# Tagged Questions

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### Why is the movement of electrons random in electric field?

Suppose an uncharged conductor is present isolated and there is no net electric field applied. Then by assumption we have the motion of electrons random,i.e. isotropic. But now suppose there is a ...
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### Intuition/derivation behind the probability current definition

The definition is: $${\bf{j}} = \frac{\hbar}{2mi} (\psi^* \nabla \psi - \psi \nabla \psi^*)$$ However: Where ever I have looked, the above "pops out of nowhere". I was wondering how can I obtain ...
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### Electric current in quantum mechanics?

Quick question: I want to find an expression for the (electric) current density of an electron, in quantum mechanics. Either a single electron or a general charge distribution $\rho$. Classically ...
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### current density in 1-d

I have a slight problem with the notion of the current density in one dimension. For example the probability current in 1-d given by: $J(x) = -\frac{1}{m} Im(-i\psi^*\partial_x \psi)$ calculation the ...
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### Probability current vs. direction of wave function

I did an exercise for my Quantum-Mechanics Lecture: Let $\hbar$=2m=1. A particle in 1 dimension has $j(x)=2\ Im(\overline{\psi} (x) \ \psi'(x))$ and it's to show that there are superpositions \$\psi ...