So, we start with a standard double slit experiment interference pattern.
Then we add a QWP to determine which way information.
But here is where my first problem arises. Aren't we just ignoring data to produce this pattern? The interference pattern is still happening we're just blocking it at the QWP. Look at the number of hits between image one and two. Where'd all that data go?
So, then we add a polarizer to the other stream to 'erase' the which way information and restore the interference pattern.
But look at the numbers again! All we've done is remove more data to return the interference pattern just on a smaller scale.
My question is this: How is this in any way demonstrating quantum properties?
This looks like how to do tricks with statistics using polarizers on your data. What does this have to do with entanglement?
All images taken from: http://laser.physics.sunysb.edu/~amarch/eraser/
Edit: A quick summary of the quantum eraser experiment:
- A quantum entangled pair is split and sent to two detectors (A and B) and a coincidence circuit.
- B is a double slit experiment before the circuit. (produces image one)
- Opposite quarter wave plates are put in front of each slit to restrict only one type of polarization on the entangle particle from getting through the slit. This is now "marked path" and produces image two.
- A polarizer is put in front of A to restrict some more particles. This is now "erased" and produces image three.
It's possible my interpretation of what a polarizer is doing is different than yours so if there's any confusion check the page I linked or the wiki for Quantum Eraser experiment.
Edit 2: To restate the problem: Does the interference pattern created in the double slit experiment contain the non-interference pattern when which-way information is present and further contain the interference pattern when which-way information is "erased"?
Or, are these completely different data sets?