| Home / lib / P_Physics / | ||
Mehra J. Physicist's conception of nature (Dirac Festschrift, D.Reidel, 1973)(KA)(T)(860s)_P_.djvu |
|
Size 8.5Mb Date Jun 22, 2005 |
instance, spins 0 and 1 can be jointly described in terms of an algebra of 16x 16
matrices which, however, is reducible into representations corresponding to the spins
0 and 1 separately, without affecting the properties of these particles (Dufi&n, 1938;
Kemmer, 1939; see also Part II, 4, of Pauli, 1941)...
In this formalism, the probability amplitudes y/ of the electrons and <p of the
neutrinos, and their complex conjugates y/* and (p*, are considered as non-commutative operators
acting on functions of the occupation numbers of the quantum states of the electrons and neutrinos......
Singular (~r~^) terms in the
static tensor force could be cancelled out by introducing a vector field beside the
pseudoscalar one (Moller and Rosenfeld, 1940; Schwinger, 1942; the struggle to make
this type of theory agree with the deuteron data is reviewed in Section 3 of Wentzel,
1947)...
In this regard, we were all led astray by
the mistaken identity of the cosmic ray mesons! Ironically, the apparent weakness
of their nuclear interaction was one of the major motivations for work on the strong
coupling theory, as well as for other contemporaneous speculations...
Heitler
A941) developed a quantum theory of radiation damping which he applied to meson-
nucleon scattering...
Now, as an example, let
us consider a system composed of A'^ particles, and let the coordinates of each particle
be Fj, r2,..., Fjy...
That is to say, the probability amplitude is given as a function of the field
strength at different space points and of one common time variable...
Many people tried various means to overcome this problem of
infinite quantities, but nobody succeeded...
* The main purpose of the work of the work of Bloch and Nordsieck, and Pauli and Fierz was to
solve the so-called infrared catastrophe which wis one of a number of divergences...
Sakata pointed out the
possibility that the electromagnetic mass and the negative new mass cancel each other
and that the infinity could be eliminated by suitably choosing the coupling constant
between this field and the electron...
Owing to this new,
more lucid method, we noticed that, among the various terms appearing in both
Dancoff's and our previous calculation, one term had been overlooked...
It is a very pleasant thing that no divergence is involved in the theory except for the
two infinities of the electronic mass and charge...
The Lamb shift is a phenomenon in which the energy levels of a hydrogen atom show
some shifts from the levels given by the Dirac theory...
This
topic is intended to be an example of the general theme of the symposium - the
'Development of the Physicist's Conception of Nature'...
One
electron added to this infinite sea would be stable against spontaneous photon
emission, as befitted a physical particle...
The inhomogeneous term originates in the discontinuity of G(x,x') at x° = x°',
thereby introducing 5(x° — x°'), which discontinuity is measured by the equal-
time anticommutator of the fields, a unit matrix multiple of d{x—x')...
Very small distances or, equivalently, very high momenta make
a disproportionately large contribution to the results, with the consequence that
solutions to the coupled equations do not really exist - at least, not in the sense of a
perturbative expansion...
The
formal (!) solution of this and the analogous Maxwell system is given in terms of
functional delta functions by
Then the functional Fourier construction
d[n]5[J] = jldil,-][.dA]e''''^y'"'^-'^^
supplies the explicit integral expression (to within a constant factor),
<0+ I 0_>'''' = r [diA] [d^] e'^^l''''''*-"'^*'
-W14,.A1)
It continues to surprise me that so many people seem to accept this formal statement
as a satisfactory starting point of a theory...
| © 2007 eKnigu | ||