I think you're confusing quantum mechanics with packets of light, a.k.a. photon quanta.
Quantum mechanics does deal, in part, with light as the photon (force carrier particles) released by electrons (negatively charged portion of an atom
with almost no mass compared to its counterparts, protons and neutrons).
I believe the equation is:
mass * gravity = weight, where '*' = multiplication
For those who don't know what "mass" is... or were given the, "It is the amount of 'stuff' inside of an atom,"-speech, like I was... "mass"
is the total material/matter an atom contains that is effected by gravity.
Force carrier particles have no known mass. So the above equation would yield:
0 * gravity = 0, for the weight (or almost zero).
In fact, any gravitational value, alone, would be cancelled by force carriers having zero mass.
Note: Edited to correct content.
Side note: A photon is considered to be a Boson, but a massless Boson (aka force carrier). Other Bosons are theorized to have mass, but not
necessarily in the Standard Model (the old way looking at atomic structure). So, it is possible that Bosons have a minute amount of mass, but still
relatively zero. Also, as stated above, photons are considered massless.
[edit on 29-4-2005 by Protector]