Bending of Light in diffraction? Is it actually possible?

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1. Feb 20, 2016

I know light has wave particle duality, I understand these two points very well,
1. Light moves as a probability function, taking all the possible paths at once. The alternate paths cancel themselves out, resulting in a particle-like combined motion.

2. When relatively close to an edge, some paths will collide in the edge and their opposing pairs are thus not annihilated and continue at bent trajectories around the edge.

What I really want to know is, are those bent trajectories actually possible?
The gravitational pull of the earth is not enough for the photons to take up a bent trajectory like a rock thrown. So, how can we explain this bent trajectory?

2. Feb 20, 2016

A. Neumaier

3. Feb 20, 2016

I don't understand how we can explain that with the help of geometrical optics, I am asking for a bit elaborate answer. As light can not actually bend but, in diffraction phenomenon, light seems to be apparently bending.
I gave the article a read, could not find what I was looking for(That is, the diffraction phenomenon in quantum physics). It would be very helpful if you could quote that here.

4. Feb 20, 2016

A. Neumaier

I had quoted the piece that is relevant. Light has a wave nature, which bend, and light rays are perpendicular to all light fronts. In a diffraction experiment, this leads to bent rays at the fringes.

Last edited: Feb 20, 2016
5. Feb 20, 2016

Staff: Mentor

Here is the quantum answer to diffraction:
http://arxiv.org/ftp/quant-ph/papers/0703/0703126.pdf

As you can see no 'bending' involved. The apparent 'bending' is simply the uncertainty principle at work. At the slit you know its position so its momentum is unknown and after the slit can go off in all sorts of crazy directions.

Thanks
Bill

6. Feb 20, 2016