Re: Lorentz Ether Theory and FTL Paradoxes

From: Bill Hobba (bhobba_at_rubbish.net.au)
Date: 09/08/04 

Date: Wed, 08 Sep 2004 22:18:30 GMT

"chaverondier" <bernard.chaverondier@wanadoo.fr> wrote in message
news:a883a4e1.0409072309.29a4037d@posting.google.com...
> "Bill Hobba" <bhobba@rubbish.net.au> wrote in message
news:<0oq%c.22966$D7.12175@news-server.bigpond.net.au>...
>
> Bill Hobba
> > > > In QM one interpretation of Bells inequality is that 'objective
reality'
> > > > exists (sometimes called 'realism') but influences propagate faster
> > > > than light (in fact instantaneously) which is summed up by saying
> > > > reality is non local. However the effect can not be used to send
> > > > information by us - at least no one has figured out how.
>
> Chaverondier
> > > One can even prove such a faster than light transfer of information
> > > thanks to EPR effect to be impossible provided we assume
> > > quantum measurement indeterminacy to be fundamental
> > > (see for instance the no_communication theorem,
> > > in "Quantum information and relativity theory",
> > > Reviews of modern physics, volume 76, January 2004.
> > > Asher Perez, Department of physics,
> > > Technion-Israel Institute of technology,
> > > 32000 Haifa, Israel and Daniel R. Terno
> > > Perimeter Institute for Theoretical Physics,
> > > Waterloo, Ontario, Canada N2J 2W9).
>
> Bill Hobba
> > Wrong - if one denies 'realism' then one of the assumptions that proves
> > non local influences goes out the door ie the assumption of the
existence
> > of hidden variables.
>
> Chaverondier
> So what is wrong ? That's exactly what I said. If you assume a
> fundamental indeterminism, then, there is no contextual hidden
> variables and so no possibility of faster than light communication
> thanks to EPR effect.

Now I know what you mena by funamntal indeterminism.

>
> Chaverondier
> > > On the contrary, in the case when we assume quantum indeterminacy
> > > and Von Neuman chain break (as well as measurement induced entropy
> > > increase) to stem from an observer connected information
incompleteness...
>
> Bill Hobba
> > Those are lot of assumptions to make. The problem with the Von Neumann
> > chain break is that we can assume with perfect logical consistency that
the
> > observation induced changes in a quantum state can occur in the
> > consciousness of the observer.
>
> Chaverondier
> In my opinion, there is no serious reason to assume such an
> hypothesis.

I agree. But can I dismiss it - no. OTOH do interpretations exist where it
is not a problem - yes. To me this indicates the whole discussion is rather
pointless.

>
> To provide a classical _analogy_, there is no reason to assume that a
> classical observer creates the entropy increase of a macroscopic
> system encompassing a lot of classical particles. You have only to
> drop the information about correlations between the positions and
> momenta between particles to model this observer related entropy
> increase. This loss of information is not a fundamental loss but is
> observer related one (the macroscopic observer cannot have an easy
> access to these microscopic correlations).
>
> This observer related impossibility is modelled by the probability
> distribution of particles in the one-particle phase space (the so said
> 6 dimensional micro-space) and gives rise to an entropy increase when
> the system evolves. On the contrary, if the system of N particles is
> completely modelled, without dropping any information, you have to
> consider the Gamma-space (the 6^N dimensional phase space). In such a
> space, even if you have only an imperfect knowledge (so that you have
> a distribution of probabilities in this huge space), the probability
> density is conserved thanks to the Langevin equation and the Gibbs
> entropy can be proved to be _constant_ (see "The Direction of Time"
> (Hans Dieter Zeh) http://www.time-direction.de/ , chapter 3 the
> thermodynamic arrow of time). In the gamma-space, there is no loss of
> information, no entropy increase, no irreversibility and no
> indeterminism.
>
> On the contrary, entropy increase, indeterminism and irreversibility
> show up in the micro-space. They exhibit an increasing loss of
> information of the observer in the incomplete model provided by a
> probability distribution in the micro-space because this model ignores
> the correlations between particles momenta and positions (be careful,
> its only an analogy. There is no mean to measure simultaneously
> momentum and position of quantum particles because of Heisenberg
> incertainties of course).
>
> Now, let us come back to _quantum_ statistical mechanics. If you don't
> break arbitrarily

It does not need to be broken arbitrarily at all. I linked to
interpretations where it is not even an issue -
http://quantum.phys.cmu.edu/histories.html. That is the trouble with all of
this stuff - it is pie in the sky based on specific interpretations for
their to even be an issue in the first place.

> the Von Neuman chain, never any indeterminism,
> irreversibility and entropy increase show up. The evolution stays
> inalterably, unitary, determinist and reversible.
>
> So, when does quantum measurement indeterminism, irreversibility show
> up ?
>
> The answer is : when the observer uses the _reduced_ density operator
> of an open system (and, in quantum mechanics, all quantum systems
> become open ones sooner or later). That's to say when the observer
> decides to drop the information about the EPR correlation of the
> observed system with its environment (he is contrived to do so because
> he has no easy access and no control over these correlations). You get
> an entropy increase when you let the Von Neuman Chain grow out of your
> observed system that's to say if you model only the _reduced_ density
> operator of the observed system.
>
> When you do that (and you are contrived to do that as a real observer)
> you drop a part of the information that models the non local
> interaction of your system with its environment. Your system is said
> in a "mixed state" which means that the density operator is not any
> more a projector of rank 1. He becomes a weighted sum of projectors of
> rank 1, which means that you don't know any more the exact state of
> your system.
>
> Indeed, in Quantum mechanics, the parts cannot be modelled exactly
> (that's to say accounting only for local action) knowing the quantum
> model of the whole.
>
> Here is actually (in my opinion) the quantum measurement
> indeterminism, and it is not a fundamental one. It is an observer (and
> quantum non-locality) related indeterminism.
>
> Bill Hobba
> > we even have interpretations where the break does not even occur.
>
> Chaverondier
> That's also my interpretation. Of course, their is no need (in my
> opinion) to assume the Everett many worlds
> Rather, ainterpretation.

That is not the interpretation I linked to.

> more prosaic interpretation resting on the inability of the observer
> to "run behind the swiftly growing Von Neumann Chain" is enough.
> Whatever his care, there is always a moment (and it happens very fast
> because EPR intrication doesn't respect the light speed limit) when
> the Von Neumann EPR intrication chain grows out of the observation
> area.
>
> Bill Hobba
> > People who harp on this issue deliberately ignore the second alternative
> > - see the following for an example of an interrelation that avoids this
issue -
> > http://quantum.phys.cmu.edu/histories.html. It is not the only one
either.
>
> Chaverondier
> Thank you for the link. I will have a look. You provide valuable links
> (I knew of quantum state diffusion theory thanks to a link you
> provided on spr about this topic).

Thanks for taking the time. The more people understand that interpretations
of QM exist that get around its so called problems the more reasoned debate
we can have.

Thanks
Bill

>
> Chaverondier
> > > If we assume quantum indeterminism to stem from the observer
> > > related break of the Von Neumann chain, then there is (at least from a
> > > principle point of view) a mean to send a correlation signal faster
than
> > > light using EPR effect.
>
> see http://perso.wanadoo.fr/lebigbang/epr.htm
> and http://perso.wanadoo.fr/lebigbang/no_communication.htm
> for more details
>
> Bill Hobba
> > Then carry out the experiment and have it confirmed.
>
> Chaverondier
> Of course that's a good objective. As you can guess it is a long and
> difficult research program because it needs first to model with care
> the dynamics of quantum measurement (in the direction Professor GISIN
> and Ian Parcival began to do in their quantum state diffusion theory).
> When this task (which probably needs a lot of years) is enough
> advanced, then and only then is it possible to begin to work on the
> research program of a real experiment devoted to test quantum
> determinism hypothesis and after that on a real test of the
> possibility to send a self-correlation signal faster than light thanks
> to EPR effect (provided the theoretical research about quantum
> measurement has not proved that to be impossible because of problems
> with the order of magnitude of time scales and distance scales to
> handle or because of technological impossibilities for instance).
>
> Of course, one can consider such a research program to be interesting
> only when it is enough advanced to be taken seriously. It is a matter
> of opinion.
>
> Bernard Chaverondier

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