Interpretations of quantum eraser experiment

In summary, the interference pattern can be restored by using a magnefying glass, but it is still unclear as to what is actually causing the interference.
  • #1
dave137
2
0
Hi

My interpretation of how observing the double slit experiment removes the interference pattern was that when (for example) an electron interacts with a photon, the electron is forced to be "at" that position, collapsing it's wavefunction. Then as the electron continues on towards the screen the probability of it going through the other slit is small or negligible from this location (in or next to one of the slits) and so no interference takes place. (this could be way off)

Having seen this though

http://www.scientificamerican.com/media/inline/DD39218F-E7F2-99DF-39D45DA3DD2602A1_p95.gif

I don't know what to think. If by using the magnefying glass the interference pattern can be restored then it's not so much the interaction with the photon, but the existence of certain information that destroys the interference pattern. Does the interaction even collapse the wavefunction as i doubt the collapsed wavefunction could be un-collapsed?

Is there a generally excepted interpretation of what is going on here? I assume that if the magnefying glass is placed far enough away so that the electron hits the screen before the photon reaches the magnefying glass then there is no interference pattern?

Thanks in advance for any comments

ps. I wouldn't have said that after a simple interaction like this the electron and photon would be entangled, but surely they must be here?
 
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  • #2
dave137 said:
Does the interaction even collapse the wavefunction as i doubt the collapsed wavefunction could be un-collapsed?

Is there a generally excepted interpretation of what is going on here?

There are lots of proposed solutions to the measurement problem, none are accepted outside their small circle of proponents. You'll have to solve MP before you can solve quantum eraser.
 
  • #3
dave137 said:
http://www.scientificamerican.com/media/inline/DD39218F-E7F2-99DF-39D45DA3DD2602A1_p95.gif

I don't know what to think. If by using the magnefying glass the interference pattern can be restored then it's not so much the interaction with the photon, but the existence of certain information that destroys the interference pattern. Does the interaction even collapse the wavefunction as i doubt the collapsed wavefunction could be un-collapsed?

Is there a generally excepted interpretation of what is going on here? I assume that if the magnefying glass is placed far enough away so that the electron hits the screen before the photon reaches the magnefying glass then there is no interference pattern?

As RUTA states, the "true" picture is a matter of interpretation.

Collapsed wave functions can be recombined (thus restoring an earlier state)! An example would be sending an entangled photon "Alice" through a polarizing beam splitter, and then carefully recombining the 2 output paths so that knowledge of polarization is lost. The recombined Alice beam will still be polarization entangled with Bob.

Because the interpretations are mostly equivalent mathematical devices, most claim that such result is consistent with their interpretational assumptions.
 
  • #4
One thing I can't figger out is this: With the quantum eraser, the interference pattern is lost when we shine light on the particles that create the interference pattern.
If this is so, then why do diffraction gratings still act like superprisms?
 
  • #5
Okay. I can't do the maths for the double slit experiment, but i know it qualitatively, either by working out the probabilities of each path or using Feynman's sum over paths method and i can imagine some picture of what's going on, how interference occurs. (i've not studied dynamic systems like this, only harmonic oscillators or potential wells)

Is there a mathematical solution to this experiment? So that i can try and interpret that, I'm happy to learn new maths but if it's the whole of QED or anything then obviously i don't expect anyone to explain it all to me.

Thanks
 

FAQ: Interpretations of quantum eraser experiment

1. What is the quantum eraser experiment?

The quantum eraser experiment is a thought experiment designed to demonstrate the counterintuitive nature of quantum mechanics. It involves the use of a double-slit experiment and a device known as a quantum eraser to show that the behavior of particles can change depending on whether or not we observe them.

2. How does the quantum eraser experiment work?

In the experiment, a beam of particles, such as photons, is directed towards a barrier with two slits. On the other side of the barrier, there is a screen that records where the particles land. When the particles are not observed, they behave like waves and create an interference pattern on the screen. However, when a detector is placed to determine which slit the particles pass through, the interference pattern disappears. The quantum eraser then allows the particles to behave like waves again, even though they were observed.

3. What are the different interpretations of the quantum eraser experiment?

There are several interpretations of the quantum eraser experiment, including the Copenhagen interpretation, the many-worlds interpretation, and the pilot-wave theory. These interpretations attempt to explain the paradoxical results of the experiment and the behavior of particles at the quantum level.

4. What is the significance of the quantum eraser experiment?

The quantum eraser experiment challenges our understanding of reality and the role of observation in quantum mechanics. It also has practical applications in quantum cryptography and quantum computing, where the manipulation of particles' behavior is crucial for secure communication and computing.

5. How does the quantum eraser experiment relate to the famous Schrödinger's cat thought experiment?

Both the quantum eraser experiment and Schrödinger's cat thought experiment highlight the strange and paradoxical nature of quantum mechanics. They both involve the concept of superposition, where particles or objects can exist in multiple states at once until they are observed or measured. The quantum eraser experiment shows that the mere act of observation can determine the behavior of particles, while Schrödinger's cat thought experiment illustrates the concept of quantum entanglement, where two particles can be connected even over long distances.

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