When the wavelength is long, this can be used without any problems.

This is the one thing, magnetism is truly jealous of.

From a classical perspective, this gauge is the most direct way to describe light-matter interaction.

This can make calculations shorter and even potentials disappear.

This is the amount of energy by which a particle is lifted, on average, by an oscillating light field.

You must change l by one and may change m_l at most by one.

Despite being usually deemed unphyiscal, it can be used to describe circularly polarised light fields or light fields in the rotating frame.

In a light field, this property of a particle might not be what it seems.

In the Bloch sphere, this process brings you straight from the north pole to the south pole and back again as many times as you want.

It pulls and pushes, but sometimes it also twists and turns its victims.

When the spotlight is turned on, but no-one else is around, this is the state a particle will gladly stay in.

In this frame, the Hamiltonian successfully transferred (almost) all his job to the wave function.

Despite its name it is neither black nor white - in fact one might say it is almost the opposite.

Even without anything quantum, this will still blow up a charged particle's energy if one is not careful.

In all honesty, this is just a fancy name for a transformation into the interaction picture.