Finding Comfort in the Unity of Life: Coping with Unpleasant Events

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Discussion Overview

The discussion centers around the concept of unitarity in the context of quantum mechanics and its implications for understanding existence and information loss, particularly when coping with unpleasant events. Participants explore theoretical perspectives on unitarity, antiunitarity, and the nature of information in quantum theories.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that unitarity, as defined in standard quantum mechanics and quantum field theory (QFT), implies reversibility and that no information is lost.
  • Others challenge the notion of unitarity, suggesting that existence may not operate under this principle at a human perceptual level.
  • One participant introduces the idea of antiunitary transformations in QFT, questioning the exclusivity of unitarity and suggesting that time reversal transformations are generated by antiunitary operators.
  • There is a viewpoint that while unitarity is often a useful assumption, it may not hold universally, and the uncertainty in theories suggests that fixed unitarity is not necessarily true in general cases.
  • Another participant expresses that non-unitary behavior could be essential to understanding the evolution of theories, proposing that it might play a key role in the conceptual framework.
  • Concerns are raised about the implications of non-unitary information, with some suggesting that as long as its significance is small, it may not pose a problem.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of unitarity and its implications. Multiple competing views are presented regarding the validity and applicability of unitarity in different contexts.

Contextual Notes

Some discussions include assumptions about the nature of existence and the applicability of quantum theories, which remain unresolved. The relationship between unitarity and non-unitary behavior is also a point of contention.

Is the idea "It's all unitary anyway" ever comforting to you?

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When unpleasant things happen, do you ever comfort yourself by saying "It's all unitary anyway..."
 
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> "It's all unitary anyway..."

Is it? :)

/Fredrik
 
Fra said:
Is it? :)

Well, according to standard quantum mechanics it is, also QFT. Unitarity implies reversibility (unitary transformations are invertible), and also that no information is ever "lost".

There is perhaps some doubt about whether quantum gravity is unitary, last I heard though Hawking had joined the "no information loss" camp.
 
No. Existence may be a zero-sum game at some level, but we as humans do not exist/perceive at that level.
 
Fra said:
> "It's all unitary anyway..."

Is it? :)

/Fredrik

Is except it?

Thanks.
Mr Beh
 
Last edited:
Why not antiunitary? :smile:

Well, according to standard quantum mechanics it is, also QFT. Unitarity implies reversibility

In QFT, time reversal transformation is generated by the antiunitary operator;

[tex]\mathcal{T} \phi (x,t) \mathcal{T}^{-1} = \eta_{T} \phi (x,-t)[/tex]

(unitary transformations are invertible)

So is any non-singular transformation!

and also that no information is ever "lost".

All depends on the vacuum; whether it is true or fulse vacuum!:confused:


sam
 
Proof.Beh said:
Is except it?

Thanks.
Mr Beh

The way I see it, unitarity is more often than not, the best single guess, but it's not the only option. There mere uncertainty alone implies that to think that there is a fixed unitarity can hardly be true in the general case. But of course in many special cases.

It's not a coincidence though that theories almost be definition, apply to "special cases".

In my thinking I don't think of special theories, I think of something as close to the general case my small mind can grasp, and I can't accept unitarity as a fundamental thing. Technically, it would IMO be exepctations. But since these expectations are often well supported, they appear to be alost fundamental. But the different in the viewpoints is on the edge of the theories evolution. I have at least, hard to understand a fundamentally evolutionary model without non-unitary behaviour. In my thinking the non-unitary behaviour is even part of the key.

/Fredrik
 
As long as the non-unitary information part is small in relative significance, it's not a problem IMO. But the non-unitary isn't fundamental either of course. Typically the implication of learning is a desired to inflate the models to make it more unitary.

/Fredrik
 

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