Why does Mat's medallion hurt the gholam?

Question

In the Wheel of Time series, at one point we see Mat get in a fight with a gholam, and he hits the gholam with his Foxhead (One Power Canceling) medallion. When he hits the gholam, it is burned.

Do we know why this happens?

Answer 1

Jordan RAFOed this in an interview:

Dragoman: How does Mat's medallion damage the gholam? Also, what significance to the Seanchan does his spear have?

Robert Jordan: [Laughing...] Read and Find out. If I tell you, you get bored with the new books!

I'm not aware of anywhere this has been covered in later books, so it could be that we'll never know. (Perhaps the RAFO just referred to the second of the two questions above.)

---

However, I found a very interesting possible explanation on this page, which develops a faux-science theory of gholam, ter'angreal, and the One Power. Here it is (emphasis mine):

The medallion dissipates flows channeled at the bearer and at the medallion itself, and it grows cold when dissipating flows of the Power. This could be an inherent flaw or to allow the bearer to detect channeling. I believe that it is a reaction to the dissipation of the One Power flows. The medallion acts as a grounded capacitor of the One Power. It takes flows and puts them into a buffer to dissipate into the surroundings.

Both gholam and ter'angreal dissipate flows of the Power: the ter'angreal dissipating into its surroundings, the gholam into itself. The extreme similarity of the two acts much like two ter'angreal reacting to each other. When two similar ter'angreal are in the same room, a resonance can be felt. The resonance creates a field of energy between the two objects. This energy is evident between the gholam and the ter'angreal, in that when the two come into contact the molecules of the weaker one is broken down. (In technical terms, the activation energy of the carbon chains and rings that are the make up of the molecular structure of carbon based flesh is lowered and the energy of the subatomic particles is raised. In doing so, it allows for the separation of bonds, usually H20 and C2. The most often occurrences of this form of separation are usually burning or freezing.)

This accounts for when the medallion comes in contact with the gholam; the gholam is burned. The medallion is trying to force a dissipation of the Power built up within the gholam. The resonance and the dissipation work in conjunction to break down the cellular structure of the gholam. The main point of this is to show the weak points of each. The medallion draws the flows into a buffer and by doing so gets cold. As all capacitors work there is a limit to how much can be drawn into the buffer. Once that point is reached anything further can harm the capacitor, in this case ter'angreal, to the point of destruction. The gholam acts as a well, pulling the One Power into its self or its buffer until its buffer is full. Any further addition to the well will weaken its structure and its ability to dissipate, and will make it more susceptible to the possibility of it being destroyed using the One Power it draws in.