sci.physics.research

Phillip Helbig---remove CLOTHES to reply wrote on Sat, 09 Feb 2008
16:37:17 +0000:

> In article
> <779ff48f-57ab-490b-a42d-c426e6a6562b@>,
> "Juan R." writes:
>
>> Neither that work nor Igor have proven such one thing. I have submitted
>> some comments about gravitation at the molecular level in the relevant
>> thread. If it is approved then you can read how Penrose and others
>> claim
>> just the contrary: gravity is fundamental at the molecular level.
>
> I think you will find that Penrose claims that gravity has something to
> do with why macroscopic mixed states are not observed.

One of his thoughts is that gravity modifies quantum theory at the
Planck scale and this is the cause of failure to quantize General
Relativity.

About "macroscopic mixed states" I think you mean observation of quantum
coherence (. Schrödinger cat). But then you are using a misleading
term.

We do not observe are macroscopic pure states. The cat is in some
macroscopic mixed state. Thus he does not follow a Schrödinger equation.

> His opinion is
> not shared by the majority of physics, but I think it's safe to say that
> this area (and others with which Penrose is concerned) is still unclear,
> even to conventional physicists. (In other words, even if people don't
> agree on the solution, most agree there is a problem.)

Penrose is not continuing current paradigm but proposing one new. A look
to the history of physics reveals revolutions (since Newton) were
initially rejected by the _majority_ (the old-paradigm comunity in Kuhn
sense).

Planck famous quote may be relevant:

{BLOCKQUOTE
A new scientific truth does not triumph by convincing its opponents and
making them see the light, but rather because its opponents eventually
die, and a new generation grows up that is familiar with it.
}

> However, IIRC
> the mass at which gravity influences QM was 10^{-5} gram or something
> like that---tiny by our standards, but way above the "molecular level".

They claim gravity modifies QM at Planck scale and next compute
different decoherence times T for different massive objects using
Penrose model.

T for single electrons is of order 10^19 years in that model. Therefore
single electrons will be very well described using QM during all your
life. However, T for a cat [#] is so short like 10^{-37} seconds.

{BLOCKQUOTE [1] The Penrose-Hameroff proposal suggests that coherent
superpositions of tubulin proteins are inherently unstable and subject
to self-collapse under a quantum gravitational criterion Penrose
objective reduction or OR