Is Time Travel Possible with Entangled Particles?

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    Entanglement Relativity
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Discussion Overview

The discussion revolves around the possibility of time travel using entangled particles, exploring the implications of quantum entanglement in the context of relativistic speeds. Participants examine the correlation of measurement results between entangled particles and the effects of relativistic time dilation on these measurements.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant describes a scenario involving two entangled particles, one on a spaceship and the other on Earth, and proposes that measurements taken at different times could lead to contradictory results based on the measurement states chosen.
  • Another participant questions the validity of the proposed scenario, asserting that changing the measurement state on one particle should not allow for faster-than-light (FTL) communication, as it violates the principles of quantum entanglement.
  • A different participant argues that the measurements are spacelike separated, meaning they do not have a definitive time order, and thus one measurement cannot be said to affect the other.
  • There is a suggestion that the outcomes of the measurements will still follow quantum mechanical predictions, regardless of the order of measurements, and that the correlation between them is determined by the entangled state rather than the sequence of measurement.
  • One participant proposes a scenario where the spaceship moves at a slow speed relative to Earth, questioning whether this would affect the time ordering of measurements.

Areas of Agreement / Disagreement

Participants express disagreement regarding the implications of measurement order and the effects of relativistic speeds on entangled particles. No consensus is reached on whether the proposed scenario leads to contradictions or if it aligns with quantum mechanical predictions.

Contextual Notes

Participants highlight the importance of the invariant nature of spacelike separated events and the implications for measurement outcomes in quantum mechanics. There are unresolved questions about the effects of varying speeds on the ordering of measurements.

  • #31
snuz2001 said:
So what is the answer? Can Bob’s late measurement affected Alice’s earlier?

Nobody knows the answer. At least one QM interpretation, retrocausality, allows later measurements to affect earlier ones. Nobody has found a way to experimentally test one QM interpretation vs. another, so as far as anyone knows retrocausality is still a possibility, at least in principle.

I know you would like there to be a definitive answer, but as has already been pointed out several times, this is one of those cases where we don't have one at our current state of knowledge.
 
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  • #32
The OP question has been addressed as well as it can be. Thread closed.
 

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