Question: I know that when AC is passed through the primary coil of a step-up transformer a higher emf is induced in the secondary coil (with more turns) of the transformer. Since energy is conserved, and P = VI, this would mean a drop in current. But I'm not able to visualize what is really happening to the electrons in the secondary coil. Does a higher voltage in the secondary coil mean that all electrons in the secondary coil are taken to a higher potential? And why is the current (flow of electrons) low when that happens?

What is really happening to the charges in the secondary coil?

Answer: 
Consider this. You have two particles and you want to know what the probability is to find particle 1 at $r\_1$ and at the same time particle 2 at $r\_2$. Both particles live in the same 3D space but each particle has its own set of three coordinates. The 6 dimensional square modulus wavefunction is the function that answers this question. You provide two sets of coordinates and you obtain the probability density to find particle 1 at $r\_1$ under the condition that particle 2 is at $r\_2$, which is why a multiparticle wavefunction magnitude squared is a joined probability density function.

I'd also like to make the destinction between probability and probability density. The density is
$$
|\psi(r\_1,r\_2)|^2
$$

The probability is
$$
P=\int^{r\_1+\Delta r\_1}\_{r\_1}\int^{r\_2+\Delta r\_2}\_{r\_2}| \psi(r'\_1, r'\_2)|^2dr'\_1dr'\_2 \approx |\psi(r\_1, r\_2)|^2\Delta r\_1\Delta r\_2
$$
which gives us the probability to find particle 1 in a small volume around $r\_1$ and particle 2 in a small volume around $r\_2$. By making $\Delta r$ small we can say for practical purposes that the particles are at $r\_1$ and $r\_2$.
The six-dimensional space is the [configuration space](https://en.wikipedia.org/wiki/Configuration_space_(physics)) of the particles. If the particles have positions $\mathbf x$ and $\mathbf y$ in physical space, this configuration is represented by a single point $(\mathbf x , \mathbf y)$ in configuration space. The square of the amplitude of the wave function $|\Psi (\mathbf x , \mathbf y)|^2$ at a point $(\mathbf x , \mathbf y)$ in this configuration space is, roughly speaking, the probability that the particles will have positions $\mathbf x$ and $\mathbf y$ respectively in physical (more precisely, $|\Psi|^2$ is a [probability density function](https://en.wikipedia.org/wiki/Probability_density_function)).