Abstract

Quantum spin liquids are exotic quantum states in insulating magnets, where conventional magnetic ordering is suppressed down to the lowest temperature by quantum fluctuations. Among the salient features is the fractionalization of spins into emergent quasi-particles. Since the proposal of an exactly soluble model by Alexei Kitaev in 2006, there has been immense progress in understanding of quantum spin liquids both theoretically and experimentally. In this talk, I will briefly review this rapidly growing topic, with a focus on the spin fractionalization. In magnets well described by the Kitaev model, the spins are fractionalized into Majorana fermions, which are expected as important constituents for quantum computing. We will discuss the recent theoretical and experimental results for the identification of the Majorana fermions.

About Tea Time Talk

AIMR’s Tea Time Talk is a kind of seminar aiming to promote exchange between world’s eminent researchers and young researchers at AIMR, held in a relaxed atmosphere at AIMR’s Friday Tea Time. The following researchers from around the world have given talks at this event so far, and participants have enjoyed discussion over a cup of tea.

•  1st  May 25, 2012  Prof. Thomas P. Russell (The University of Massachusetts Amherst, U.S.A.)
•  2nd  July  6, 2012  Prof. Winfried Teizer (Texas A&M University, U.S.A.)
•  3rd  Aug. 10, 2012  Prof. Alan Lindsay Greer (University of Cambridge, U.K.)
•  4th  Aug. 17,2012  Prof. Alain Reza Yavari (Grenoble Institute of Technology, France)
•  5th  Aug. 31, 2012  Prof. John H. Perepezko (University of Wisconsin-Madison, U.S.A.)
•  6th  Jan. 18, 2013  Prof. Tomasz Dietl (Polish Academy of Sciences, Poland)
•  7th  Apr. 12, 2013  Prof. Yiming Li (National Chiao Tung University, Taiwan)
•  8th  June 28, 2013  Dr. Bjorn Mysen (Carnegie Institution, Carnegie Institution for Science, U.S.A.)
•  9th  Oct.  1, 2013  Dr. Yuan T. Lee (Nobel laureate in Chemistry, Academia Sinica of Taiwan)
• 10th  Nov. 19, 2013  Dr. Pawel Hawrylak (National Research Council Canada, Canada)
• 11th  June 27, 2014  Prof. Michael B. Santos (The University of Oklahoma, U.S.A.)
• 12th  June 26, 2015  Dr. B. Muralidharan (Indian Institute of Technology Bombay, India)
• 13th  May 13, 2016  Prof. Jean-Yves Cavaillé (ELyT MaX (Joint Lab at Tohoku University), University of Lyon, France)
• 14th  June 17, 2016  Prof. Tomoteru Fukumura (AIMR, Tohoku University)
• 15th  Sept. 30, 2016  Prof.  C. Suryanarayana (University of Central Florida, U.S.A.)
• 16th  Nov. 29, 2016  Dr. David Guy Austing (National Research Council Canada, Canada)
• 17th  April 28, 2017  Prof. Ayumi Hirano (AIMR, Tohoku University)
• 18th June 23, 2017 Prof. Denis Arčon (Jožef Stefan Institute, Slovenia)
• 19th June 30, 2017 Dr. Takeshi Nakanishi (AIST-Tohoku U Mathematics for Advanced Materials Open Innovation Laboratory (MathAM-OIL))
• 20th July  7, 2017 Prof. Arun Bansil (Northeastern University)
• 21st July 21, 2017 Prof. Gael Sebald (INSA Lyon, France / ELyT MaX at Tohoku University)
• 22nd July 28, 2017 Prof. Nicolas Mary (INSA Lyon, France / ELyT MaX Lab at Tohoku University)
• 23rd Dec. 8, 2017 Prof. Jean-Yves Cavaillé (INSA Lyon, France / ELyT MaX Lab at Tohoku University)
• 24th April 27, 2018 Prof. Masaru Tsukada (AIMR, Tohoku University)
• 25th May 11, 2018 Dr. Pierre-Antoine Geslin (Mateis lab, INSA Lyon/CNRS / ELyTMaX Lab at Tohoku University / Institute for Materials Research, Tohoku University)
• 26th July 13, 2018 Dr. Shimpei Ono (Central Research Institute of Electric Power Industry, Japan)