Subject: Re: faster than light travel
From: Anthony Potts
Date: Thu, 12 Dec 1996 16:42:02 GMT
On Thu, 12 Dec 1996, Anthonie Muller wrote:
> I have even seen a demonstration on the BBC TV (Horizon) on monday Dec 2.
>
> It concerns Guenther Nimtz, at the U of Cologne. He demonstrated
> on a scope how a microwave signal tunnelled through a barrier at a
> speed faster than light. He used a signal that contained music from
> Mozart.
>
You are confusing two different experiments here, just as the person
carrying out the experiment did. First, he showed that particles quantum
tunneled at greater than the speed of light. Secondly, he showed that
using particles passing through the barrier, you could carry a signal.
He most definitely did not show that the signal thus carried was
travelling faster than the speed of light.
I was quite frankly aghast at the way this experiment was presented. I
don't know whether it was because of the programme makers inability to
comprehend, or because the scientist himself was wrong, but someone
certainly lost the plot.
They just didn't seem to know the difference between group velocity, phase
velocity, and signal velocity.
> - Finally, the main problem is the large number of cranks and
> attention seekers in this field. God only knows why they choose
> relativity, and not quantum mechanics or chess. As a scientist has to
> rise above the noise that these people make. I am now working on a model
> for the origin of life, and this field has the same problem.
> Instead of enjoying science these people only make it, and themselves,
> distastefull for others.
>
> I, of course, can only hope that I am not one.
>
The problem is, the cranks cannot see why they are cranks. They imagine
tat what goes on at university is some strange brainwashing, and that they
actually kow better than the trained scientists.
You have to wonder, though. If these people never made it to university,
how come they reckon that they are so good at science?
Anthony Potts
CERN, Geneva
Subject: Re: Time travel? What about Deja Vu's?
From: Anthonie Muller
Date: Thu, 12 Dec 1996 15:47:45 +0000
On Wed, 4 Dec 1996, I H Spedding wrote:
>
> My own pet theory is that deja-vu is a false-positive identification
> error that is a built-in weakness of our visual system.
>
> When we see something new we look at it closely. In effect, we
> subject it to a sort of high-resolution scan that adds the image to
> our visual 'archive'. However, to do that sort of high-res scan on
> everything we look at would be much too slow and cumbersome a process.
> So, on the first-pass scan of the scene the brain just looks for clues
> or distinguishing characteristics which it tries to match to images in
> the memory. If it finds a match it pulls that image from the memory
> and uses it to do a fill-in-the-blanks on whatever is being looked at.
>
> The problem is that such a system is bound to make the ocasional
> error. I should think most of us have had the experience of seeing
> some one at a distance in the street and thinking to ourselves
> " Hey! That's ******!". Except that when we get up close we see that
> it isn't ****** after all. They just looked similar from a distance.
> Similar enough to cause the brain to pull the wrong picture from the
> files. Remember, though, you *felt* you recognised them, that
> recognition is a feeling.
>
> So maybe the brain does the same thing with sequences of events.
> Maybe, in deja-vu, what happens is that a sequence of events you
> experience hasn't actually occurred before but it is similar enough to
> one that has, to cause the brain to trigger that feeling of
> recognition.
>
> Anyway, that's my idea.
>
> Ian
I have also thought about such an explanation by a fault during
association. However, during deja vue I do not feel that I
recognize something, but I feel that I experience something for a
second time. The first experience (with which the contemporary
experience is compored) is however often vague, and I often
wonder whether this first experience was during a dream or not.
During recognition one is in general sure on whether one (1) has seen it
before, or (2) has not seen it before, or (3) whether one is unsure. Such
a division is not typically made during deja vue. (I do not find this a
strong argument myself, by the way).
I have the impression that deja vue occurs especially upon
relaxation from a state in which one is very busy. Deja vue is also dream
like in this respect that the details of the experience are easily
forgotten.
Another explanation is the following. We all know that some
smells can evoke memories from a long time ago. So some rarely
present chemicals or combination of chemicals made in the body might evoke
the deja vue experience by evoking old memories.
On the other hand - we might be able to look in the future, but there
might be a physical law that permits us to do so only in a
random way.
Of course we know our future already: in a hundred years we
will (almost) certainly be dead, and there will no one be present any
more that cares about us. But we deny this, and hope for something more
in between.
The deja vue experience results in a fertile feeding ground for all kind
of con men: the weeds may be overgrowing the real thing.
I have not read the literature on this subject, and I am often feel
irritated in this newsgroup when people give opinions without having
read a little bit in textbooks or in the library, and now I am one of them
myself - I should stop.
Ton Muller
Subject: Re: Room Temperature Superconducting Powder
From: mblack2@yttrium.helios.nd.edu (M. Black)
Date: Thu, 12 Dec 96 20:48:09 GMT
In article <58pcuj$32a@sjx-ixn8.ix.netcom.com>,
Alan \"Uncle Al\" Schwartz wrote:
>mblack2@yttrium.helios.nd.edu (M. Black) wrote:
>>In article <58na31$osm@sjx-ixn5.ix.netcom.com>,
>> Alan \"Uncle Al\" Schwartz wrote:
>>>"Cris A. Fitch" wrote:
>>>>Hi Folks,
>>>> I heard a news report (CBS Radio) on a French team which
>>>>had announced the production of a powder which would superconduct
<<>>>
>>>Since grain boundaries would render the stuff uselessly lossy, one
>
>>not so fast... the low temp SC are rife with gb (grain boundaries) and
>so are the BSSCO tapes. In fact in low temp SC (Nb_3Sn etc.) the gb and
>dislocations act in such a way as to increase the amount of current the
>sample can carry losslessly.
>
>In order to work as a useful supercon the grain boundaries must be at low
>angles and the solid must be compact. Neither condition is met by a
>powder.
>
The orientation of the gb is only significant in HTc materials because of the
short, anisotropic coherence length. In the low Tc SC the gb orientation is
not a significant problem.
>
>>I did read that the sample contained Li,Be and H, and that the SC
>>was not independently confirmed. Some searching on the web found that one
>>of the authors (Jean-Pierre Bastide) published a paper on LiBeH_3 and
LiBeH_4
>>in 1990. I suspect that these compounds only form under conditions not
>>commonly experienced in most labs, i.e. high pressure and temperature.
>
>
>Formation of such should be trivial Start with BeH2, add two moles of
>LiH in a non-acidic solvent or inert molten salt flux. That will get you
>to Li2BeH4. Mix mole/mole with BeH2 and repeat to get LiBeH3. Consider
> synthetic routes to LiAlH4 given LiH and AlH3 (alane).
>
The paper (J.P. Bastide, Solid State Comm. 74,5, 1990, pg 355-8) is a review
of previously published crystallographic data on lithium beryllium hydrides.
In the paper they state that to their knowledge only three attempts have been
made to make the compounds as of 1990. I was wrong in my suspicions though,
since the reluctance lies in the danger of working with Be compounds and the
high reactivity of hydrides in general towards air and moisture. One study
(Ashby and Prasad, Inorg. Chem. Vol.14, no. 12, 1975, pg 2869-74) formed
LiBeH3 by reacting AlH3 and LiBe(CH3)3 in diethyl ether. The reactions were
carried out in a nitrogen filled glove box or using typical Schlenk-tube
techniques. I would not describe this as trival.
The preperation of your starting materials ,LiH and BeH, might prove the most
difficult step of your scheme since buying them ready made might prove
difficult. For example, Ashby and Prasad prepared LiH by hydrogenolysis of
tert-butyllithium in pentane at 4000psi for 24hrs.
Marc
Subject: Re: Propellant Free Space Drive
From: david8@dax.cc.uakron.edu (David L. Burkhead)
Date: Thu, 12 Dec 1996 02:54:22 GMT
Joe@stellar.demon.co.uk (Joseph Michael) wrote:
:>In article <58k7ln$150@kira.cc.uakron.edu>
:> david8@dax.cc.uakron.edu "David L. Burkhead" writes:
:>Thanks for this long winded spoof.. But what you have said is
:>a mistaken on at least one count and says what I
:>I say but fail to quote the solution included in the same sentence.
:>There are diagrams, and there are references to diagrams,
:>so please read what is ther IN ITS ENTIRETY before wasting
:>so much of your time...
I _did_ read it in its entirety. And, quite frankly, that was the
waste of time. I saw a lot of pretty pictures, a lot of armwaving
verbal arguments (based, in more than one case, on non-physical
assumptions), and not one actual calculation. For one thing, you are
_not_ going to get a "flat," non-varying, field strength in any finite
pulse. Doing that requries harmonics all the way up to infinity. The
shorter the pulse, the higher those frequencies have to go to even
approximate it. Furthermore, atempting to do so requires that one
consider the greater impedence that those higher frequency components
face when hitting that electromagnet.
:>>Okay, let's go over this.
:>Alright!.. :-)
:>>First, the "apparatus" consists of two electromagnets separated by a
:>>non-magnetic material (first, that's a misnomer since all matter is
:>>made up of charged particles and is affected at some level by magnetic
:>>fields--second, as we will see shortly, that's less of a factor than
:>>one would at first assume).
:>In other words, you could have ignored it?
:>Jeez.. what a way to nit pick!
You were the one to make an issue about it being "non magnetic"
as if it were an important feature.
:>>Now, an electromagnet is, at heart, a bunch of nearly closed loops
:>>(generally coils of wire) through which a current can be passed.
:>The first and a most fundamental mistake. In your diary an electromagnet
:>is a bunch of closed loop coils of wire because that is all you imagined
:>them to be. Let me tell you, as you should have known from ALL THE DIAGRAMS
:>which you say you have reviewed twice now, that there is not a single coil
:>there of such a description. What? How? When? Where?
If there isn't a loop of current, whether wire, charged particle
beams, traces of semiconductor material, or little elves passing
charged pith-balls around then you don't have an electromagnet.
That's not a description, that's a _definition_. The important factor
isn't the substance of which it's made or the physical form, but the
current loops. That's why I put the "generally coils of wire" in
parentheses--descriptive information so that people can relate the
physics, current loops, with physical objects they might well have
held in their hands.
:>Well look at it again! http://www.stellar.demon.co.uk/stellar.htm
:>The coils talked about there are single ring multi-segmented photocells.
:>That is not the same as the coil you describe - which will NOT correctly
:>work according this complete wasted analysis you gave and which I
:>happen to know very well thanks...!
A single ring is still a current loop. The only difference is
that you need a higher current with a single loop than with multiple
loops to produce a given field strength.
:>Let me also warn you here, this device is not about
:>the properties of switched coils - it is about the properties
:>of a multi-segmented photocell semiconductor with a step work function
:>fabricated into a ring device and illuminated by ultra fast laser pulses.
So you use an optical switch that includes the current source
function. The only thing you've managed to accomplish, physically, is
to reduce the efficiency of your photon drive still more since neither
laser nor photocell are terribly efficient energy converters.
:>Because of the step work function, the system is non-linear and
:>Maxwell's equations have NO solutions. But, simple assumptions
:>can be made about piecewise linearity and the solutions described
:>in the web page is based around that working assumption.
Gee. I guess my work in chaos and non-linear systems is all
wasted, huh? After all, non-linear systems have no solutions.
Please. They may not have any analytic solutions composed only of
elementary functions, but they still have solutions (although, being
non-linear, they may not have _unique_ solutions, and solutions are
may be complex or may involve non-physical results, but that's another
story). Furthermore, I know of no true "step" functions in any
macroscopic system.
For all of this you may not be able to come up with analytic
solutions (even if one assumes that a step function is a valid
approximation of the actual physical event), but instead have to come
up with a numerical solution, but these days that's not all that hard.
I just recently completed a project to produce a fourth-order accurate
numerical solution to a chaotic solution--generating phase spaces and
Poincare sections. It was an afternoon's work with a commercial math
package (Mathcad, to be precise--not terribly powerful, but I like the
user interface).
:>So you really did waste a lot of time describing all of this following..
:>>The
:>>moving charges form a magnetic field. So far so good. This gives you
:>>a field whose strength and polarity can be controlled by changing the
:>>current in the loops. However, a coil of that nature has another
:>>property--inductance (actually, it's a consequence of that magnetic
:>>field). This means that it resists changes in the current. To
:>>increase the current in the coil you have to spend energy. Energy is
:>>given up in decreasing it. And the faster you try to change that
:>>current, the higher the voltages involved in producing the change.
:>[snip.. wasted remainder deleted]
:>While you are correct in saying this about standard coils, it
:>is completely off the subject as the discussion in a semiconducting
:>photocell has to invoke
:>electron hole pairs, charge separation, work function, carrier lifetime etc.
:>In very brief half lay terms I'll try to explain..
Instead of lay terms why not use actual mathematics and
calculations.
:>Semiconductor photocells illuminated by laser pulse have no rise time
:>as such. When a photon that has exceeded the work function of the material
Myth #1, in several parts. a) not all photons produce electron
hole pairs (as described below). b) photons striking different sites
to produce said pairs travel different distances and therefore are
produced at different times. c) the movement of said elextron/holes
will be affected by other forces once produced--say, the magnetic
field generated by the net current--d) the time when the electron is
release is uncertain itself--on close order to the period of the
driving photon.
Since to produce a significant magnetic field you need a great
many electrons moving in synch, you cannot blindly apply the near
instantaneous nature of the individual quantum event ("near" because
of the quantum uncertainty of exactly when it does happen) to the
entire system. Even if you are able to produce an instantaneous or
near instantaneous rise in voltage (potentially possible) you won't
get a similar increase in current because of the inductance of the
system, which tends to resist changes in current. Reducing inductance
does not help you since, to get the same field strength, you have to
increase the current. The two effects cancel.
:>hits the semiconductor, it releases an electron hole pair to drift in
:>the already present space charge of the PN junction. It does not matter
:>if one pair or a million or a billion pairs are created - there is no
:>concept of a rise time in this quantum world! The charge carriers simply
:>come into existence throughout the material and drift in the space
:>charge of the PN junction. This is a non-linearity and if you tried
:>to apply Maxwell, you will get infinities in dI/dt and dQ/dt terms.
Go study your improper integrals again. Calculus can handle
infinities. Also, once again, even if the individual electron
productions are for all practical purpsose instantaneous, not all the
electrons are produced at the same time. As a result, the voltage
(which is what you're creating, after all) most definitely will have a
rise time. Furthermore, the voltage, even if it were instantaneous,
would not result in an instantaneous rise in current because that
current is affected by the inductance of the system.
:>The carriers have a lifetime before the electron hole pairs re-combine.
:>There is a constant using up of the electron hole pairs such that
:>with a given lifetime, if the light source is removed, then most of the pairs
:>will eventually anhiliate and settle back down to the normal background
:>state. When the light source is removed, this anhiliation process
:>can remove charge at a very high rate throughout the semiconducting
:>material as the whole material turns insulator. Once again Maxwell
:>breaks down as dQ/dt and dI/dt are not commensurate with normal
:>conducting material properties.
It's not Maxwell that's breaking down, it's the model you're
using to apply it. Maxwell doesn't _care_ about what the material is.
It only cares about charges, movements, and fields. While it may
break down in quantum events (in fact, it does) you then have to apply
the relevant quantum approaches. So, if you're claiming Maxwell
breaks down here, have you applied QED to it?
:>Most semiconductors and non-linear materials are similarly weak
:>in the application of Maxwell's 'laws' under many conditions.
:>Magnetic pulses created routinely in lab experiments are 4-12 picosecond
:>for GaAs without the usual concept of a rise time. So you see, I'm
Source please? Also, how strong are these fields? And I doubt
you'll find any definitive "0 rise time" claims--"too small to measure
with available instruments" is the most I'd expect any reliable
researcher to claim.
:>not calling for something that is unknown.. Simply - for somebody in NASA
:>or someone with a GaAs photocell facility to test this theory before
:>spending billions reaching for Mars on propellant only rockets.
:>At most it would cost someone a few hundred dollars if they have the
:>facilities already and $50,000 if they don't.
Instead of trying NASA, why not try Boeing or LockMart or MacDAC?
After all, if your idea really worked they could make a _bundle_ at
it. I'm quite sure they have physicists working for them capable of
understanding your theory. If it were to work as you claim it would
make the company that got in on the ground floor embarassingly
wealthy. And even if the big companies were so caught up in "NIH"
that they couldn't do it, then why not try the entrepreneurial route.
Even if it doesn't work, you would always apply the "Barnum 60 Second
Principle."
Bluntly though, I'm highly distrustful of any claims of physics,
particularly those that promise the moon (or, in this case, Mars),
that are made in words rather than equations and calculations. As
Henry Spencer used to have in his sig: "Belief is no substitute for
arithmatic."
David L. Burkhead "If I had eight hours to cut down
david8@dax.cc.uakron.edu a tree, I'd spend seven sharpening
FAX: 330-253-4490 my axe." Attributed to Abraham
SpaceCub Lincoln
http://GoZips.uakron.edu/~david8
Subject: Re: Should a theory explain why?
From: nurban@csugrad.cs.vt.edu (Nathan M. Urban)
Date: 12 Dec 1996 18:59:39 -0500
In article <58nnrv$hh4@pulp.ucs.ualberta.ca>, wetboy wrote:
> : >> Nathan M. Urban wrote:
> : >> one of the foundations of the
> : >> scientific method is a quest to understand "why" things are the way
> : >> they are. By "why" I mean a clear understanding of the cause for
> : >> what we observe.
> It's nice when a theory explains all of the good things one
> learns in first year journalism: who, what, where, when, why,
> how, and so what; but, in my view, the only requirement of
> a good scientific theory is that it make specific,
> quantifiable, valid, and unambiguous predictions.
For the record, I was not the author of the quote you attributed to me.
I agree with your view.
[sci.physics.research removed from Newsgroups: line.]
--
Nathan Urban | nurban@vt.edu | Undergrad {CS,Physics,Math} | Virginia Tech
Subject: Vietmath War: coconuts
From: Archimedes.Plutonium@dartmouth.edu (Archimedes Plutonium)
Date: 12 Dec 1996 22:03:51 GMT
Where there coconut trees in Vietnam? I once lived in Malaysia and do
not remember coconuts but a lot of different fruits.
Started Wednesday, 11Dec by buying a coconut at the local COOP
foodstore, I just had a craving for fresh coconut. And paid $1.19 and
went to the Inn to use a cleaver on cracking it open. Sure enough it
was rotten inside. Went back to the COOP and exchanged it for free for
another coconut and bicycled back to the Inn cracked it open sure
enough this second one was rotten. I have had a horrible count of
rotten coconuts. Ended up exchanging it for a Bahlsen Grandessa cookies
chocolate covered ginger bread with a paper-egg-white bottoms. These
cookies are great but my coconut craving did not go away. I firmly
believe that a craving is the body telling you that some special
chemicals are in fresh coconut that the body needs badly. It could be a
molecule or even atoms of scarce elements.
Biology question, are coconuts more susceptible to some bacteria or
fungi or whatever? Or is it that coconuts may sit in stores for a long
time and prone to go rotten? Any coconut experts out there.
Chemistry question, do coconuts have any scarce chemicals, or
elements contained within?
Math question, what p or n adics describe the spherical shape of
coconuts the best?
Physics question: And also, just today while opening a package of
Ricola cherry cough drops and I wanted to empty the contents out into
my coat pocket so I ripped a nice big hole in the paper package, a hole
bigger than any of the drops inside and I lifted the package
perpendicular. Now, in math where noone gets out much to experiment
with the real world, these math people would immediately assume that
the contents of drops would spill out of the sack because the hole is
larger than any of the drops inside. But that is false for none came
out of the sack, they were all clustered around the opening that each
prevented the other from exiting. The reason I bring this up is that in
mathematics, especially a proof, there are so many assumptions that
almost everyone agrees they are true without a second thought. And it
would be easy in math proof to come to a point of the argument where
you say that a sieve or hole is bigger than any of the elements and
hence the elements trickle out or through. The point I am making is
that many math proofs have flawed hideous assumptions. For example, the
Wiles alleged FLT assumes that Naturals are not the p-adics and then
blithely uses p-adics. The above true story about the Ricola, and I am
always watching for these things, importance is that we assume so many
things in our arguments whether mathematics or daily living.
But I would like to know if coconuts are more susceptible to
rotteness than other fruits?
Subject: Re: Are there any phenomena that Quantum Theory fails to explain?
From: erg@panix.com (Edward Green)
Date: 12 Dec 1996 19:40:54 -0500
John Sidles wrote:
>Michael Ramsey <74553.2603@compuserve.com> wrote:
>>
>>There are problems with QM. Nobody can explain very well what causes
>>the Schrodinger wave equation to collapse. There is nothing in the
>>mathematics to motivate the jumping between stationary states. That is,
>>QM has a problem explaining why the real world is particulate. Clearly,
>>the math is either not the whole picture, or it is incomplete.
>
>Not the case! This issue is addressed in a preprint recently
>posted to "http://xxx.lanl.gov", preprint no. quant-ph9612001,
>entitled "The AC Stark, Stern-Gerlach, and Quantum Zeno Effects in
>Interferometric Qubit Readout".
>
> For the benefit of students new to quantum mechanics, we
> remark that introductory textbooks often contain simplified
> or axiomatic descriptions of measurement processes which
> sometimes lend an unnecessarily paradoxical aspect to
> well-understood phenomena like the Stern-Gerlach effect.
> The results presented in this article are in accord with an
> increasingly dominant modern view\,---\,but a view
> requiring substantially more complicated calculations than
> are typically included in introductory texts\,---\,in which
> measurement processes work gently and incrementally to
> create correlations between macroscopic variables (like
> photodiode charge~$q$) and microscopic variables (like
> qubit polarization~$z$). At the end of an interferometric
> qubit measurement, all but an exponentially small fraction
> of data records agree that the Stern-Gerlach effect is
> present, but it is both unnecessary and impossible, even in
> principle, to identify a specific moment at which the qubit
> wave function collapsed.
>
>The bottom line is, introductory QM textbooks make the math as
>simple as possible, at the expense of making the philosophy more
>mysterious. They're good for getting newbies started, but are
>not intended as the final word on QM.
As a former student of science whose quantum mechanical education was
arrested at the newbie stage, let me say this is fascinating stuff,
and I envy you the chance to be involved in it. May I ask where in
the spectrum of "interpretations" of quantum mechanics this new style
of computation falls? What sort of fundamental model are you applying
more detailed mathematics to to extract additional insight? The
non-relativistic many-body wave equation? What?
As for collapse, my two cents: I guess I always assumed this was a
symptom of incompleteness, and as such it never bothered me very much.
I think there was a contingent that wanted to *prove* that no more
complete description than (continuous evolution) --> (discontinuous
jump at measurement epoch) --> (repeat) was possible... but I think
history has shown this claim to be over-ambitious. I found it hard to
believe that the universe really cared enough about our "measurements"
to single them out for special treatment, and I don't think this
"hard to believe" reflects some kind of childhood fixation.
Collapse certainly plausibly reflects an incompletely characterized
system which is occasionally inspected -- my probability density for
the location of a wandering drunk may grow into a diffuse blob between
times of checking in on him and then "collapse" to his observed
location, but one hardly has raptures about quantum weirdness here.
This immediately suggests I am unaware that location for a quantum
particle between observations may not be a particularly good part of
our ontology, or even perhaps the persistence of an individual entity,
but, no... this is merely a suggestion. :-) I am aware.
Ed
