Indivisible units of time and the quantum eraser experiment

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Discussion Overview

The discussion centers around the concept of indivisible units of time, particularly in relation to the Quantum Eraser Experiment and the implications of retro-causality. Participants explore theoretical ideas about time at quantum scales and how these might relate to observed phenomena in quantum mechanics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that retro-causality in the Quantum Eraser Experiment could be understood as a process occurring along an indivisible unit of time, such as Planck time.
  • Others argue against the existence of indivisible units of time, stating that time behaves consistently across micro and macro scales and is affected by factors like velocity and gravity.
  • A participant questions how light could be divided into smaller segments over a Planck length, suggesting that high-energy photons could have many wave cycles within that distance.
  • There is a suggestion to calculate the energy of high-energy gamma photons to compare it with other phenomena, indicating an interest in exploring the implications of energy scales in this context.

Areas of Agreement / Disagreement

Participants generally disagree on the concept of indivisible units of time and the implications of retro-causality, with multiple competing views presented. The discussion remains unresolved regarding the nature of time and its relation to quantum mechanics.

Contextual Notes

Limitations include the lack of consensus on the definition of time at quantum scales, the assumptions about the nature of retro-causality, and the unresolved mathematical implications of dividing light over Planck lengths.

Gaz1982
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If we take an indivisible unit of time (a Planck time perhaps), could the possible retro-causality hinted at in the Quantum Eraser Experiment be a process where the retro-causality goes back along the same plank unit rather than back in time per se

Metaphor - I don't travel to a different train carriage, just the back of the same carriage.
 
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There is no indications of indivisible units of time. Time is the same on micro scales as it is in macro scales, it doesn't even have the same rate for different velocities or locations in a gravity well, meaning one second for one location could be two seconds for a different location but the physics remains the same locally. The quantum eraser experiments have been done with not nearly enough time for a delayed choice to affect what occurred at a fork "a long time ago" by photon propagation time scales.

In a train analogy, what happens is when the engine at the front of the train has a choice to go left or right and someone at the back of the train says "I don't know which way we are going". As soon as the engineer determines which track to take, the person at the back of the train "instantly" knows a choice has been made, long before any information could reach them.
 
jerromyjon said:
There is no indications of indivisible units of time. Time is the same on micro scales as it is in macro scales, it doesn't even have the same rate for different velocities or locations in a gravity well, meaning one second for one location could be two seconds for a different location but the physics remains the same locally. The quantum eraser experiments have been done with not nearly enough time for a delayed choice to affect what occurred at a fork "a long time ago" by photon propagation time scales.

In a train analogy, what happens is when the engine at the front of the train has a choice to go left or right and someone at the back of the train says "I don't know which way we are going". As soon as the engineer determines which track to take, the person at the back of the train "instantly" knows a choice has been made, long before any information could reach them.
How could we divide light traveling a Planck length in a vacuum?
 
Gaz1982 said:
How could we divide light traveling a Planck length in a vacuum?
Into as many "slices" of time that makes sense. If it were a very high energy gamma photon, it could have 1000's of waves in that distance.
 
Gaz1982 said:
If we take an indivisible unit of time (a Planck time perhaps), could the possible retro-causality hinted at in the Quantum Eraser Experiment be a process where the retro-causality goes back along the same plank unit rather than back in time per se
There's no particular reason to think that the Planck time is indivisible... but even if it were, how does it compare with the time differences involved in the delayed choice experiment?

jerromyjon said:
If it were a very high energy gamma photon, it could have 1000's of waves in that distance.
It would be a good exercise to calculate the energy of such a photon, see how it compares against the energy of various other interesting phenomena.
 
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