Instability in magnetic materials with dynamical axion field ~ A research method in particle physics contributes to condensed matter physics ~ (Physical Review Letters Editor's Suggestion)

A joint research by researchers from two different science fields, elementary particle physics and condensed matter physics, predicted a new phenomenon in magnetic materials with dynamical axion field. Though the feasibility to detect axion by an elementary particle experiment is yet unknown, it is predicted that the new instability may be observed in a condensed matter experiment by adjusting the material. This result will be published in Physical Review Letters as an Editors' Suggestion. It is the first publication by a joint research between the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) and the Institute for Solid State Physics (ISSP).

The Kavli IPMU and the ISSP are located next to each other in the University of Tokyo Kashiwa campus. The research fields in each institute seem to be completely different at first glance, however, a joint research by researchers from both institutes focusing on the similarity between undiscovered elementary particle axion and topological insulator resulted a prediction of a new type of phase transition under a strong electric field.

The axion is a hypothetical elementary particle postulated to resolve the strong CP problem in the quantum chromodynamics. To detect axion, there have been many experimental trial with various detection idea such as applying strong magnetic field, convert axion to the photon in a crystal of germanium, or injecting high intensity laser in a strong magnetic field. However, any of the experiments have not yet detected positive results.

“Elementary particle axion has been considered that it must exist for many years but yet undetected”, Hitoshi Murayama, Director at Kavli IPMU says, “It seems to take still long time to find axion by particle physics experiment. On the other hand, quite similar excitation to axion appears in the topological insulator and their interaction may be able to be observed. It is very interesting prediction and should boost the research on the elementary particle axion. Additionally, it is very good example that researchers in different research fields, particle physics and condensed matter physics, may collaborate and inspire each other using common mathematical language ‘quantum field theory’.”

Before starting this joint research, Hirosi Ooguri, Professor at California Institute of Technology and Principal Investigator at Kavli IPMU, studied a new idea of detection method for elementary particle axion applying strong electric field instead of magnetic field. However, required electric field is too strong hence it is impossible to apply this method with current experimental technology.

“IPMU and ISSP held a joint international workshop in 2009, the year that the building of IPMU was built next to the ISSP building”, says Yasuhiro Iye, Director of the ISSP. “This is one important outcome from the research exchange between two institutes since the joint workshop.”

It was known that in a topological insulator, magnetic fluctuation plays a role of the dynamical axion field. Masaki Oshikawa, Professor at ISSP and Hirosi Ooguri studied the axionic electrodynamics in the presence of a background electric field. It has been pointed out that the axion field exhibits instability. The instability then leads a complete screening of an applied electric field.

In contrast to the elementary particle axion whose parameters should be determined by the nature, physical parameters of axion field in the condensed matter experiments can be selected by adjusting doping materials. Especially, when one reduce the effective mass of the axion, the possibility to observe the phase transition will be raised. It is pointed out that the new phenomena will appear also in the usual (non-topological) insulator depending on the combination of magnetic and electric fields.

Yasuhiro Iye also said, “Though the particle physics and the condensed matter physics are quite different in their scale of the length and energy scale, there are many similar points in their mathematical formulation and theoretical concepts. This research is a suggestion that topological insulator might be available to verify a new idea for the yet undetected particle axion appeared in the research on AdS/CFT correspondence which is recently growing remarkably in the elementary particle physics. I expect to gain more progress by keeping successful exchange between the institutes.”




Physical Review Letters (Editors' Suggestion)
April 11, 2012 Online


Instability in magnetic materials with dynamical axion field


Hiroshi Oguri, Professor at California Institute of Technology and Principal Investigator at Kavli IPMU, University of Tokyo,
Masaki Oshikawa, Professor at ISSP, the University of Tokyo



Scientific Contacts  

Hiroshi Ooguri   E-mail: h.ooguri _at_  
Masaki Oshikawa   E-mail: oshikawa _at_ Phone: +81-4-7136-3296

Media Contact:  

Public officers, Kavli IPMU Yoshihisa OBAYASHI / Tomomi HIJIKATA
E-mail: press _at_ Phone: +81-4-7136-5974/5977 Fax: +81-4-7136-4941

General affairs office, ISSP Yuki HASHIMOTO   
E-mail: issp-somu _at_ Tel: 04-7136-3207

(Please replace _at_ by @)


The Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)

The Institute for the Physics and Mathematics of the Universe (IPMU) was launched in October 2007 as one of the World Premier International Research Center Initiative (WPI) of the Ministry of Education, Culture, Sports, Science and Technology with the University of Tokyo as the host institution in order to address deep mysteries of the universe by integrating the forefront knowledge of physics and mathematics. The Name of the Institute was changed to the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) in April 2012 after the University of Tokyo decided to receive an endowment from Kavli Foundation.

The Institute for Solid State Physics (ISSP)

The Institute for Solid State Physics (ISSP) of the University of Tokyo was established on April 1 in 1957 as a joint research laboratory based upon the recommendation of the Science Council of Japan and the concurrence between the Ministry of Education, Science and Culture and the Science and Technology Agency in order to carry on basic research in condensed matter physics. ISSP was relocated to the new campus in Kashiwa of the University of Tokyo in March 2000 after the 43 years of activities at the Roppongi campus in downtown Tokyo. Here ISSP is aiming at creating new areas of science in collaboration with other institutions in Kashiwa.

Editors' Suggestion in Physical Review Letters

See the announcement