Master’s student Liu Yifan from Oshikawa Group conducted research through ISSP International Research Opportunities for Student Program at the Kavli Institute for Theoretical Physics (KITP) in the United States from April 29 to May 24, 2024. This program, initiated in 2017, aims to foster international talent through collaborative research abroad, sending graduate students to overseas research institutions for several months.

LIU, Yifan (Oshikawa Group M2)

Purpose

To explore the properties of state-operator correspondence in 2+1- dimensional conformal field theory, particularly focusing on the possible realization in the torus topology. Additionally, participating in the program would allow me to learn more recent applications of (boundary) conformal field theory in correlated gapless systems.

Summary

Through participating in the program “Correlated Gapless Quantum Matter,” I discussed with many scientists working on the cutting-edge topics of conformal field theory in condensed matter theory. Additionally, I had an opportunity to chat with Prof. Chepiga and continued our collaboration on finding the conformal boundary conditions for the Ashkin-Teller model.

Activity

Correlated gapless quantum matter represents an inclusive class of physical problems and includes both stable phases and quantum critical points. Recently, there has been much exciting progress in exploring the 2+1d quantum critical points through newly developed numerical methods and non-perturbative analytical techniques. Focusing on the possible construction of the state-operator correspondence on torus/cylinder geometry in 2+1d conformal field theory (CFT), I discussed with many leading figures in this area and obtained several insights into the study of defect/boundary 2+1d CFT. Moreover, as a possible extension of my previous research on 1+1d boundary CFT, I discussed with experts in the study of the gapless symmetry protected topological (SPT) phase and gained many novel ideas in applying the results of boundary CFT into the research of gapless SPT.

This program also provided me with a valuable chance to discuss my recent progress face-to-face with Prof. Chepiga, a collaborator from the Delft University of Technology. We actively exchanged our recent ideas and made several plans for future collaboration. After revising with her comments, I finished a manuscript and submitted it (arXiv: 2405.06891).

During my stay, I visited the California Science Center in Los Angeles, near Santa Barbara. Outside the center, the iconic Endeavour, NASA’s space shuttle, stands tall, captivating visitors with its impressive presence. This historic spacecraft serves as a powerful symbol of humanity’s extraordinary journey into space exploration, offering a tangible connection to the wonders of the cosmos.

Reflections and prospects for future research

Exposure to a vibrant environment where I could interact with leading scientists was invaluable for my early research endeavors. It allowed me to explore a wide range of new topics and undertake phenomena in experiments I had never considered before. Additionally, engaging with experimentalists has provided insights into the physics topics that interest various communities, guiding my focus as a young theoretical physicist. This cross-disciplinary exchange will undoubtedly shape my future research, enabling me to delve into the physics of broad interest with a well-rounded perspective.

Related pages

• Oshikawa Group, ISSP, UTokyo
• 2024.6.24 ISSP News International Research Opportunities for Students Program Report of SCOLLON, Myles Forrester