learning to better understand the idea, called holographic duality."

See related links for details.

Dr. Genki Hosono gave us a stimulating talk on pluripotential and $L^2$ methods in complex geometry. The talk was carefully designed not only for non-mathematicians but also for experts around the topic. He began his talk with the definition and basic properties of subharmonic function and its multivariable version in complex geometry: plurisubharmonic function. He then introduced Bergman kernel and explained a variational approach to Ohsawa-Takegoshi $L^2$ extension theorem, which is an extension theorem of holomorphic function with a bound on $L^2$ norm weighted by a plurisubharmonic function. Finally he explained Deng-Wang-Zhang-Zhou’s result on a `reverse direction’ of Ohsawa-Takegoshi theorem and his result with Inayama on a variant result. His explanations were very clear and quite valuable for us.

Reported by Eiji Inoue

Takumi Hayashi (Tokyo/RESCEU) gave a talk on Lorenzian path-integral approach to false vacuum decay [1]. Conventionally, false vacuum decay has been discussed within the Euclidean formalism developed by Coleman, but it may suffer from several subtle issues when applying to cosmological problems. Takumi proposed a new formulation for false vacuum decay and computed the bubble nucleation rate by directly evaluating a Lorenzian path integral based on the Picard-Lefschetz theory. Takumi discussed nucleation of bubbles with various sizes, not limited to the critical one only to which the Euclidean formalism can be applied, and showed that nucleation of small bubbles is more probable than the critical one. More than 20 physicists have joined the seminar and enjoyed fruitful discussions.

Reported by Hidetoshi Taya