Question about double slit experiment with detectors

In summary, the double slit experiment (DSE) has been performed with detectors on both the ingoing and outgoing sides of the slits, as well as more complex setups. The purpose of the detector is to detect the photons, which requires an exchange of energy and ultimately destroys the photon. This explains why the interference pattern disappears when a detector is used. However, the important observation is that the photons are detected at one slit or the other, not in a continuous or half-and-half manner. The calculation of the interference pattern takes into account both slits, similar to how the outcome of dice tossing is predicted by considering all possible numbers. A recommended resource for a deeper understanding of the experiment is a lecture by Scott Aaronson.
  • #1
o-man
2
0
I've read that when one performs the double slit experiment (dse) without any detectors to "see" which slit the photon goes through one gets an interference pattern. When one places a detector to see which slit the photon goes through the interference pattern disappears. My question are these.

1. Has the DSE been done with a detector on the ingoing side of the slits and then the outgoing side of the slits?

2. What exactly do the detectors do? As near as i can figure for the detector to detect it has to interact with the photon and the only way it can do that is by exchange of energy. If that is true then the photon in the experiment with the detector and the photon in the experiment without the detector likely don't have the same energy to begin with or/and end with. Or am i missing something entirely?

As always thanks for reading.
 
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  • #2
1. yes - and much more convoluted approaches too.
2. depends on the detector and what it is supposed to detect.
For photon - yes: a photon detector has to destroy the photon it detects.

In the case of doing the experiment with photons, then, it is not surprising to find the interference pattern destroyed. The important observation, then, is that the photons are detected at one slit or the other - they are never half-and-half or continuous as expected from a classical wave.

We could use a detector which only detects a photon half (or some other fraction) of the time ... what do you think happens then?

It's misleading anyway - each photon passes randomly through one or the other slit but the way we calculate the interference patters includes terms related to both slits. Not for each individual photon but for the pattern as a whole.

It's a bit like how the pattern in dice tossing can be predicted only by taking account of all the possible numbers that could be rolled even though each individual toss only shows one number.

The following lecture is fast becoming a fave:
http://www.scottaaronson.com/democritus/lec9.html
... it's very abstract, but shows up how the math works.
 

1. What is the double slit experiment with detectors?

The double slit experiment with detectors is a classic experiment in quantum physics that demonstrates the wave-particle duality of light. It involves shining a beam of light through two parallel slits onto a screen, and observing the interference pattern that is created. In this version of the experiment, detectors are placed at the slits to determine which slit the particles pass through.

2. What is the purpose of using detectors in the double slit experiment?

The detectors in the double slit experiment are used to determine which slit the particles pass through. This allows us to gather information about the path of the particles, which is crucial in understanding the wave-particle duality of light. Without detectors, the particles would behave purely as waves and not create an interference pattern.

3. How do the detectors affect the outcome of the double slit experiment?

The detectors in the double slit experiment affect the outcome by collapsing the wave function of the particles. This means that the particles are no longer in a state of superposition and behave only as particles, resulting in a pattern of two distinct bands on the screen rather than an interference pattern.

4. Can the double slit experiment be performed without using detectors?

Yes, the double slit experiment can be performed without detectors. In fact, the original version of the experiment did not use detectors and instead observed the interference pattern created by the particles. This version of the experiment highlights the wave-like nature of particles.

5. What does the double slit experiment with detectors tell us about the nature of light?

The double slit experiment with detectors tells us that light has both wave-like and particle-like properties. When the detectors are used, the particles behave like particles and when they are not used, they behave like waves. This phenomenon is known as wave-particle duality and is a fundamental concept in quantum mechanics.

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