What is Epr: Definition and 121 Discussions

The EPR is a third generation pressurised water reactor design. It has been designed and developed mainly by Framatome (part of Areva between 2001 and 2017) and Électricité de France (EDF) in France, and Siemens in Germany. In Europe this reactor design was called European Pressurised Reactor, and the internationalised name was Evolutionary Power Reactor, but it is now simply named EPR.
The first operational EPR unit was China's Taishan 1, which started commercial operation in December 2018. Taishan 2 started commercial operation in September 2019. The first two EPR units to start construction, at Olkiluoto in Finland and Flamanville in France, are both facing costly delays (to 2022 and 2023, respectively). Two units at Hinkley Point in the United Kingdom received final approval in September 2016 and are expected to be completed around 2026.EDF has acknowledged severe difficulties in building the EPR design. In September 2015, EDF stated that the design of a "New Model" EPR was being worked on, which will be easier and cheaper to build.

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  1. Bob Walance

    I Many Worlds, EPR and ER=EPR

    This question is not intended to invoke arguments about whether Hugh Everett's theory, now referred to as the Many Worlds Interpretation of Quantum Mechanics, is feasible or not. When I heard David Wallace say that Many Worlds does away with the so-called 'spooky action at a distance' referred...
  2. E

    B How does the EPR paradox work?

    Hi, I've heard about the EPR paradox as follows: Leave two entangled particles A and B carried by scientists A' and B', with a pair of incompatible properties (eg spin up/down and left/right) in possible Green/Yellow and Blue/Red states. If one measures Yellow state (eg, particle B in spin up...
  3. Narayanan KR

    Interesting Links Between Faraday's EM Induction and EPR

    Imagine a magnet moving up and down so that its flux 'B' cuts the copper rod to produce an alternating emf, suppose if the movement is fast enough such that its frequency equals to the electron spin resonance frequency given by F = B x 2.8 Mhz per gauss, neglecting skin effect, more copper...
  4. B

    What is the role of local realism in quantum mechanics?

    I studied at UBC, U of Leiden, in quantum statistical mechanics and kinetic theory. I worked in chemistry at McGill University for many years doing the theory of NMR which involves spin theory. In 1997 I gave up NMR and started to study the EPR paradox. I do not follow the party line because I...
  5. Buzz Bloom

    I EPR Paradox: Exploring Uncertainty & Experimental Results

    While I have have heard about it for years, I have just read a more-or-less clear description of the EPR "paradox" in David Lindley's Where Does the Weirdness Go? (1996), page 91, "The fatal blow?". Here is a summary (paraphrasing what I read) as I understand it. A pair of particles (say A and...
  6. B

    I What is the paradox in the EPR paradox?

    Hi Which of these understandings is correct ? A stationary particle separates into 2 particles A & B Is it that : (a) One can independently measure accurately to the desired accuracy the momentum of A and the position of B and thus obtain both position AND momentum of either particle thus...
  7. bhobba

    I EPR and Non-Locality - For and Against

    Hi As most people I think know I do not think that QM requires non-locality of any kind. The reason is it is a limiting case of QFT which since it combines SR and QM it can not violate the assumptions it is built on. Specifically we have the cluster decomposition property...
  8. K

    I Effect of inserting an analyzer loop in the EPR experiment

    Given an EPR experiment such as the Alain Aspect 1982 test of non-locality using photons; if you modified the experiment so that the entangled photons first go through a analyzer loop (polarizer + inverse polarizer) before going to the polarizers in the experiment would you still see a non-local...
  9. T

    I Imagining the EPR paradox/quantum entanglement

    Dear community, I frequently have problems imagining the EPR paradoxon, hence how I can imagine entangled states. Let's say we have the Bell state of the basis /0> and /1>: Ψ = 1/√2 (\00>+\11>), where the first element of the ket belong to particle/qubit 1 and the second element to...
  10. K

    I Thermal interpretation and EPR experiment

    [Moderator's note: Thread spun off from previous thread due to topic change.] The thermal interpretation of the double slit experiment is very appealing alternative explanation to the Bohmian interpretation as I understood it from these discussions...
  11. G

    I Does EPR definitely rule out locality?

    Hi, Translated from German magazine "Spektrum der Wissenschaft", September 2009, p. 33 (original see below): That doesn't sound right. EPR even have "physical reality" in the title, though they might not mean with it the exact same thing as Bell. Why would we need Bell's argument if EPR...
  12. Lars278

    I Sending a cryptographic key faster than the speed of light

    Quantum entanglement does not imply that you can send information faster than the speed of light since you cannot manipulate what your sending. You don't know what you have until you have measured it. But you do know that you have the corresponding photon at the other location in space no matter...
  13. nomadreid

    I ER=EPR baby steps: causation or not?

    The questions concern the extension of the holographic principle to the identification of a wormhole between two black holes with negative cosmological constant and an entangled pair on its boundary, included in the conjecture known as EPR=ER ( Maldacena, Susskind). I refer to...
  14. A

    B What tells us photons were ever in a superposition in EPR

    Hi, I know that entanglement is real and that it tells us something profound about the nature of quantum objects like electrons and photons. I can't explain to a family member how we know that two twin photons in the EPR experiment started off in a superposition. In other words, how do we know...
  15. K

    B Does the EPR experiment imply QM is incomplete?

    I know this has been discussed in so many ways on this forum, but it is hard for me to separate interpretations, fact, speculation, and inaccuracies. You can probably just skip the next two paragraphs that I describe the EPR/Aspect experiment and go right to my question. In an EPR experiment...
  16. N

    I Can Quantum Entanglement Be Used to Transfer Information?

    We've just gone over the EPR paradox in class and I'm not really satisfied by the explanation of the professor and TA. Firstly, with the example of the two spins, I still don't see why measuring one spin and then knowing the other one doesn't count as information traveling faster than light...
  17. K

    B Preserving causality in the EPR experiment

    I have previously posted Preserving local realism in the EPR experiment . I have since given up on simulating local realism since I now understand it is impossible. However I have not given up on causality. Attached is code that simulates the EPR experiment and gives the same result as what...
  18. Mentz114

    I Can Exact Joint Probability Distributions Predict Violations in CHSH Tests?

    I've spent some time setting up my simulation of a photonic EPR experiment and came up with an exact joint probability distribution for the outcomes ##P_{xy}(\alpha,\beta)##. To calculate the CHSH number we need the probability of a coincidence for each of the possible settings which becomes a...
  19. K

    B Preserving local realism in the EPR experiment

    What is wrong with the idea that the spooky correlation in the EPR experiment is simply the result of the initial difference in rotation between the two polarizers in this experiment? So if you rotate one of the polarizers relative to the other polarizer, that initial act of rotation is what...
  20. R

    Understanding Bell's Theorem: An Introduction to the EPR Paradox

    Hi All, I am brand new here, still trying to navigate the website so please forgive me if this is not the appropriate space for the following. I missed the recent topic, "How do you understand EPR & Bell's Theorem? " No new threads permitted now but I would like to express a summary view as my...
  21. B

    I How do you understand EPR & Bell's Theorem?

    This is related to vanhees71 statements (see bottom). I'll explain. First. The idea is very simple. As summary: Einstein showed that if reality was objective and quantum theory complete, then there had to be nonlocal effects. But since nonlocal effects can violate relativity, then there had to...
  22. K

    B Photon detection in the EPR experiment

    In the photon version of the EPR experiment, how is the final polarization state of the photon detected? I have read a number of high level descriptions of the EPR experiment, but I am having trouble with understanding the detection part. Here is my understanding, please correct me where I am...
  23. PGaccount

    A Bohr's solution to the EPR paradox

    First, I will give my understanding of Bohr's resolution using an example that Bohr considers in his discussion. Then I will quote a passage where Bohr summarizes his resolution of the paradox. Finally, I will try to respond to John Bell's comments on this resolution. I would be interested in...
  24. C.Braestrup

    Microwave transparent material for ESR/EPR spectrometer

    Hi! Completely forgot about this great forum! I'm designing an electron spin resonance /electron paramagnetic resonance spectrometer, as an easier vacation from my diy NMR - while still utilizing much of the same setup. Issue is; I have an X-band (~12GHz) waveguide cavity in a magnet, and I...
  25. victor94

    I Exploring the EPR Paradox: What Does "Simultaneous Reality" Mean?

    I'm reading the paper of the EPR paradox and I'm confused in the meaning of this: "The elements of the physical reality cannot be determined by a priori philosophical considerations, but must be found by an appeal to results of experiments and measurements......when the operators corresponding...
  26. edguy99

    I Modeling EPR - Local or Non-Local

    One way to talk about it precisely is in your program (great program btw). When running the program, you clearly demonstrate a difference in correlation when only "local" vs. "non-Local" variables are used. In order to help understand your program, I have modified some defaults on the program...
  27. Old Chinaman

    B Understanding the EPR Paradox - Exploring the Gamma Factor

    I am not a physicist but interested in the decade long debate between Einstein and Niels Bohr, especially in the philosophical implication of the EPR Effect. I've been wondering if anyone could explain why Einstein, Podolsky and Rosen didn't applied the Lorentz Transformation formula - the...
  28. arupel

    I Explanation of the EPR paradox

    I am not sure I understand exactly what was the situation was with the EPR paradox Example: for simplicity: two electrons are coupled. One with spin up and the other with spin down. Since they are coupled there are one state. Separate the electrons one in one galaxy and the other in another...
  29. stevendaryl

    I Amplitudes, Probabilities and EPR

    Please read this Insight here: https://www.physicsforums.com/insights/quantum-amplitudes-probabilities-epr/
  30. A

    I Uncovering the Conceptual Catch in EPR Proposal for Non-Commutative Variables

    I question whether there would be a conceptual catch in EPR proposal to get both non commutative variables define with accuracy at one location simultaneously. The idea of separability that EPR introduced to questioning the completeness of QM is that whenever one measures a physical variable q...
  31. G

    I Why the tensor product (historical question)?

    Hi. Why did the founding fathers of QM know that the Hilbert space of a composite system is the tensor product of the component Hilbert spaces and not a direct product, where no entanglement would emerge? I mean today we can verify entanglement experimentally, but this became technologically...
  32. LoveQM

    I How did Einstein see that Entanglement lead to Connectedness

    I am studying the history of Quantum Mechanics and was reading about particle entanglement. What I would like to know is how did Einstein see that particle Entanglement meant that particles would be affected by spooky action at a distance. I guess that spooky action at a distance may also be...
  33. Dennis Plews

    I The information paradox and non-locality, ER = EPR

    I heard recently that Dr. Maldecena recently commented to Dr. Susskind, regarding the black hole information paradox, that ER = EPR. Can anyone illuminate this for us mere mortals? It seems to link all information via non-locality, which has interesting implications.
  34. G

    I Assuming nonlocal realism: What message would signal convey?

    Hi. I have a strange relation to Bell's inequalities, I understand (so I hope) all the maths but have lots of trouble with the implications of their violation. Currently: Say we assume QM to be realistic, it can't be local. There needs to be some sort of instantaneous signalling. Realism means...
  35. DrClaude

    A One-Way Quantum Steering Evidence: Quantumness Experiments

    Experiments provide evidence for one-way quantum steering—an effect by which distant entangled systems can influence one another in a directional way. http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.116.160403
  36. philton

    Exploring What If: ER = EPR and Gravitational Wave = Quantum Wave

    Homework Statement If ER==EPR Then IsPossible(gravitational wave == projection of quantum wave) In other words: If the conjecture of "ER = EPR" is true, is it possible that "gravitational wave = 3+1 dimensional part of quantum wave" is also true? 2. Homework Equations The quantum source...
  37. T

    Confused about EPR Thought Experiment

    In "Einstein's Moon" by F. David Peat there is a description of the EPR thought experiment,but I am confused by Bohr's response to Einstein given in Peat's book. In the EPR as described by Peat, particle A and particle B move in opposite directions after the entangled particle (AB)...
  38. T

    EPR paradox and time of collapse

    According to the EPR-paradox, if we have a pair of two entangled spin-1/2 fermions A and B and measure z-component of A, B collapses immediately as well(i'm using these letters for both particles and their observers). The 'canonical' solution is then to state that it is not possible to transfer...
  39. votingmachine

    Who would be interested in an EPR thought experiment?

    If a thought experiment with hidden variables gave the same results as EPR experiments, would that be a publishable (even if minor) contribution?
  40. T

    EPR & Bell: What's Wrong with My Scenario?

    What is wrong with my scenario? A traveler is about to embark on a mission to Mars. A technician is responsible for communications with the traveler. An entangled pair of electrons is prepared, one to make the trip to Mars and one to remain on Earth. When the traveler reaches Mars he changes...
  41. G

    What's the problem with (non-causal) nonlocality?

    Hi, In all the discussions about EPR, Bell's inequality and interpretations of QM locality seems to be a property that nobody likes to drop light-heartedly. This is somehow understandable since SR is an extremely successful theory. But SR only says that we cannot transmit information faster...
  42. U

    EPR Paradox: Entanglement & Opposite Spin Exploration

    The EPR paradox is often described this way: (from Wikipedia) A common presentation of the paradox is as follows: two particles interact and fly off in opposite directions. Even when the particles are so far apart that any classical interaction would be impossible (see principle of locality), a...
  43. stevendaryl

    Is there a connection between EPR and crossing symmetry in Feynman diagrams?

    This is sort of a nebulous question, but I'm wondering if anyone knows of analysis of the EPR experiment from the point of view of crossing symmetry for Feynman diagrams? In the above diagram, I've drawn a very simple particle interaction diagram. The same diagram can be interpreted in two...
  44. T

    Applying Bell's Theorem to Non-Photonic Entanglement

    This may seem like a silly question, but does Bell's theorem and the experimental design giving rise to the EPR phenomenon apply only to photons? Or could one, in principle, demonstrate this with entanglement of things with a rest mass, so moving at less than the speed of light? (I realize of...
  45. bohm2

    Einstein's later thoughts on EPR

    In re-discussing the EPR scenario in his autobiographical notes (1946), Einstein wrote: The first option (i.e. "telepathically changes the real situation") is just Einstein's unacceptability of non-locality as it goes against relativity but what does Einstein exactly mean by his unacceptability...
  46. jk22

    EPR paradox and prediction time

    If we suppose we have an entangled pair in position/momentum and, following the argument, we measure position of particle A. We get a result let say xA. Then we want to predict the measurement of position of B, so up to now we have not measured particle B, but we know it's wave-function is a...
  47. A

    Exploring EPR Spin & the Paradox of Measurement

    The epr paradox is usually explained as something like: Suppose you have two electrons in the singlet state (+=spin up, -=spin down): lψ>= l+>l-> - l->l+> Now if you measure the spin on the first electron the explanation is (I think) that this collapses one electron onto l+> or l-> such...
  48. D

    EPR Paradox Confusion: Understanding the Violation of Locality and Uncertainty

    Hello, I've read through several sources about the EPR Paradox but I'm not sure I'm understanding everything. I know that: -the paradox in question seems to be due to a violation of the principle of locality -there is no useful transferred faster than c regardless of which axes the two...
  49. T

    Exploring Entanglement in an EPR Experiment

    Hi, I have this one boggling my mind for quite some time. Let's consider a very simple EPR experiment -- pair of entangled particles are sent to Alice and Bob (separated by large distance), who (at the same time) measure its spin along different axis: Alice does the measurement on axis z...