How can you detect which path an electron will take in a double-slit experiment?

[maka89]

Say, you're running an electron double-slit experiment, firing one electron at a time, only that half of the screen where you record the interference pattern is moved further away from the slits. How would that affect the interference pattern?
Would the electrons still go in the same ratio 50/50 to the left / right half of the screen?

How if you're fiing a electron beam insted of one at a time?

 

[DrChinese]

It would not materially affect the results.

 

[drvrm]

Would the electrons still go in the same ratio 50/50 to the left / right half of the screen?

does an interference phenomena depends on the 'observer' -his presence or absence?

 

[DrChinese]

does an interference phenomena depends on the 'observer' -his presence or absence?

As far as anyone knows, the answer is no.

The standard issue about the presence or absence of interference is whether it is possible (in principle) to know which slit the particle passes through. If the answer is yes to that question, then there is no interference. And vice versa.

 

[drvrm]

How if you're fiing a electron beam insted of one at a time?

the number of electrons being sent to double slit experiment does not affect the interference phenomena ,however a low intensity will require larger time for recording the pattern. such experiments have been conducted and results are on the net.

 

[maka89]

So if you fire a single electron, and the detector on the left screen doesn't detect anything, you can know ahead of time that the electron will hit the right side of the screen? Does is this not which path information? Not implying any of that consciousness bologny, just getting my mind blown by this stuff and want to understand it xD

 

[newjerseyrunner]

The double slit experiment gets way way weirder. Look up the quantum eraser experiment. Making the slits lead down different paths does not matter.

 

[DrChinese]

So if you fire a single electron, and the detector on the left screen doesn't detect anything, you can know ahead of time that the electron will hit the right side of the screen? Does is this not which path information?

How would you learn anything ahead of time? At any rate, there are a number of different techniques to learn the which-slit information. If you do, there is no interference.