What exactly is a single photon in the EM field?

[StationZero]

I'm trying to differentiate the wave-particle duality of light-photons in order to understand what exactly distinguishes a single photon of light. I'm looking for a simplified, I'll even take an oversimplified, definition. I reviewd the wiki pages on photons/polarization, etc. and it's a morass of terms and equations that isn't helping me. I guess, conceptually I'm wondering if a single photon is composed of a single oscillation in the EM field propagating at c. Is it a short series of oscillations? Is it something of a traveling "wave packet" that has a central peak that decays symmetrically, or is something else?

Also, I know a photon has zero resting mass and spin 1, but how could one visualize one traveling through space? A little squiggling sideways S? A wavefront like so, ")"? An ellipse like a photon torpedo from Star Trek? I guess my challenge is to try to describe and define it while eschewing an avisual desciption of it in leiu of equations. Anyone?

 

[phyzguy]

The Journal "Optics and Photonics News" devoted an entire issue to this question, entitled "What is a Photon", and it is available on line at this site.

However, I must say that after reading the articles, I still cannot answer your questions.

 

[Bill_K]

The electromagnetic field can be decomposed into an infinite set of independent modes of oscillation. These are usually taken to be the plane wave solutions, but need not be. Classically each mode behaves like a harmonic oscillator. In quantum mechanics on the other hand, a harmonic oscillator has a ground state and a series of discrete excited states.

A photon is the first excited state of one of the modes.