Interpretation of Negative-Energy States Diracs Hole Theory

we introduced two important quantities (i) the Bohr magneton = eh/lmeC and (ii) the gyromagnetic ratio of the electron g = 2, which is also known as the Landi factor. This value derived from Dirac theory reproduces the experimental result for the gyromagnetic ratio very well. 

The operator quadratic in the vector potential, /2meC, is often called the diamagnetic term and the remaining magnetic-potential operators linear in B (or A, respectively) are called paramagnetic terms. 

It is important to note that everything that has been said in this section transfers directly to the many-electron Dirac equation in chapter 9 and all subsequent chapters. 

Interpretation of Negative-Energy States Dirac s Hole Theory 

Of course, Dirac was well aware of the many difficulties arising from the electron-positron interpretation — from the mass-dissymmetry if the negative-energy electron was a proton to the fact that he has actually created a many-particle theory which, as a true many-particle theory, would have been difficult to study. We shall have a closer look into these difficulties below. 

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