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Acceleration by the Casimir effect: violation of relativity?

  1. May 26, 2004 #1
    There exist shapes of particular materials that self-propagate in vacuum due to the Casimir effect. Such an object would use vacuum polarization to accelerate relative to other, quasi-inertial objects. Does this absolute motion disagree with relativity, or might it relate to the blackbody background?
     
  2. jcsd
  3. May 27, 2004 #2
    What materials and shapes would that be?
     
  4. May 27, 2004 #3
    I guess asymmetric, atomic-sized conductors.
     
  5. May 27, 2004 #4

    russ_watters

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    Well hold on - there is a big difference between "there exists" and "I guess." Has anyone ever demonstrated this?

    It sounds suspiciously like a misunderstanding of pressure/buoyancy to me...
     
  6. May 27, 2004 #5
    It happens. It is due to zero point energy between two conductors at a certain distance and of a certain size. At certain distances ZPE somehow 'takes over' and attraction occurs. Also known as vacuum energy it is what is thought to be making space expand. Do google for zero point / vacuum energy

    K_
     
  7. May 27, 2004 #6
    Consider the empty vacuum. Place within it a spherically asymmetric conductor (an ovoid, say) of atomic dimensions. The vacuum polarization upon the object's quantum-scale surface biases the overall Casimir force as significantly noninertial with respect to averaged vacuum fluctuations, in possible disagreement with relativity. When compared to a similar object, mutual gravitation diminishes greatly with distance as opposed to the original scalar Casimir effect, which balances out cosmological spacetime curvature.

    Can the Casimir effect concur with relativity in this manner?
     
  8. May 27, 2004 #7

    russ_watters

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    Yes, I know about the attraction due to ZPE - but that's symmetrical and not what we're talking about here.
    But has this actually been done?
     
  9. May 27, 2004 #8
    To my knowledge, only as a Gedanken experiment. (Those Casimir calculations, even seemingly simple ones, are intractable.)
     
  10. May 28, 2004 #9
    Could you post us a link to that gedanken experiment, please?
     
  11. May 28, 2004 #10

    russ_watters

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    "Gedanken" is German for "thought." This is the problem with thought experiments: they are only meaningful if you understand the science behind them - its not just a matter of what your intuition says should happen.

    Looren Booda, I don't see any reason why vacuum energy would behave any differently than pressure on irregularly shaped objects. A common misconception brought out in 1st semester fluid mechanics courses is whether pressure is different on different sides of an irregularly shaped object (ie, can you have a net force on the object): It isn't.

    A similar misconception is concentration of pressure. If you take a tall, wide vessel or hydraulic cylinder, can you concentrate the pressure at the bottom by funneling it into a small tube (at the same height as the bottom of the vessel)? Answer: no.
     
    Last edited: May 28, 2004
  12. May 28, 2004 #11
    The question as I see it is, is there a suitably shaped and sized conductor which being near the quantum level undergoes a disequilibrium of forces not due to classical mechanics, but to its irregular constructive/destructive interference of quantum fluctuations, thus possibly contradicting relativity.

    The thought experiment is my own.
     
  13. May 28, 2004 #12
    The question as I see it is, is there a suitably shaped and sized conductor which being near the quantum level undergoes an inertial disequilibrium of forces not due to classical mechanics, but to its irregular constructive/destructive interference of quantum fluctuations, thus possibly contradicting relativity.

    The thought experiment is my own.
     
  14. May 28, 2004 #13
    The question as I see it is, is there a suitably shaped and sized conductor which being near the quantum level undergoes an inertial disequilibrium by forces not due to classical mechanics, but to its irregular constructive/destructive interference of quantum fluctuations, thus possibly contradicting relativity.

    The thought experiment is my own.
     
  15. May 28, 2004 #14

    TeV

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    Here's the error in the line of thought I guess.
     
  16. May 28, 2004 #15

    russ_watters

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    I understand, but...
    Well, fine - my thoughts are different from yours. Are we at an impasse? I don't think so.

    A thought experiment, if it hasn't actually ever been performed in reality should conform to the logic and constraints of existing theory, not just personal intuition (or wishful thinking?). Existing theory suggests such a shape does not exist.

    This is an eye-opener to me. This may be the root cause of a lot of the problems we have with thought experiments on this board. It may simply be that people are assuming they can have whatever outcome they want since the experiment exists only in their head. Not so.
     
  17. May 29, 2004 #16
    Let me put my original premise this way: can the Heisenberg uncertainty principle disagree with Einstein's principle of equivalence, i. e., can a noninertial frame for a quantum object arise from local vacuum fluctuation action alone?
     
  18. May 29, 2004 #17
    Concerning a mental experiment (Gedanken), I invit you to read mine on this forum: Physics = only math? I just suggest that fluctuations (for example EM) occur exactly in the same mathematical space than Laws of the GR are defined and valid because there is only one world... It is for me a good reason why, with work and patience, we should be able to find a connection between Quantum Theory and GR in this world. Blackforest
     
  19. May 29, 2004 #18
    The HUP is gauged as a Local Effect, if one gets pretty close to a particle during observation (assuming observation is 'Locating' the Quantities that define a particle!), then you forsake one measurable quantity against the other.

    You know that a Particles momentum is not in the same vicinity of its position if 'YOU'(detector) are Relative to either!

    The simple fact of the matter is YOU cannot be in Two places at any instant, which is the factor needed to measure with a high degree of accuracy a particles two most previlent features, the features which determine its existence.

    Now the question you pose above needs further investigation if one make this statement: If you could be in two locations at any instant, are you Relative to yourself?..how could your Acceleration be determined if you stand on Earth, and at the same instance be at a Blackhole Horizon of a far off distant Galactic formation just after the Big-Bang!

    Think about it :rolleyes:

    Think about the dimensionality of curvature, and the dimensionality of non-curvature SpaceTimes?..the route of information needed to Locate any 3-D object is 'NOT' the same for a Flat 2-D field.

    3-Dimensional objects are by defination located with a Boundary, they have definate paramiters which give them real spacetime definations.

    2-Dimensional Fields are by defination 'Everywhere', Boundary free!

    A 3-Dimensional object can sit within a 2-Dimensional Field, if another 3-Dimensional object exists in the Same field, then they can be referenced.

    The problem is that a 2-Dimensional Field 'CANNOT' exist within a 3-Dimensional Object. This needs a perceptional journey to get around the obvious paradoxes, but like I said a 2-D field extends without Boundaries, it is infinite, so cannot be constrained by a Finite 3-D object.

    The simplistic value of this is contained within SR and GR, a lesson in EPR was used to show the QM community, E-P-R failed to convince them :smile:

    I'm editing this post because of the obvious content of Lorens Question, so lets see if we can advance a little further?

    Question: Can 3-D energy appear out of an infinite 2-D field? and is there a comparable action for a 2-D field appearing out of a 3-D object?
     
    Last edited: May 29, 2004
  20. May 29, 2004 #19

    TeV

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    I don't see in what way HUP can disagree with the equivalence principle of GR.Seeking for the effects arising from QM,that would reveal incompletness of QM, Einstein himself imagined a serie of thought experiments.Once he came to Bohr in triumph showing him thought experiment he considered to be in disagreement with his theory.Einstein couldn't find a flaw.But next day,Bohr find the flaw using the very same GR equations (!),showing there was no inconsistencies.Einstein was shocked.Afterwards he admited he didn't know Bohr knew the core of GR so well.
     
  21. May 29, 2004 #20
    Olias
    There are quantum gravity models that seemingly can only be solved in two spatial dimensions.

    J. A. Wheeler says "the-one dimensional boundary of the two-dimensional boundary of a three-dimensional space is zero."
     
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