Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

according to Spin of an electron Dirac said the electron has Two possible spins if i'm correct.

Do Electrons have polarity? measurable by its Dirac spin or probabilistically by its quantum states?

share|improve this question
2  
What do you mean by "polarity"? –  twistor59 Jun 12 '13 at 17:05
    
measurable magnetic poles certainly. like in altering a electron spin by its magnetic poles instead of by its quantum states. i'm talking about Dirac electrons. –  sphericsf Jun 12 '13 at 17:14
    
Electron is not a magnetic monopole. It has zero "magnetic" charge. –  Trimok Jun 12 '13 at 17:48
    
@Diego Its not very clear what you are asking, so its difficult to answer your question. But yes if you are asking if electrons behave like tiny magnets then answer is yes. –  Prathyush Jun 12 '13 at 18:04
add comment

1 Answer

An electron has a magnetic moment and it is proportional, as a vector, to the spin itself: $$ \boldsymbol{\mu}_S=- g_S \mu_B \frac{\mathbf{S}}{\hbar}. $$ Here, $\hbar$ is the reduced Planck's constant, $\mu_B$ is the Bohr magneton, a helpful combination $e\hbar / 2 m_e$, and $g_S$ is the spin $g$-factor $$ g_S\sim 2.00231930419922 \pm (1.5 × 10^{-12})$$ Because the magnetic moment is "essentially" the spin, the $x,y,z$ components of the magnetic moment refuse to commute with each other. But you may choose an axis, e.g. the $z$-axis, and the magnetic moment may be "up" or "down", just like the spin. It means that the electron is a "bar magnet" oriented in the North-South or South-North way in the case that the spin is up or down, respectively.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.