The first term HO in (5.13) does not contain the electromagnetic potential and has the same
form as (5.6). This part of HVM represents thus the Hamiltonian density of the free meson …

According to the general program proposed in the first paper, Koba, Tati and one of the
present authors have given in the second paper a perfectly relativistic formulation of the …

On a Relativistically Invariant Formulation. 199 which the ψ-vector depends no longer on C,
but the field quantities, on the other hand, depend on C, not only on t. Also in our …

28 S. TOMONAGA where H is the operator representing the total energy of the field which is
given by the space integral of a function of υ and λ. As we adopt here the Sehrodinger …

By means of the formalism of Duffin and Kemmer there is constructed for mesons interacting
with the electromagnetic field a theory that is manifestly Lorentz invariant and also gauge …

It is known that there is a particular kind of projection operator, usually denoted by d (∂), in
terms of which the quantum theory of relativistic free fields can be put in a simple and …

At present, the meson theory is in such an unsatisfactory state that it has not proceeded
much beyond its original hypothetical character and can hardly explain the experiments …

A new analytic continuation principle is described, by means of which the calculation of
matrix elements of Heisenberg operators in any quantized field theory is greatly simplified …

The new field theory has been developed in two papers. The first, quoted as I, contains not
only a classical treatment, but also an attempt at quantization; the second, quoted as II, a …

The main purpose of these lectures is to give an introduction to the theory of invariant linear
wave equations and their associated external field problems. Certain special equations …