iTHEMS Weekly News Letter

Seminar Report

Dr. Shunji Matsuura thumbnail

Dr. Shunji Matsuura from 1QBit gave a series of lectures


Our visitor Dr. Shunji Matsuura from 1QBit, a startup company specializes in quantum computing and quantum information technology based in Vancouver, Canada gave a series of lectures from May 13 (Mon) through May 15 (Wed). Dr. Matsuura started with a basic explanation of qubits and their entanglement. Then, he moved on to explain various method employed in the field of quantum computing, such as Variational Quantum Eigensolver (VQE). His explanation was especially clear to physicists, since Dr. Matsuura’s background is string theory receiving his Ph.D. in string theory from the Perimeter Institute for Theoretical Physics and the University of Tokyo, and he used to conduct research at the Kavli Institute for Theoretical Physics (University of California, Santa Barbara), McGill University, Riken, YITP (Kyoto University), and the Niels Bohr Institute (University of Copenhagen). His current research focuses on the fundamental aspects of quantum-enhanced optimization, such as error correction and speedup, which are also of interest to some iTHEMS members, and we are hoping a lot of fruitful collaborations between iTHEMS and Dr. Matsuura as well as 1QBit group in future.

Hot Topic

The First Coffee Meeting Talk in Reiwa Era (Dr.Nagisa Hiroshima)


The first 15 min. coffee meeting talk in Reiwa era was given by Nagisa Hiroshima on May 10. She explained how to extract the density distribution of dark matter from observation.

Research News

Masaru Hongo was highlighted in a recent article of RIKEN RESEARCH
Dr. Masaru Hongo thumbnail

Masaru Hongo was highlighted in a recent article of RIKEN RESEARCH "Describing the early Universe by simplifying complicated equations"


A powerful mathematical method for simplifying the analysis of highly complex systems has been extended by a RIKEN-led team. This will enhance its usefulness for researchers in a wide range of fields.

Upcoming Events

Special Lecture

How did the Universe Begin? -Inflation Theory & Road to the Proof-

May 21 at 15:00 - 16:30, 2019

Dr. Katsuhiko Sato (Professor Emeritus, The University of Tokyo / Director, Research Center for Science Systems, Japan Society for the Promotion of Science)

Venue: Okochi Hall, 1F Laser Science Laboratory, RIKEN

Broadcast: R511, Computational Science Research Building, R-CCS, Kobe Campus, RIKEN / SUURI-COOL (Kyoto), #204-205, 2F Maskawa Building for Education and Research, North Campus, Kyoto University / SUURI-COOL (Sendai), #303, 3F AIMR Main Building, Advanced Institute for Materials Research (AIMR), Tohoku University

Event Official Language: Japanese


AIMR Main Building venue photo

g-RIPS Sendai 2019

June 17 - August 9, 2019

GRIPS (Graduate-level Research in Industrial Projects for Students)-Sendai program was held last summer (June 18 - Aug. 10, 2018) with the support of iTHEMS as well as other institutions and companies. Two industrial projects were launched under the suggestion of TOYOTA and NEC, and two teams composed of US and Japanese students have worked intensively to find solutions of these problems. See for the details of the GRIPS program and the summary of activities at GRIPS-Sendai 2018.

This year, GRIPS-Sendai program will be held from June 17 through Aug. 9, 2019 with a larger scale under the support of iTHEMS. Stay tuned for further information.

Venue: 4F Research Space, AIMR Main Building, Advanced Institute for Materials Research (AIMR), Tohoku University

Event Official Language: English


Workshop on Sine-square deformation and related topics 2019 thumbnail

Workshop on Sine-square deformation and related topics 2019

July 11 at 10:00 - 18:00, 2019

Sine-Square Deformation (SSD) is a newly found boundary condition that involves the spatial modulation of the coupling constant of quantum systems.
Since its discovery, it has received broad attention in the context of various research field. This workshop aims at offering the opportunities for the researchers interested in SSD to convene and exchange ideas on the subject.

Venue: #435-437, Main Research Building, RIKEN

Event Official Language: Japanese

Featured Paper of the Week

Comments on holographic entanglements in cutoff AdS thumbnail
Dr. Toshihiro Ota thumbnail

Comments on holographic entanglements in cutoff AdS


AdS/CFT correspondence tells us that a gravity in AdS space is equivalent to CFT which lives on the boundary of the AdS. Recently it has been proposed that an integrable TT deformation of CFTs produces a deformed AdS/CFT. According to the conjecture, the AdS boundary is located at a finite radial cutoff. To investigate the deformed correspondence, we studied holographic entanglement entropy in the cutoff AdS, which is well known as a probe of information theoretic quantity. In particular, we explored its phase transitions. For two-interval entanglement entropy, the transition point monotonically decreases with a deformation parameter, which means that by the TT deformation the degrees of freedom in subsystems are decreasing. Our result implies that the effect of the TT deformation can be regarded as the rescaling of the energy scale.

Toshihiro Ota
"Comments on holographic entanglements in cutoff AdS"
arXiv: 1904.06930

Person of the Week

Dr. Kanato Goto thumbnail

Self-introduction: Kanato Goto


My name is Kanato Goto and I have been working at iTHEMS since April 2019. I am a theoretical physicist studying string theory and my main research interests lie in foundational questions about quantum gravity, black hole physics, and supersymmetric quantum field theories. I am currently trying to understand the basic mechanism and the mysteries of the holographic principle, which states that information about gravity and the spacetime contained in our three-dimensional universe can be completely described by the two-dimensional boundary surrounding it, just like a hologram emerges from a sheet of photographic film. At iTHEMS, I hope to broaden my research horizon through discussions with researchers in various fields.

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