1. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    52619
    24 Mar '15 10:48
    A particle superpositioned with itself!

    http://phys.org/news/2015-03-quantum-einstein-spooky-action-distance.html
  2. Joined
    11 Nov '05
    Moves
    43938
    24 Mar '15 15:17
    Originally posted by sonhouse
    A particle superpositioned with itself!

    http://phys.org/news/2015-03-quantum-einstein-spooky-action-distance.html
    ""Spooky action at a distance" proven now:"

    But this is well proven from before, isn't it?

    "A particle superpositioned with itself!"

    But this is quite a new insight! A particle plays with itself!
  3. Joined
    31 Aug '06
    Moves
    40565
    24 Mar '15 16:20
    Originally posted by FabianFnas
    A particle plays with itself!
    And it's not ashamed about it? Clearly an atheist particle.
  4. Standard memberDeepThought
    Losing the Thread
    Cosmopolis
    Joined
    27 Oct '04
    Moves
    78621
    24 Mar '15 18:12
    Originally posted by FabianFnas
    ""Spooky action at a distance" proven now:"

    But this is well proven from before, isn't it?

    "A particle superpositioned with itself!"

    But this is quite a new insight! A particle plays with itself!
    There's the Alain Aspect experiment from the late eighties, but people argued with it. It's not clear to me from the phys.org article what they've done, phys,org where too busy talking about spooky action at a distance and didn't explain what the experiment actually did. Without reading the paper it's not clear to me what they've shown.

    If they've "proved Einstein wrong" it means they've ruled out hidden variable theories, so the deBroglie-Bohm interpretation is looking in trouble assuming phys.org hasn't misrepresented the experiment. This leaves the Copenhagen interpretation and the Many Worlds interpretation as the remaining viable candidates. There are other interpretations, but they are either hidden variable theories or rehashes of the Copenhagen or many worlds interpretations.
  5. Germany
    Joined
    27 Oct '08
    Moves
    3081
    24 Mar '15 20:20
    Theoretically there is nothing new here. It's just a novel (and pretty nice) experimental way of demonstrating it.
  6. Germany
    Joined
    27 Oct '08
    Moves
    3081
    24 Mar '15 20:23
    Originally posted by DeepThought
    There's the Alain Aspect experiment from the late eighties, but people argued with it. It's not clear to me from the phys.org article what they've done, phys,org where too busy talking about spooky action at a distance and didn't explain what the experiment actually did. Without reading the paper it's not clear to me what they've shown.

    If they've " ...[text shortened]... re either hidden variable theories or rehashes of the Copenhagen or many worlds interpretations.
    The e-print is available here:

    http://arxiv.org/abs/1412.7790
  7. Standard memberDeepThought
    Losing the Thread
    Cosmopolis
    Joined
    27 Oct '04
    Moves
    78621
    24 Mar '15 20:27
    Originally posted by KazetNagorra
    The e-print is available here:

    http://arxiv.org/abs/1412.7790
    Thanks, I'll give it a read.
  8. Standard memberDeepThought
    Losing the Thread
    Cosmopolis
    Joined
    27 Oct '04
    Moves
    78621
    24 Mar '15 21:50
    I've skim read the paper. I think this is mainly of technological importance. I don't think it alters the status of any of the interpretations of Quantum Mechanics. The homodyne measurement involves interference patterns between wavefunctions and, as I understand it, in de Broglie-Bohm the pilot waves (wavefunction) are meant to interact this way anyway the local presence of the particle isn't required for it to happen. They explicitly state in the discussion that it is not a Bell Inequality violation test. So I don't think that this does anything to rule out different interpretations of Quantum Mechanics.
  9. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    52619
    26 Mar '15 10:18
    Originally posted by DeepThought
    I've skim read the paper. I think this is mainly of technological importance. I don't think it alters the status of any of the interpretations of Quantum Mechanics. The homodyne measurement involves interference patterns between wavefunctions and, as I understand it, in de Broglie-Bohm the pilot waves (wavefunction) are meant to interact this way anyw ...[text shortened]... don't think that this does anything to rule out different interpretations of Quantum Mechanics.
    What do they mean by this statement:

    "We demonstrate this single-particle spooky action, for the first time with no efficiency loophole"

    What do they mean by 'efficiency loophole'?
  10. Standard memberDeepThought
    Losing the Thread
    Cosmopolis
    Joined
    27 Oct '04
    Moves
    78621
    26 Mar '15 19:57
    Originally posted by sonhouse
    What do they mean by this statement:

    "We demonstrate this single-particle spooky action, for the first time with no efficiency loophole"

    What do they mean by 'efficiency loophole'?
    I'm a theorist and this is an experimental detail, I'll do by best but this is something I don't have much intuition for, so this is the kind of thing I can misunderstand easily. The paper talks about Bob and Alice as two experimenters in separate labs. Some experiments require post-selection, I think what this means is that Bob needs information from Alice about which wavefunctions she's manipulated. The way they put it is that Bob needs to trust Alice to do the experiment properly. In this experiment Bob does not need to trust Alice to work out if a photon's had a homodyne measurement done on it. So there is no loss in (experimental) efficiency.
  11. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    52619
    27 Mar '15 22:13
    Originally posted by DeepThought
    I'm a theorist and this is an experimental detail, I'll do by best but this is something I don't have much intuition for, so this is the kind of thing I can misunderstand easily. The paper talks about Bob and Alice as two experimenters in separate labs. Some experiments require post-selection, I think what this means is that Bob needs information from ...[text shortened]... oton's had a homodyne measurement done on it. So there is no loss in (experimental) efficiency.
    Like not needing to introduce outside information beforehand?
  12. Standard memberDeepThought
    Losing the Thread
    Cosmopolis
    Joined
    27 Oct '04
    Moves
    78621
    28 Mar '15 02:21
    Originally posted by sonhouse
    Like not needing to introduce outside information beforehand?
    Well, this is after the fact information, as I understand what it means is that they didn't have to use careful timing tricks to make sure that the photon tinkered with by one observer was the photon the other observer did the position measurement on. It's easy for me to be wrong about this, the paper assumes various bits of background I don't have.
Back to Top