Comparing Information Loss: Time Dilation vs. Decoherence

[asklepian]

TL;DR Summary

How do time dilation and decoherence cause apparent information loss? Is perceived information loss in high decoherence environments due to faster information transfer, and how does this compare to time dilation effects?

Hello everyone,

In light of this recent paper, I have some questions. I'm trying to deepen my understanding of information loss in the contexts of time dilation and quantum decoherence and would appreciate some insights grounded in established physics theories.

Time Dilation and Information Loss:​

In the case of time dilation, particularly near a black hole, a distant observer sees a clock slowing down as it approaches the event horizon. The clock's ticks (emissions of photons) appear to become less frequent until they cease altogether at the event horizon. This leads to an apparent loss of information about the clock's state for the distant observer.

Decoherence and Information Transfer:​

In quantum mechanics, decoherence describes how a quantum system loses its coherent superposition states due to interactions with its environment. In a high decoherence environment, this process happens rapidly, causing the system to appear more classical and less quantum. The information about the quantum state is transferred to the environment, making it inaccessible to local measurements of the system alone.

Key Questions:​

1. Apparent Information Loss in Decoherence:
   • Is it scientifically accurate to consider the apparent information loss in a high decoherence environment as an increase in the rate of information transfer to the environment?
   • How does this rapid transfer of information lead to an apparent loss of information for an outside observer, who is part of that environment but cannot access the detailed environmental states?
2. Comparison to Time Dilation:
   • Given that both phenomena involve the observer's inability to access complete information, can we draw a meaningful analogy between the information loss due to time dilation and the rapid information transfer in decoherence?
   • How do established theories in quantum mechanics and general relativity explain these apparent losses of information, and what are the key differences and similarities?

I'm looking for explanations that adhere to well-established scientific principles and avoid speculative theories. Your insights and references to relevant literature would be greatly appreciated!

Thanks in advance for your help!
Asklepian

 

[PeterDonis]

In the case of time dilation, particularly near a black hole, a distant observer sees a clock slowing down as it approaches the event horizon. The clock's ticks (emissions of photons) appear to become less frequent until they cease altogether at the event horizon. This leads to an apparent loss of information about the clock's state for the distant observer.

No, there is no loss of information due to time dilation. The distant observer takes longer to see the clock's ticks, but each tick that takes place above the horizon is still seen.

In quantum mechanics, decoherence describes how a quantum system loses its coherent superposition states due to interactions with its environment. In a high decoherence environment, this process happens rapidly, causing the system to appear more classical and less quantum. The information about the quantum state is transferred to the environment, making it inaccessible to local measurements of the system alone.

That doesn't mean the information is lost. Decoherence is a unitary process, and unitary processes do not create or destroy information.

Your questions are unanswerable as they are based on false premises.

 

[asklepian]

No, there is no loss of information due to time dilation. The distant observer takes longer to see the clock's ticks, but each tick that takes place above the horizon is still seen.


That doesn't mean the information is lost. Decoherence is a unitary process, and unitary processes do not create or destroy information.

Your questions are unanswerable as they are based on false premises.

Thank you for your response. I appreciate the clarifications regarding information preservation in both time dilation and decoherence. Here are some points to further the discussion and restate my questions:

Time Dilation:
You mentioned that there is no loss of information due to time dilation because each tick is eventually seen, albeit delayed. I understand that the information is not lost but becomes increasingly redshifted and faint. My question is more about the practical implications for an observer:

How does this delay and redshifting impact the observer’s ability to interpret or utilize the information from the clock as it approaches the event horizon?

Decoherence:
You correctly pointed out that decoherence is a unitary process, and thus information is not lost but transferred to the environment. However, my concern lies in the practical accessibility of this information:

How does the rapid transfer of information to the environment in high decoherence settings affect the observer's ability to retrieve or measure the original quantum state, given the complexity of the environment?

Comparison:
Regarding the comparison between the two phenomena, I was trying to draw an analogy based on the observer’s experience:

Can we consider the observer’s inability to access detailed information in both scenarios as an analogous process, even if the underlying mechanics differ?
How do established theories in quantum mechanics and general relativity address these observational limitations, and what are the key differences and similarities in the way information becomes less accessible to the observer in each context?
I’m looking for insights that adhere to well-established scientific principles and avoid speculative theories. Any further elaboration or references to relevant literature would be greatly appreciated.

Thanks again for your help!

 

[PeterDonis]

How does this delay and redshifting impact the observer’s ability to interpret or utilize the information from the clock as it approaches the event horizon?

In principle it doesn't. The information is there. In practice, any actual detector will not be able to detect signals that are redshifted beyond a certain wavelength, but that is just a practical limitation, not a theoretical one.

my concern lies in the practical accessibility of this information

The whole point of decoherence is that the information is not practically accessible, so the process is in practical terms irreversible. But again, that is just a practical limitation, not a theoretical one.

Can we consider the observer’s inability to access detailed information in both scenarios as an analogous process

Only in the very basic sense that there are practical limitations on our ability to recover information in both cases.

How do established theories in quantum mechanics and general relativity address these observational limitations

What would you expect them to address? As above, these limitations are only practical, not theoretical. In the theoretical models all of the information is still there.

 

[PeterDonis]

I’m looking for insights that adhere to well-established scientific principles and avoid speculative theories.

You don't need to keep belaboring this. The PF rules already require this anyway.

 

[Morbert]

Not quite sure what you are asking OP but you might find these papers relevant

https://arxiv.org/abs/2205.06279v2
https://arxiv.org/abs/2301.00026

They pertain to killing horizons and quantum superpositions