What is Eraser: Definition and 123 Discussions

An eraser (also known as a rubber in Commonwealth countries, from the material first used) is an article of stationery that is used for removing marks from paper or skin (e.g. parchment or vellum). Erasers have a rubbery consistency and come in a variety of shapes, sizes and colors. Some pencils have an eraser on one end. Less expensive erasers are made from synthetic rubber and synthetic soy-based gum, but more expensive or specialized erasers are made from vinyl, plastic, or gum-like materials.
At first, erasers were invented to erase mistakes made with a pencil; later, more abrasive ink erasers were introduced. The term is also used for things that remove marks from chalkboards and whiteboards.

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  1. I

    Delayed choice quantum eraser experiment in terms of MWI and/or BI

    I'm sure there's been a lot of posts on this before, but even after taking a look at some of them, this experiment is still eluding my understanding. I'm aware that there's no backwards causation--and that the eraser causes interference by random 'categorization'--but I'm nonetheless...
  2. thenewmans

    Quantum Eraser and Delayed Choice Quantum Eraser

    I have read that these experiments have been successful and do not cause a disagreement with QM. But I can’t quite determine what was learned. So what did they prove or disprove? Is there a simple explanation? I thought they were designed to determine if wave collapse breaks either locality or...
  3. S

    Question about delayed choice quantum eraser

    I was reading about the Delayed Choice Quantum Eraser experiment here: bottomlayer.com/bottom/kim-scully/kim-scully-web.htm In this experiment the which-path info is erased or not at random AFTER the original (signal) photon hits the screen. The results of the screen are seen by the...
  4. J

    Uncovering the Science Behind Erasers: Why Do They Only Work for Pencil Marks?

    How does an eraser (rubber, for non-US) work? Any why it works only for pencil(or graphite) , not for pen?
  5. M

    Coincidence and Single Rate detection in Quantum Eraser experiments

    I am having difficulty understanding why the single rate of detection (as opposed to the coincidence rate) is unaffected during Quantum Eraser experiments. I'm looking at the great Kwait, Steinberg and Chiao paper: 'Observation of a "quantum eraser": A revival of coherence in a two-photon...
  6. I

    Is Timeless Light the Key to Understanding Quantum Eraser Experiments?

    The paper described at http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser rather intrigues me. While the results appear counter intuitive to us, the properties being tested are those of light, and since light travels at speed c, is it not the case that for light time stands still...
  7. I

    Can a lens act as a quantum eraser?

    I am just starting to study quantum mechanics, so I realize I am working with over-simplified examples, but that should work out since I'm hoping for simple answers... Among other things, the claim that this eraser would work has me scratching my head...
  8. K

    Exploring Using LIGO as a Photon Buffer for Quantum Eraser Experiments

    Just a few questions for anyone. I am trying to buffer photons for a long delay quantum eraser. Is there anyway to convert one arm of a 4km LIGO interferometer into a high-fidelity photon buffer? If a beam is merely reflected once down the length of the tube, it is stored for ~13 µs with...
  9. ZapperZ

    VOTE Photo Contest - Rubber Eraser

    Considering how quirky the theme is, we have a very good group of pictures for this contest. Please vote for the picture that best represents our theme - Rubber Eraser! 1. Chi Meson 2. scorpa 3. Physics is Phun http://img263.imageshack.us/img263/4233/img2695pm1.jpg 4...
  10. ZapperZ

    PF PHOTO CONTEST - Rubber Eraser (4/14-4/20)

    Rubber Eraser This is silly enough, and trivial enough, that I just HAD to include it in our contest. April 15 is, get this, http://www.holidayinsights.com/other/rubbereraserday.htm" here in the US! Honest! You can't make these things up! So, to mark this joyous occasion (and yes, I'm trying...
  11. S

    Can Extending the Delay in a Quantum Eraser Experiment Alter Past Events?

    Question: What would happen if this was delayed even further? We are talking nanoseconds here, but what if the particle was slowed or sent far away, before being reflected back? What I'm getting at is... What if the delay wasn't nanoseconds, but seconds? What if it was minutes? What if it was...
  12. T

    Designing a Motorized Chalk Eraser to Reduce Effort

    well,im thinkin of designing an eraser,specifically the conventional chalk eraser, that can act like a vacuum cleaner,in the sense that i would have to put a motor in it,for the reason that the user would have to use a lesser effort for him to erase something,nd no chalk dust...well u could say...
  13. C

    Delayed choice quantum eraser question

    I have a question about the delayed choice quantum eraser with the double split experiment. Forgive me if this is a silly question.I have seen the following: TEST 1 1. shoot the particles & measure the result 2. erase the result 3. check the wall (whatever you shot the particle at) = wall...
  14. B

    Delayed Choice Bell-state Quantum Eraser

    http://www.joot.com/dave/writings/articles/entanglement/spookiness.shtml http://www.joot.com/dave/writings/articles/entanglement/quantum-eraser.png 1. a laser fires photons into a Beta Barium Borate (BBO) crystal; 2. the crystal entangles some of the photons; and then 3. entangled...
  15. D

    Magnet Strength & Computer Safety: Debating Teslas

    Magnetic Eraser? Hi, My friend and I were arguing about this the other day and I wanted some input from you guys: How many teslas would it take to potentially harm a computer. In the lab we use a .155Tesla magnet to move encased objects around in our rutherford scattering lab. I said that...
  16. M

    Really delayed choice quantum eraser

    I am a High School Senior in Advanced Physics Topics class. We have recently deiscussed the basic double slit experiments and ways of quntum erasing and delaying choices, and how those situation affect the outcome of the screen whether it will show an interference pattern or not. We then...
  17. K

    Eraser sliding down slope - Friction

    An eraser slides down a slope of height 1m that makes an angle of 35 degrees with the ground. It takes the eraser 1,8s to do this. Find the coefficient of friction. I have no clue how to do this. I've not been able to solve any of the equations I've tried, because there is always the mass of...
  18. Whitestar

    Time Travel: Quantum Eraser Experiments

    Quantum mechanics has actually shown thru the quantum eraser experiments that we can rewrite the histories of photons, and that time is symmetrical. The best example of this is the translational interaction or pilot wave theory, where a particle future and particle past selves our in constant...
  19. E

    Delayed quantum eraser with double slit

    Hello all, I saw this setup for a quantum eraser: http://grad.physics.sunysb.edu/~amarch/PHY5656.gif In this setup, we get no interference: http://grad.physics.sunysb.edu/~amarch/PHY5658.gif Then, by inserting a polarizer we can erase the which way information: Setup with...
  20. S

    Can Quantum Eraser Experiments Predict the Future?

    I have been contemplating this experiment for quite some time now, and I have some questions. http://xxx.lanl.gov/PS_cache/quant-ph/pdf/9903/9903047.pdf is a preliminary copy of the paper describing the experiment, for reference. The first and most obvious question would be whether it is...
  21. N

    More thoughts on quantum eraser experiments

    Patrick posted the following interesting link in another thread: I'd like to discuss this some more. Whenever I have read about these experiments I have always hoped to see the results of one in particular but I have never found what I wanted. I can guess what the results would be, but...
  22. V

    Where Can I Find the Original Quantum Eraser Study by Scully and Druhl Online?

    where can i get an online copy of the original paper of Scully and Druhl ( about the quantum eraser experiment) ? and any other good material on the topic . also where can i get something about Popper's experiment? please help.
  23. P

    Questions about Delayed-Choice Quantum Eraser

    I was reading about Scully and Druhl's delayed-choice quantum eraser in Brian Greene's Fabric of the Cosmos today and I had a couple of questions that maybe you guys can help me with. As I understand the idea, in one type of this of experiment a photon is fired(?) to a beam splitter the...
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