What Is Light/Photons?

[iPeppers]

For the longest time I thought light (or photons) were both particles and waves. Recently a professor at school told me that it was actually more that photons were not particles nor waves, but instead something new. This new thing does not have any other real life example that we can say it acts as, but has certain properties of both particles and waves, but not all of them.

 

What kind of properties do photons share with particles, and what properties do they share with waves? What new properties do they have that are unlike anything else?

 

Where is the newest research on light going?

 

(I realize these are heavy questions and may have very long answers, but if you enjoy typing those answers, I enjoy reading them! I have also been to wikipedia and other basic sources, so more links aren't necessarily helpful, but the way in which people on here would try to explain this stuff, is. I'm just curious.)

[Severian]

When talking about wave particle duality, you might find this post I made a while a ago useful.

 

I will try and go into more detail later when I have more time, but for now let me say that light is a consequence of the phase symmetry in Quantum Mechanics. In QM, physical things only depend on the square of the wavefunction, so if you multiply the wavefunction by a complex phase nothing changes. This is a symmetry and light is a consequence of requiring that symmetry to be local, that is, I can make the phase shift differently depending on where I am.

[iPeppers]

I read your other post, severian, and it was quite interesting. But if every particle is actually just a bunch of waves, then do they all tend to exhibit the same qualities of waves that light does? Why is light always singled out for our first introduction into wave-particle duality?

[Mr Skeptic]

I call them all wavicles. They all actually act as a particle or a wave under different conditions. When things get big enough their wavelength is tiny so it doesn't matter though. See the de Broglie equations. http://en.wikipedia.org/wiki/Matter_wave#The_de_Broglie_relations