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Space-Time Cloak Could Hide Actual Events

Posted by samzenpus on from the out-of-sight-out-of-time dept.

An anonymous reader writes "My first thought was, a hypothetical space-time invisibility cloak? That must be what hypothetical crime-fighting Einstein wears when he wades into the fray! Sadly, the researchers who thought up this trick to 'hide events' say that the metamaterials we have on hand will only allow for a nanoscale demonstration at best."

4 of 129 comments (clear)

  1. Minkowski you bastard by Adambomb · · Score: 4, Insightful

    mwahaha! if i'm never a part of events intersecting the light cone i dont exist!

    oh shiii-

    --
    Ice Cream has no bones.
  2. And may I be the first to say by boogersniffer500 · · Score: 3, Insightful

    I'll believe it when I don't see it!

  3. Re:Better article by locofungus · · Score: 3, Insightful

    So, there is no magical disappearing of time or events or 4D cloaking of spacetime.

    It's slightly more subtle than that. IIUC, it's impossible to detect something happening in the cloaked region of space. So in the chicken crossing the road scenario, to an outside observer, it looks like the cars travel at a constant speed and the chicken "magically" teleports from one side of the road to the other.

    The idea that something is in one state or another without being able to detect intermediate states is not new to physics. If you attempt to "watch" the transition between two eigenstates you will always measure one state or the other. We can have a mathematical model of how the wave function evolves, we can do experiments that demonstrate that the wavefunction must have been in a state that our mathematical model describes as a superposition of eigenfunctions, but we can never measure that superposition.

    In QM terms, I suppose the chicken would be described as "tunneling across the road"

    (note that I have no reason to suppose there is any relationship between 4d cloaking and QM tunneling - it's merely an analogy that came to mind)

    Tim.

    --
    God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
  4. Re:Ffs by DJRumpy · · Score: 3, Insightful

    It's all relative. Actually it is sped up, but not in the way you think. They've found that if a gravity well is strong enough, it actually pulls spacetime around it. If you were to shine a beam of light while based on spacetime that is moving, you in essence create a beam of light that is moving faster than the speed of light, at least for an observer standing on spacetime that is not moving.