dcqe Definition and 18 Threads

  1. R

    B Does DCQE show a shift between the two "which path" results?

    The Delayed Choice Quantum Eraser (DCQE) experiment attempts to show that which-path information can be "erased," and interference recovered. I'll refrain from explaining the experiment, and assume you are familiar with the setup. I refer to the Wikipedia page about it, and the original Kim...
  2. G

    Superdeterminism ruined the significance of DCQE experiment

    I keep thinking that the universe "knows" when, how, where these know-it-all (no pun intended) physicists did their experiment so all the results are not only consistent, but perfectly normal, nothing freaky about it. I'm no longer capable of thinking like a normal human being and subsequently...
  3. E

    B Why would non-locality solve the time paradox in dcqe?

    I've been trying to work out exactly what part of the experiment I'm fundamentally not getting. The experiment basically says that no information is being sent back in time because the coincidence counters are needed to isolate the signal photons and expose the interference pattern. But the...
  4. Derek P

    I Kim et al DCQE optical details

    I am (still) trying to understand the optics of the Kim et al DCQE set-up. It is the optics of the "erased" cases that I don't understand. These are the entangled pairs where the "idler" photon is detected by D1 and D2. Each detector receives a contribution, from one slit, that has passed...
  5. TJung

    B Double slit and DCQE with future prediction

    Tom Campbell posted a series of videos in youtube where he proposes a few variation of double slit and DCQE experiments that might support his theories. He claims that would be possible to predict a future atom decay or a beam splitter behavior that way. I am very interested about experiments...
  6. M

    Is DCQE erasing information or resetting the system?

    TL;DR I want to warn readers (non-physicists) of my blog that it is wrong to claim that erasing or not detecting "which-path" information in DS and DCQE experiments is the same as turning off your recording device or deleting a data file on your PC, and it is wrong to assume that the particle...
  7. D

    DCQE Question on Purpose of Glan Thompson Prisms

    I have a question regarding Kim et al DCQE experiment: http://arxiv.org/pdf/quant-ph/9903047v1 (also found at wikipedia.org). I have seen a number of (very) different schematics of the experiment. The best one reviewed by Dr. Kim is at: bottomlayer.com/bottom/kim-scully/kim-scully-web.htm...
  8. D

    Can Single Photon Measurements Reveal Quantum Interference or Particle Behavior?

    I'm not a physicist, but have been thinking about these test lately and have hit some roadblocks that should be answerable. 1. Why can't we measure a single photon to determine if it fell into the interference pattern or acted as a particle? I understand this is because I'm thinking of two...
  9. S

    Entanglement in delayed choice quantum eraser (DCQE)

    In the delayed choice quantum eraser (DCQE), such as the walborn paper, link below: http://arxiv.org/PS_cache/quant-ph/pdf/0106/0106078v1.pdf" we try to find out the polarization/path via quarter wave plates (see diagram on page 7 of the paper) Now does not entanglement break (i.e...
  10. S

    Understanding which-way patterns in DCQE

    Figure 3 of the below shows 1 blob. http://www.fsc.ufsc.br/~lucio/2003-07WalbornF.pdf Other illustrations show 2 blobs...i.e. one for each slit. When does 1 blob happen and when does two blobs happen?
  11. S

    Explaining DCQE - via coherence in layman terms

    Does the below sound ok? 1. Interference is caused between coherent waves 2. When we try to find which-way we break the coherence a) When we try to "partially" find which way, we partially break the coherence and hence a "partial" interference pattern 3. DCQE is explained by the fact...
  12. S

    DCQE - walborn/yoon do it one way only

    the experiements first do which-way on the s-photon and then use eraser on the p-photon (after s has been registered on the detector) and then get interference pattern (via pairing from coincidence counter) now let’s say we do no-which-way on the s-photon and then use marker on the...
  13. S

    DCQE - how does/can the pattern change?

    in DCQE - Delayed Choice Quantum Eraser such as the one listed here -----> http://grad.physics.sunysb.edu/~amarch/ let's say we know which-way for s photons...thus we should get two columns/bands of dots...one for each slit...a Zero interference pattern...and it would look like...
  14. S

    In DCQE you can get which way and still get interference?

    in DCQE you can get which way and still get interference? for example when the s-photon strikes the detector ...let's assume setup is such that which-way is known now we send the idler via erasure (after registration of s) and later when we sub-sample via co-incidence counting we get...
  15. S

    DCQE - inserting eraser after s is detected

    In the below experiment the eraser is in the path of p-photon before s is detected. Then s is detected and then p photon encounters the polarizer and then Dp. If we were to insert the polarizer after s is detected, would the pattern/results change? relative to just keeping the polarizer in the...
  16. S

    DCQE - Why don't we get idler pattern?

    In the delayed choice quantum eraser such as one described in the Kim paper... http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraserWe have five detectors D0, D1, D2, D3, D4 and D5 The signal photon strikes the detector D0. Please note this discussion is more focussed on the idler and...
  17. S

    Optimizing the DCQE: BBO Placement and its Impact on Experiment Results

    In the DCQE such as the one referenced below: 1. The beta barium borate crystal (labeled as BBO) is placed after the double slit Would the experiment still be the same if we place the BBO before the double slit and have the "signal" photon then proceed directly to Do without having to go...
  18. S

    Idler behavior post signal detection in DCQE

    Refer to the delayed choice quantum eraser (DCQE) ...for example the kim paper http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser" i have a few questions, to understand this better, 1. Once the signal photon has been detected at D0, can the path of idler photon be...
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