Spooky action at a distance gets spookier


Take a pair of entangled photons and perform a measurement on one of them. According to the strange laws of quantum mechanics, this measurement immediately influences the state of the second photon, no matter how far apart they are. Einstein bridled at the possibility that an instantaneous influence could take place. He called it spooky action at a distance and the term stuck.

Today spooky action at a distance just got spookier. Stephen Harris at Stanford University posts details of an experiment in which he zaps one photon in an entangled pair in a way that ensures that this photon is modulated.

But his extraordinary result is that after zapping the first photon, he can then zap the second photon in way that negates (or enhances) the modulation  of the first.

That’s not just spooky, it’s double spooky.¬† It opens up the possibility of a few neat new tricks such as pulse shaping photons at a distance. And it raises some interesting questions about the nature of entanglement and how it may come to be exploited in future.

Ref: arxiv.org/abs/0808.0903: Nonlocal Modulation of Entangled Photons

4 Responses to “Spooky action at a distance gets spookier”

  1. Tanath says:

    How is this not expected behaviour? This fits with the understanding I acquired of quantum theory as a teenager.

  2. Tim Rhoades says:

    I agree with Tanath, I don’t see the ‘new’ in this article. Could you explain what is different than expected?

  3. Rebel Dreams says:

    I think the “unexpected” aspect of this is that the modulation of the second photon does not appear to produce a bidirectional modulation of the first. With two modulators running (one per photon) the modulation becomes the product of both, suggesting that information can be inferred about the states of the two photons separately, even though they are part of the same system.

    Remember, these are non-time-degenerate photon pairs, meaning that under standard theory one should not be able to see any temptoral difference between the two; this experiment overturns that idea and suggests that there areat least *some* time-dependent behaviors in entangled systems, leading to the possibility of real modulated-frequency communications between entangled pairs.

  4. Zephir says:

    By AWT intepretation, the modulation of one photon establishes a spatial distribution of vacuum foam density (a sort of optical grid), which affects the another photons accordingly in analogy to Aharamov-Bohm effect. Such explanation still doesn’t require the exchange of energy by superluminal speed, I hope.

    The spatial change of vacuum density is nothing unusual in AWT. For example the action of magnetic field can be expressed in terms of space-time density gradient as well. Such gradient cannot be observed by using of light, because it deforms the time and space dimensions accordingly – but it still manifests itself by force gradient. We should realize, we cannot observe the changes in environment density by using of waves, if we are observing the wave spreading just by using of the same waves. This trivial insight forms the conceptual base of relativity understandig, by the way.