Kei Yosida

Theory of the Antiferromagnetic Resonance Absorption in CuCl22H2O

T. Nagamiya has developed a theory of antiferromagnetic resonance absorption in the case that the applied static field strength is weaker tban the geometrical mean of the exchange field and the anisotropy field. In tbis paper his theory is extended so as to apply also to the case that the former field is stronger than the latter geometrical mean, and is compared with the experimental results obtained for CuCl22H20 by Gorter et al.

Collective Excitations in Superconductors

The collective excitations in superconductors are invest gated on the basis of the Bogoliubov method. The result obtained by Anderson is confirmed that the plasma frequency In superconductors is completely the same as that in the normal state. It is also shown that the C.S. Meissner effect is really gauge invariant. (auth)