Re: chaos and uncertainty

Lee March (
Sun, 18 Jul 1999 01:33:04 -0500

Spike Jones wrote:

> Yup, photons do behave strangely. In college I was
> shown the famous double slit experiment, wherein a
> laser forms a horizontal spread, as you called it. You
> can send photons through double slits, and form
> a pattern of high and low illumination on the wall behind.
> This is explained by wave interference. But now you
> can turn the power to the laser so low, that the photons
> pass through *one at a time*. If you do that, you can
> observe that the pattern does not go away. Therefore, each
> photon must be somehow splitting into a wave, waving
> through *both* slits, interfering with *itself*, creating
> the interference pattern on the back wall. QM is weird
> stuff, James. spike


Maybe you can help me here. I was trying to remember the other QM demo from college physics in which the beam is passed through a slit or pair of slits that are vertical, thus screening out all the side to side waves or particles, then through a slit or pair of slits turned 90 degrees .......and then it all gets foggy in my mind. If I remember right it ends up that the particles still have the same intensity as if they had never passed through the first slits, etc.

Anyone who can jog my memory on this, or the name of the demo would be much appreciated.