Quantum Entanglement and time travel

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Discussion Overview

The discussion revolves around the concept of backward time travel in the context of quantum mechanics and general relativity. Participants explore the implications of quantum entanglement, nonlocal interactions, and the nature of time as it relates to theoretical models of time travel.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants express skepticism about the possibility of backward time travel, citing paradoxes and the irreversibility of time as major concerns.
  • Brian Greene's comments on time travel are discussed, with some participants questioning whether he refers to quantum mechanics or general relativity.
  • There is a suggestion that quantum mechanics contains an irreversible component, which may complicate discussions about time travel.
  • Some participants argue that nonlocal interactions in quantum mechanics do not transfer information, raising questions about their implications for time travel theories.
  • One viewpoint emphasizes that backward time travel should not be thought of as "rewinding" events but rather as a looping of worldlines in spacetime.
  • Another participant argues that the expanding universe makes it physically impossible to revisit past configurations of objects, complicating the notion of time travel.
  • There is a disagreement regarding the usefulness of a four-dimensional spacetime view versus an intuitive understanding of time when discussing backward time travel.

Areas of Agreement / Disagreement

Participants generally do not reach consensus on the feasibility of backward time travel, with multiple competing views remaining on the topic.

Contextual Notes

Some arguments depend on interpretations of quantum mechanics and general relativity, and there are unresolved questions about the nature of time and nonlocal interactions in quantum experiments.

  • #121
I'm not too sure the question really was ever answered. To put it fairly simple, we don't really know. The idea of why it is believed to violate special relativity is that entanglement means that objects that are interacting will react at the same time when something happens to one of the objects no matter how far away the two objects are. But this would mean that some sort of signal would have to be interacting with both objects and would be moving faster than the speed of light. This is where the paradox comes from, if the reaction happens instantly than the signal is moving faster than the speed of light and violated special relativity, unless the signal moves backwards through time.
 
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