Obituary of Akira Tonomura (1942-2012)

Akira Tonomura was born in Hyogo, Japan in 1942 and graduated from the University of Tokyo with a degree in physics. Upon graduation he joined the Hitachi Central Research Laboratory, where he later attained the title “Fellow” in 1999.

In the 1970s, Tonomura did pioneering work in the development of the electron hologprahy microscope and observed lines of magnetic force for the first time in the world. Building on this, in 1986, he experimentally verified the Aharonov-Bohm effect, which had eluded definitive experimental proof for a long time. This experiment proved that vector potentials, which are nothing more than a mathematical concept in classical physics, are in fact physical quantities that are more fundamental than electric or magnetic fields.

Tonomura was also known for his observations of magnetic vortex movement in superconductors.