Questions about black holes and the Hawking radiation.

[Carrock]

From https://www.nature.com/articles/s41467-019-08426-4

30 minutes ago, beecee said:

Here we consider the decoherence of a “black hole Schrödinger cat”—a non-local superposition of a Schwarzschild black hole in two distinct locations—due to its Hawking radiation. The resulting decoherence rate turns out to be given by a surprisingly simple equation. Moreover, and in contrast to known cases of decoherence, this rate does not involve Planck’s constant ħ.

Another quote from that paper:

Quote

They also present the decoherence by Hawking radiation as something fundamental and unavoidable, just as we do.

 

Ouch. From a reference from that paper:

Joos, E. et al. Decoherence and the Appearance of a Classical World in Quantum Theory. (Springer, Berlin Heidelberg, 2003).

 

Quote

Decoherence is caused by the information flowing from the system into its environment and the resulting formation of records of its selected observables in that environment

So a whole paper with quantified maths about an arbitrary split between quantum superposition and a purely classical environment i.e. no superposition of different 'records.'

This would only be valid if the Copenhagen interpretation was a distinct theory rather than an interpretation.

Dubious theory isn't confined to SF speculation section...

 

 

[Carrock]

I suppose on second thoughts that paper is a pretty normal Copenhagen interpretation; it's just the scale of the superposition that's unusual.

[MigL]

You fail to realize that these are interpretations.
In that particular paragraph he actually uses two interpretations of the mechanism for reducing the EH.
One involves particles of negative energy moving forward in time and also positive particles moving backwards in time.

The theory/model is mathematical ( which you seem to abhor ); the 'interpretation' is a comparison to easily understood concepts.
I'm sure you are familiar with the Copenhagen and Many Worlds interpretation ( and others ) of Quantum Mechanics.
Does it mean that if your cat isn't alive AND dead in a box simultaneously, the theory/model is wrong ???

Why didn't you read further in that paragraph where S Hawking states...

"It should be emphasized that these pictures of the mechanism responsible for the thermal emission and area decrease are heuristic only and should not be taken too literally."

It's obvious we will never convince you, but we are presenting the accepted science.
You are more than welcome to post ( and support ) your conjectures in Speculations.
Good luck with that.

[beecee]

1 hour ago, MigL said:

It's obvious we will never convince you, but we are presenting the accepted science.
You are more than welcome to post ( and support ) your conjectures in Speculations.
Good luck with that.

Eloquently put!

[Carrock]

21 hours ago, Carrock said:

I suppose on second thoughts that paper is a pretty normal Copenhagen interpretation; it's just the scale of the superposition that's unusual.

I realised I'd got it wrong, too late to edit my OP; I didn't make that clear enough.

Or that I had realised

Quote

Decoherence is caused by the information flowing from the system into its environment and the resulting formation of records of its selected observables in that environment

is consistent with any valid QM interpretation. (The referenced book is behind a paywall; how 'environment' is defined is of course crucial.)

 

Clarification:

 

7 hours ago, MigL said:

You fail to realize that these are interpretations.
In that particular paragraph .....

You appear to be referencing an unspecified paragraph from "Hawking, S. W. Particle creation by black holes. Commun. Math. Phys. 43, 199–220 (1975)."

As I didn't quote from it, I don't think a cited reference has much relevance to the quality of the citing article.

8 hours ago, MigL said:

The theory/model is mathematical ( which you seem to abhor );

Don't know where you got that from...

7 hours ago, beecee said:

Eloquently put!

Congratulations on the cheerleading. +1

 

In summary: nothing in the paper appears to depend on a particular interpretation. I originally thought it did.

[MigL]

Sorry Carrock, although your posts 'inspired' my response, it was actually meant for Q-reeus, who is no longer with us.
I apologize for the confusion my lack of specifics caused.

[Carrock]

2 hours ago, MigL said:

Sorry Carrock, although your posts 'inspired' my response, it was actually meant for Q-reeus, who is no longer with us.
I apologize for the confusion my lack of specifics caused.

Yours was a good response to my rubbish post.

I misinterpreted the paper, the red mist descended and I pressed 'Submit Reply' without engaging brain...

[beecee]

The general message as I previously mentioned before, is that Hawking Radiation appears to most reputable mainstream scientists, as a viable process that seems likely, albeit described by different methodologies. Analogous experiments as previously detailed also support the reasonable concept of Hawking Radiation.

Here's another interesting take and experiment.......

https://medium.com/the-physics-arxiv-blog/first-observation-of-hawking-radiation-9d77fa8c8055

"In 1974, the British physicist Stephen Hawking made a remarkable prediction about black holes. Hawking said these objects, which are so dense that light cannot escape from them, must emit radiation.

That was a huge surprise. What kind of radiation could this be? Clearly it could not be produced inside the black hole so where would the emitted particles come from?

After much scepticism and intense debate, physicists eventually accepted the idea that black holes probably do emit “Hawking radiation” as it become known. But although astronomers have discovered many black holes since then, nobody has spotted the tell-tale radiation that Hawking says they must emit.

Now a group of Canadian physicists say they’ve measured Hawking radiation for the first time, but not from a black hole. Instead these guys have created a “white hole” in their laboratory, the time reversed equivalent of a black hole, and measured the radiation it produces.

But is this really Hawking radiation? Today, one of them, Bill Unruh from the University of British Columbia in Vancouver, argues that because of the formal mathematical equivalence between white holes and black holes, the answer is yes: they really have seen Hawking radiation for the first time."

more at link......

the paper:

https://arxiv.org/pdf/1401.6612.pdf

Has Hawking radiation been measured?

It is argued that Hawking radiation has indeed been measured and shown to posses a thermal spectrum, as predicted. This contention is based on three separate legs. The first is that the essential physics of the Hawking process for black holes can be modelled in other physical systems. The second is the white hole horizons are the time inverse of black hole horizons, and thus the physics of both is the same. The third is that the quantum emission, which is the Hawking process, is completely determined by measurements of the classical parameters of a linear physical system. The experiment conducted in 2010 fulfils all of these requirements, and is thus a true measurement of Hawking radiation.

Edited April 19, 2019 by beecee