S-Matrix Theory and Entanglement

Kazuo Fujikawa

Published Jun 29, 2015• 0 citations

Abstract

But no good and simple criterion of entanglement for more complicated cases is known. This situation is rather strange since everybody talks about entanglement. How to produce and how to measure the entanglement are also interesting issues. When one measures the spin of the electron, for example, there are three major operators one can think of [1] a) Wigner spin, b) Dirac spin, c) Magnetic moment. The notion of chirality is important to distinguish these operators. Incidentally, many people talk about the Stern-Gerlach apparatus to measure the spin polarization of the electron. This is also strange since N. Bohr and N. F. Mott and other prominent people have shown many years ago that one cannot measure the electron spin polarization by a Stern-Gerlach apparatus, since the inhomogeneous magnetic field disturbs the motion of the electron so much and it is impossible to detect the spin orientation. The Stern-Gerlach particles are electrically neutral. One may ask if novel features appear in high energy physics? Chiral symmetry (including the use of weak interaction) can become important such as in a neutrino-antineutrino pair in Z decay

DOI: 10.7566/jpscp.7.010013

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