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Einstein's 'Spooky Physics' Gets More Entangled

  1. Jun 4, 2009 #1
    "Einstein's 'Spooky Physics' Gets More Entangled"

    I wanted to just prompt a discussion about what is happening in this interesting article.

    Does this mean the information channel is stable for multiple excitations? And can the channel carry classical information?

    Feel free to point out other interesting interpretations on this article.

    http://www.livescience.com/strangenews/090603-maco-entanglement.html
     
  2. jcsd
  3. Jun 4, 2009 #2

    DrChinese

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    Re: "Einstein's 'Spooky Physics' Gets More Entangled"

    Here is a link to the paper itself:

    Entangled Mechanical Oscillators

    Abstract:

    Hallmarks of quantum mechanics include superposition and entanglement. In the context of large complex systems, these features should lead to situations like Schrodinger's cat, which exists in a superposition of alive and dead states entangled with a radioactive nucleus. Such situations are not observed in nature. This may simply be due to our inability to sufficiently isolate the system of interest from the surrounding environment -- a technical limitation. Another possibility is some as-of-yet undiscovered mechanism that prevents the formation of macroscopic entangled states. Such a limitation might depend on the number of elementary constituents in the system or on the types of degrees of freedom that are entangled. One system ubiquitous to nature where entanglement has not been previously demonstrated is distinct mechanical oscillators. Here we demonstrate deterministic entanglement of separated mechanical oscillators, consisting of the vibrational states of two pairs of atomic ions held in different locations. We also demonstrate entanglement of the internal states of an atomic ion with a distant mechanical oscillator.
     
  4. Jun 4, 2009 #3
    Re: "Einstein's 'Spooky Physics' Gets More Entangled"

    But a mechanical oscillator has no superposition, no HUP - its a spring or similar. I don't understand how this can be entangled in the QM sense.
     
  5. Jun 4, 2009 #4

    f95toli

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    Re: "Einstein's 'Spooky Physics' Gets More Entangled"

    It is a resonator, there is no fundamental difference between this system an e.g. photons in a cavity; the basic Hamiltonian is the same. There is no reason why it wouldn't be possible to put it into a superposition.

    However, I must say the authors of this paper are "cheating" a bit by using ions. Ideally one should perform this experiment using two micromechanical resonators (i.e. literary two vibrating beams).
    Some research groups are already getting close to the point where they can put one such resonator in its ground state; and entanglement should follow quite soon after (my guess would be that it is 2-3 years away).
     
  6. Jun 4, 2009 #5
    Re: "Einstein's 'Spooky Physics' Gets More Entangled"

    I don't get it. Would a mechanical system pass the Bell test?
     
  7. Jun 5, 2009 #6

    f95toli

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    Re: "Einstein's 'Spooky Physics' Gets More Entangled"

    I guess that would depend on how well you manage to insulate it. Although mechanical systems might actually be easier in some ways to insulate than e.g. electrical systems (solid state qubits etc; where a Bell-type test is not far away) since they are phonon-driven meaning they can be cooled to very low temperatures. The main problem at the moment is that their eigenfrequencies are very low (at least for nano/micromechanical systems), usually in the MHz regime meaning they are too easily excited.

    Also, note that it would probably not be possible to peform a Bell-type test on two mechanical resonators; something more complicated would be needed since one need a couple of "knobs" that can tune the system and be used for state preparation; i.e. some tunable anaharmonicity is needed.
     
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