It's certainly true that light has momentum, but after a superficial glance at those papers I agree that they are too weird to worry about. Their basic ingredients are just the ones that people have been working on for about 100 years, so I strongly doubt that such basic points have somehow been missed. We'll look for a competent person to have a closer look.
OK, let's get back to the part I can answer, about light's momentum. This momentum has been known, quantitatively, since Maxwell. Think of an electromagnetic plane wave ExB
hitting a thin sheet of weakly conducting material. (We keep it thin so the fields are almost the same on the way out as in.) Let's work in CGS units, to keep things simple.
The current density in the sheet is J=E
σ, where σ is the electrical conductivity. The power dissipation density is then E·J
σ. That's the rate at which the wave is dumping energy into the sheet, per unit volume. The rate at which it's dumping momentum into the sheet is just, by definition, the force. The force per unit volume in the direction of the wave (the only part that doesn't average to zero over an oscillation) comes from the magnetic force on the current, whose magnitude (per unit volume) is BJ/c= E2
σ/c. (In CGS, the magnitudes E and B are equal for a wave in free space.) The reason this doesn't change sign as the fields oscillate is that it involves the product ExB
, not just one of the oscillating fields.
So the momentum loss rate is just the energy loss rate/c. This can be applied over many layers until there's nothing left of the wave, so we have that the momentum magnitude p of the wave was just its energy/c.
I'm not sure exactly when Maxwell figured this out, but it may have been in the 1860's.
Whoa- I read more of that paper. Completely nuts.
(published on 02/25/12)