[coolgod]

The three polarizing filter experiment using common sources of light can be explained perfectly without using quantum mechanics [0]. These effects only need QM to explain in the single photon regime. The polarized light from the LED display is definitely not in the single photon regime thus this experiment does not demonstrate any quantum effects. Without any quantum effects, it is much more difficult to justify the quantumness of this supposed quantum computer.

[0] http://alienryderflex.com/polarizer/

[ahelwer]

I was going to say, this wouldn't explain it because the electric field strength is projected to the polarization axis (with strength 0.707 at 45 degrees) but to match quantum measurement it should be 0.5 strength (0.707 squared). But as the grandparent comment stresses, light intensity is the square of electric field strength... so the measurement matches. Makes sense! I will amend my above comment.