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The Quantum Time Machine

Quantum processes seem to allow for "programming" operant particles into a time point previous to the operation. And the grandfather paradox doesn’t apply:

Scientists have for some years been able to ’teleport’ quantum states from one place to another. Now Seth Lloyd and his MIT team say that, using the same principles and a further strange quantum effect known as ’postselection’, it should be possible to do the same backwards in time. Lloyd told the Technology Review: "It is possible for particles (and, in principle, people) to tunnel from the future to the past."

Published in researchmaterial


  1. i don’t know..if time travel does exist,especially in the future then why hasn’t there been any reason to fix the past??

    Also,nothing dramatic has changed-especially with events that have already happened-unless those events were meant to happen to push time forward allowing a bubble of time in which to travel back and forth..

  2. Jesse


    I’ll believe it when I see it.

  3. This all works fine, until the undergraduate student in charge of setting up quantum states and sending them back in time has a messy weekend, sleeps in on Monday morning, and accidentally destroys history by missing the bus.

  4. tobot


    so in a simplistic sense you could have binary yes/no quantum particles set up and send yes/no answers back in time.

    these guys are going to be stinking rich and/or dissapeared

  5. I’d queried a few physicists I know about this one already, and I’ll quote Dave Bartram on why this doesn’t work:

    ?”Postselection can only occur if quantum mechanics is nonlinear, something that seems possible in theory but has never been observed in practice. All the evidence so far is that quantum mechanics is linear” is basically the key point.

    These guys have, I expect, added a nonlinear term to the Schrodinger equation because interesting and fun things happen when you do that. I’ve seen research like that before – it’s interesting, but has no bearing on the real world until we get evidence that quantum mechanics may actually be nonlinear.

    So it’s basically saying “if there are magical terms in the Schrodinger equation for which we have no evidence, then time travel!”.

    As the article states, a lot of people take the wacky conclusions that nonlinear quantum mechanics predicts to be a strong sign that the real Schrodinger Equation doesn’t have any nonlinear terms.

  6. Owen


    Something I’ll definitely have to see first to believe, mailing me Stalin’s mustache will be proof enough. Also, c’mon, why is everyone focusing on teleportation and time travel? Multiple realities is where it’s at.

  7. Bernardo


    Actually something like time travel is already possible, the effect post selection is very interesting (if not fucking batshit insane). John Wheeler’s “delayed choice” has been recently done and proved (it was a thought experiment originally).

    Basically is a two slip experiment, for clearness sake it works like this: you pass a photon or other elemental particle through a plate with two slits, if you see the plate you will notice that it has gone through both slits, like a wave, but if you see the slits you will see the photon just going through one, like a particle.

    Wheelers’ experiment works like this, you put a removable wall farther from away from the plate and behind the wall you put two “telescopes” (or something optical) and each telescope is just watching one slit, so if you watch the wall you can see a wave pattern (the photon went through both slits) but if you remove the wall and watch the telescopes you will see just one of them capturing light( hence the photon behaved like a particle) photon behaved like a particle. The experiment consists in beign able to get the wall out of the way after the photon has passed through the slits but after it hits either the wall or telescopes.

    if you leave the wall the photon behaves like a wave but if you remove it, it behaves like a particle, all of this after it has passed through the slits, so in effect the act of choosing which way you are going to observe the photon changes the photon retroactively. Now that is pretty fucking messed up.

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