Introduction You might have seen figure skaters spinning around quickly and then tucking their arms to spin faster—or opening them to spin more slowly. This happens, thanks to a physics concept known ...

Surprising as it may sound, 107 years after the introduction of general relativity, the meanings of basic concepts are still being worked out. More than a century after Albert Einstein unveiled ...

This course introduces the quantum mechanical concept of angular momentum operator and its relationship with rotation operator. It then presents the angular momentum operators, their eigenvalues and ...

When we look out into the universe, we find objects tend to orient themselves in nice, flat planes. For those who don’t know the physical processes behind this phenomena, this seems extremely strange ...

In the beam of light emitted by a laser pointer, photons travel predominantly along one direction and the beam is therefore said to be collimated. The electric field carried by these photons is ...