HDTenEightyP/NetNews huggingface dataset:
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: QM implies non-c photons
Date: 12 Oct 92 15:26:17 GMT
Article-I.D.: husc8.mcirvin.718903577

rschmidt@reed.edu (Rod Schmidt) writes:

>   This implies that you can get measurable amounts of photons going
>faster than c. This of course is equivalent to going backward in time.
>The grandfather paradox is likely to be a non-problem --
>you have an amplitude to go back in time and screw yourself up, and that
>simply gets added to all the other amplitudes to determine what actually
>happens.
>   Comments?

Someday I'll get around to writing a FAQ list entry on virtual
particles.  I think it needs doing.  Yes, the things Feynman was
talking about-- virtual particles-- can go faster than light.  The
remarkable thing is that it doesn't imply transmission of information
faster than light.  If I create photons at point A and time zero, and
detect them at point B at a time before d/c where d is the distance
between A and B, my detector won't register any more hits than it
would if the creation apparatus at point a were turned off.  More of
the events will be due to the process where a virtual photon goes from
A to B, but there's no way I can tell that until enough time has passed
that I can see the creation events!  

There are several ways you can think about this.  One (which I suspect
was really the way Feynman thought about it, at least in his early
work on the subject of QED) is rather literalistic:  these
particles really are flying around in crazy paths faster than light and
backwards in time, and the amplitudes add up to yield the more or less
sensible world we see, which behaves in a causal, local manner.  Another
is to speak of the virtual particles as merely a convenient bookkeeping
aid for what are really calculations involving the interactions of 
quantized fields.  The latter approach seems to me to be more generalizable;
it's the way the subject is usually taught today.  For one thing, the
picture in which particles are flying around only really arises if you
do perturbation theory, and perturbation theory isn't always a valid 
approximation (there are questions as to whether it is ever valid!)

As for the grandfather paradox, if there are such things as closed
timelike loops, a resolution something like the one you propose just
might be in order.  Virtual particles create no such paradoxes in the
first place; it's certainly a non-problem for them.
 
-- 
Matt McIrvin, posting nonsense again
From: produit@lblcdf.lbl.gov ()
Newsgroups: sci.physics
Subject: Re: OQ (Open Question) on particles
Date: 14 Oct 1992 18:35:04 GMT
Organization: Lawrence Berkeley Laboratory, Berkeley CA
Distribution: world
Reply-To: produit@lblcdf.lbl.gov ()
NNTP-Posting-Host: cdf1.lbl.gov


In article <MATT.92Oct13104824@physics16.berkeley.edu>, matt@physics16.berkeley.edu (Matt Austern) writes:
|>Path: overload.lbl.gov!dog.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!sun-barr!olivea!spool.mu.edu!agate!agate!matt
|>From: matt@physics16.berkeley.edu (Matt Austern)
|>Newsgroups: sci.physics
|>Subject: Re: OQ (Open Question) on particles
|>Message-ID: <MATT.92Oct13104824@physics16.berkeley.edu>
|>Date: 13 Oct 92 17:48:24 GMT
|>References: <phfrom.332@nyx.uni-konstanz.de> <1992Oct9.202507.22964@galois.mit.edu>
|>	<phfrom.345@nyx.uni-konstanz.de>
|>	<1992Oct13.163540.27085@galois.mit.edu>
|>Reply-To: matt@physics.berkeley.edu
|>Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
|>Lines: 20
|>NNTP-Posting-Host: physics16.berkeley.edu
|>In-reply-to: jbaez@riesz.mit.edu's message of Tue, 13 Oct 92 16:35:40 GMT
|>
|>In article <1992Oct13.163540.27085@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:
|>
|>> Hmm.  My definition was only intended to allow one to say "in this
|>> theory there are the following elementary particles: electrons and
|>> protons" or some such thing.  As soon as one has a 2-particle state it
|>> is no longer an eigenvalue of the mass operator (since the relative
|>> velocities can vary continuously, essentially).
|>
|>Actually, I've always thought that a decent definition of a particle
|>is that it's an irreducible representation of the Poincare group.
|>(With, again, the same caveat: unless you're talking about asymptotic
|>states, it's hard to figure out what really is and isn't a particle.)
|>
|>Then there's my other definition: a particle is something that you can
|>see in a bubble chamber.
|>--
|>Matthew Austern                   Just keep yelling until you attract a
|>(510) 644-2618                    crowd, then a constituency, a movement, a
|>austern@lbl.bitnet                faction, an army!  If you don't have any
|>matt@physics.berkeley.edu         solutions, become a part of the problem!
|>
Your definition of a particle as something you can see in a bubble chamber would mean that all "particles" of charge 0 wont be particles.


Nicolas
Newsgroups: sci.physics,sci.math
From: jac@ds8.scri.fsu.edu (Jim Carr)
Newsgroups: sci.physics
Subject: Re: Magnetic levitation
Date: 13 Oct 92 17:15:42 GMT
Reply-To: jac@ds8.scri.fsu.edu (Jim Carr)
Organization: SCRI, Florida State University

In article <1992Oct12.223513.23782@cs.wisc.edu> miked@phenos.physics.wisc.edu (Mike Doncheski) writes:
>Hi all!
>
>     One of my students is interested in building a simple magnetic 
>levitation system.  If my memory is working OK, I think it can be 
>done passively (using carefully shaped permanent magnets) or actively 

The former is probably easier to build.  However, the repulsion is an 
unstable equilibrium and attraction is *very* unstable because of the 
rapid variation of the force with distance.  I think the commercial 
systems work on the active principle, because you have to work real 
hard on symmetry to get repulsion to work in a passive setup.

(Levitation propulsion system use changing fields to propel as well 
as suspend the vehicle, but static is easier to build.) 

>(using electromagnets, sensor coils and some sort of feedback/logic 
>circuit).  The idea is to create a floating sculpture (the mass isn't 
>a problem, as it can be primarily styrofoam with a steel ball bearing 
>inside);  I know this is going to be difficult, but I want to give the 
>student some idea of what's involved, and let the student decide.  So, 
>I'd like to know if anyone in sci.physics land has any experience in 
>designing/building, or even a good reference about, magnetic levitation 
>systems.

My experience is in trying to design a passive system that resembles a 
mag-lev train.  Magnets in the styrofoam train and in the track repel 
and hold up the train, but keeping it centered on the rail and dealing 
with edge effects is less trivial.  Mucho experimentation required.  

A lot depends on what the support system will look like.  If it is to 
be fairly open, it will probably have to be an active system.

--
J. A. Carr                                    |  "The New Frontier of which I  
jac@gw.scri.fsu.edu                           |  speak is not a set of promises
Florida State University  B-186               |  -- it is a set of challenges."
Supercomputer Computations Research Institute |   John F. Kennedy (15 July 60)
From: corleyj@helium.gas.uug.arizona.edu (Jason D Corley )
Newsgroups: sci.physics
Subject: Re: VERY FUNDAMENTAL QUESTIONS  -    ABIAN's Comments
Summary: A physics addict mouths off
Keywords: WHY, HOW, REASON and EXPLAIN
Date: 15 Oct 92 22:10:39 GMT
Organization: University of Arizona, Tucson, AZ

In article <abian.719182300@pv343f.vincent.iastate.edu> abian@iastate.edu (Alexander Abian) writes:
>
> 
>        " WHY IT DOES "    is    " BECAUSE IT DOES "
>  
>  TIME HAS INERTIA
>
>
>   E = mcc   (Einstein)             E = m(0) exp (-At)    (Abian) 
>  THE ORIGIN OF SPECIES ... (Darwin)      THE FUTURE OF SPECIES ... (Abian)
>                                            Alexander ABIAN

But Mr. ABIAN, sir, um, I think, just from reading the
objections to your, um, your theory, that the question people
are asking is not "WHY IT DOES", which, well, isn't really a 
question anyway, I think you meant "WHY DOES IT", which isn't
much better or clearer, well, um, where was I, oh yeah, the
question people are asking is not "WHY DOES IT?", but
"Why doesn't it?"

For instance, "If your theory is true, Why Doesn't It explain
the different sizes of reactions with similar, or even identical
substances?", or, "If your theory is true, Why Doesn't It have
any substantative mathematics or falsifiable/"truth"ifiable statements
to test?", or generally dozens of other, "If your theory is true,
Why Doesn't It, [fill in blank here]?"

Just wanted to point that out.  Sir.
(A crackpot index question: if you're quoting someone else's
all-caps words, does it count towards your score?)
	Jason
	Ono-Sendai R&D
Newsgroups: sci.physics
From: gawne@stsci.edu
Subject: Nobel Prize Announcement
Organization: Space Telescope Science Institute
Distribution: na
Date: Thu, 15 Oct 1992 00:03:25 GMT

extracted from:
PHYSICS NEWS UPDATE
Number 99   October 14, 1992

THE PHYSICS NOBEL PRIZE FOR 1992 GOES TO
GEORGES CHARPAK for his numerous contributions to the instrumentation used in
experiments at high-energy accelerators. Many of the new particles discovered
in the past few decades have used detectors developed or greatly improved by
Charpak.  In particular, his development of the multiwire proportional chamber
in the 1960's allowed the trajectories of particles issuing from high- energy
collisions to be tracked with a spatial precision of less than 1 mm.  (The
measured coordinates along the trajectory of a charge particle passing through
a magnetic field can be used to compute the particle's momentum.)  Furthermore,
the rate at which the chamber could make a measurement, recover, and then be
able to make a new measurement grew to be many thousands per second. These
characteristics of Charpak's detector---high spatial resolution and high
repetition rate---were particularly important in the study of rare interactions
or the creation of short-lived exotic particles which often necessitate the use
of intense beams and the sampling of a large number of events in a short period
of time.  (For a typical account, see the article about the discovery of the Z
particle in the March 1982 issue of Scientific American.)  Indeed, Charpak's
work helped pave the way for a greater integration of computers into the
data-acquisition process.  At accelerators where millions of high-energy
collisions per second can occur and where colossal amounts of data must be
processed quickly, computers are essential.  It is estimated, for example, that
at the Superconducting Super Collider some 40 trillion bytes of information per
second will flow out of detectors monitoring the proton-proton interactions
taking place.  (Computers in Physics, Sep/Oct 1992.) Charpak, a Fench citizen,
has spent much of his career at the CERN lab in Geneva.  He was born in 1924 in
Poland and received a PhD in 1955 from the Collge de France in Paris. 
Newsgroups: sci.physics
From: johnu@syma.sussex.ac.uk (John E. Upham)
Subject: Re: 1992 Nobel Prizes: a prediction
Organization: University of Sussex
Date: Mon, 12 Oct 1992 11:51:02 GMT

From article <138426@lll-winken.LLNL.GOV>, by chaiken@cmsgee.llnl.gov (Alison Chaiken):
> Every year for the last 5 years or so I have predicted in this group
> the winners of the physics and chemistry prizes.  So far I have an
> unblemished record of being wrong every year.     Here are my
> predictions for 1992:
> 
> Chemistry: Roy Smalley and Donald Huffman, for C60 discovery

  Sorry to be pedantic but two mistakes here...
1. Its Rick E. Smalley
2. The predictor and real discoverer (he came over from the UK
and suggested the expt. to RES) was Harry Kroto.

Apart from that your posting was factual. I hope you are right in that
C60 gets the prize and that your are wrong in who gets it. If the
rightful person doesn't the credibility of the Nobel committee will
be little tarnished to say the least.

 john upham
-- 
John Upham, School of Chemistry, University of Reading, Berks., RG6 2AD, UK.
Email: scsupham%susssys1.rdg.ac.uk@uk.ac (BITnet), scsupham@rdg.susssys1 (Janet)
Voice:   +44 734 875123 x7441 (day), Fax: +44 734 311610
Newsgroups: sci.physics
From: hearns@vxcrna.cern.ch (HEARNS,J./EP)
Subject: Re: E-Mail Address for CERN
News-Software: VAX/VMS VNEWS 1.41    
Organization: European Organization for Nuclear Research, CERN
Date: Fri, 9 Oct 1992 10:41:00 GMT

In article <BvtMIn.DB@news.cso.uiuc.edu>, magdi@uxh.cso.uiuc.edu (Magdi N Azer) writes...
> 
>	In response to my post regarding MINUIT, I found that it is public
>domain, but the author did not know of an ftp site to get it from.  Does

Bzzzt. CLose but no cigar.
CERN software is copyright, and not public domain in the sense this 
chap means
(disclaimer - I dont work for CERN and am not familiar with CN division)

No FTP site exists for all and sundry to download CERN software.

CERN libraries should be quite readily available to academic institutions 
worldwide.
Quote from the HBOOK manual:
`These programs or documentation may not be reproduced by any
method without prior written consent of the DG of CERN or his delegate'
etc.

FOr details of how to obtain CERN libraries, contact:

CERN Program Library Office
CERN-CN Division
CH-1211 Geneva 23
Switzerland
From: naturman@uctvax.uct.ac.za
Newsgroups: sci.physics
Subject: Re: Schrodingers Dog
Date: 8 Oct 92 13:48:35 +0200
Organization: University of Cape Town

 
>>Physicists just don't seem to understand that probability has got to do with
>>knowledge. Probabilities are not absolute but depend on the observer. 
> Not necessarily.  If you go up to the roulette table and bet on red, you
> will win 18/37 of the time.  That has nothing to do with your knowledge
> of probability, little balls, or anything else.  It has nothing ot do
> with the croupier's knowledge.  That probability is objective: it is
> a property of the wheel and the ball, not of any observer's state of
> mind.  That probability is absolute enough to support a very large
> industry.
> 
> Now replace the roulette wheel by a device that fires photons through
> a polarising filter.  If you bet on H, you will win 1/2 of the time.
> That probability, too, is objective: it is a property of the filter
> and the photon.

You are assuming non-determinism, a rather shakey philosophical idea. If I am
not mistaken, non-deterministic non-hidden variable interpretations result
in subjective reality paradoxes. Non-deterministic hidden variable
interpreations lead to either paradoxes or conflict with experimentaly
confirmed pure QM predictions.

-- 
*****************************************************************************
* Baby Doc Naturman                                                         *
* USS Enterprise                           "It's life Jim,                  *
* Final Frontier                                  but not as we know it."   *
* naturman@uctvax.uct.ac.za                                                 *
*                                                       Spock of Vulcan     *
*****************************************************************************
From: fxt@helios.ucsc.edu (oxide owner)
Newsgroups: sci.physics
Subject: re: status quo
Date: 11 Oct 1992 21:31:49 GMT
Organization: UCO/Lick Observatory
Distribution: world
NNTP-Posting-Host: helios.ucsc.edu

> abian@iastate.edu (Alexander Abian)
>    THE TENDENCY OF MAINTAINING THE STATUS QUO,  REACTION TO PROVOCATION 
>            AND THE TENDENCY OF MAINTAINING AGAIN A STATUS QUO
> 
> is to me the most basic PRINCIPLE in matters pertaining to all events:
> 
> No physics or mathematics can explain better the real 
> reason which governs the action of an A  or  H bomb.  They may quantify but 
> they do not explain.  The above Principle explains!
>                                          Alexander ABIAN    

physics is a quantitative science. the quantifying measurement and/or 
calculation is the explaination. please provide a measurement or a computation 
of an H bomb utilizing your principle. 

perhaps you should have been at los alamos and saved everyone a lot of work. 
i can see hans bethe slapping his forehead going "yes, the tendancy of 
maintaining the status quo; that explains it!".

fxt
Newsgroups: sci.physics
From: snyder@henry.ece.cmu.edu (John Snyder)
Subject: Re: 1992 Nobel Prizes: a prediction
Organization: Electrical and Computer Engineering, Carnegie Mellon
Distribution: na
Date: Fri, 9 Oct 1992 05:08:07 GMT

In article <92191@netnews.upenn.edu> weemba@sagi.wistar.upenn.edu (Matthew P Wiener) writes:
>In article <8OCT199210452292@csa2.lbl.gov>, sichase@csa2 (SCOTT I CHASE) writes:
>>but not complete yet.  They do, however, confirm the original work of 
>>Ray Davis.  It's possible that he gets the prize for discovering the
>>solar neutrino deficit.
>
>I think Davis and Bahcall are long overdue for a joint prize.  Not to
>be shared with GALLEX or any other newcomers.
>
>>In physics they have an excellent record.  With few exceptions, (who ever
>>heard of Jean Baptiste Perrin?)
>

I believe that the one that fewest people have heard of is Dahlen,
who go the prize for "improvements to coastal lighting" (I believe
that was for some kind of gas flow regulator for use in the
lights in lighthouses.) [Anyone know any more about this one?]

John
snyder@henry.ece.cmu.edu
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: Magnetic levitation
Date: 13 Oct 92 20:46:18 GMT
Organization: University of Virginia

In article <11105@sun13.scri.fsu.edu> jac@ds8.scri.fsu.edu (Jim Carr) writes:
>In article <1992Oct12.223513.23782@cs.wisc.edu> miked@phenos.physics.wisc.edu (Mike Doncheski) writes:
>>Hi all!
>>
>>     One of my students is interested in building a simple magnetic 
>>levitation system.  If my memory is working OK, I think it can be 
>>done passively (using carefully shaped permanent magnets) or actively 
>
>The former is probably easier to build.  However, the repulsion is an 
>unstable equilibrium and attraction is *very* unstable because of the 
>rapid variation of the force with distance.  I think the commercial 
>systems work on the active principle, because you have to work real 
>hard on symmetry to get repulsion to work in a passive setup.

     I don't think six degree-of-freedom magnetic levitation is possible
     with permanent magnets, symmetry or not because all configurations
     are unstable.  Location of such a proof escapes me at the moment,
     but I'm pretty sure it exists.

     Some commercial systems commercial systems  use a thrust bearing to
     reduce the number of degrees of freedom, but a number simply use
     active control.  You have the additional side-effect with active control 
     of being able to reduce or eliminate resonant vibrations.
>
>My experience is in trying to design a passive system that resembles a 
>mag-lev train.  Magnets in the styrofoam train and in the track repel 
>and hold up the train, but keeping it centered on the rail and dealing 
>with edge effects is less trivial.  Mucho experimentation required.  

     I believe that you still need the equivalent of a thrust bearing to 
     reduce the numbers of degrees of freedom (i.e. it has to be resting on 
     something to get the other degrees of freedom via permanent
     magnets).

                             dale bass
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
Newsgroups: sci.physics
From: cabanc@wkuvx1.bitnet
Newsgroups: sci.physics
Subject: Kids and science (was Mattel)
Date: 11 Oct 92 02:03:47 GMT
Organization: Western Kentucky University, Bowling Green, KY

On the Barbie comments flying on this network, a  few comments from a
physic major/math minor and mother.  If Mattel is offering a Barbie
that says "Math is tough" ( I missed the original message). I'd jolly
well like to know what tone its said in.  But hearing one in my house
would probably send me through the roof.  an additional "but I'm
working hard on it"  is all it would take.
	For those of you who don't think that popular culture
(commercials, toys, movies, etc. ) don't affect (or is it effect?) children's
thought processes, oh boy, do any of you have kids?  Have you ever
gone shopping with a 6-10 year old?  Have your ever heard kids singing
jingles, repeating lines from movies and tv, (I finally broke my son
from saying "hasta la vista, baby" with an austrian  accent, now my
daughter is starting to say opposite things with a "not" on the end.)
And my kids don't watch the national average on TV. They pick most of
it up from their friends.
	I realize this may be far afield from this network, but
aranything that lessensr mystifies science and math doesn't help
anybody.  And talking of kids TV why do they have mad scientists or
the good scientists are such geeks?   
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Understand...!!!!
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Wed, 7 Oct 92 16:57:27 GMT

In article <1992Oct7.061158.15794@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:
>Most people on sci physics have an idee fixe or two. Try posting
>something of the form "Hey, I hear that the gurus at Princeton think
>that the loop approach to quantum gravity is nonsense" if you doubt
>this. :)

Heh.  You are confusing my idees fixes with my current topic of research.
From: chaiken@cmsgee.llnl.gov (Alison Chaiken)
Newsgroups: sci.physics
Subject: Re: 1992 Nobel Prizes: a prediction
Date: 9 Oct 92 14:59:50 GMT
Organization: Chemistry and Materials Science, LLNL


>In article <138426@lll-winken.LLNL.GOV> chaiken@cmsgee.llnl.gov (Alison Chaiken) writes:
>>Chemistry: Roy Smalley and Donald Huffman, for C60 discovery

In article <1992Oct8.191717.17193@hyper.hyper.com> slee@hyper.UUCP (Thomas Slee) writes:
>Seems to me that if C60 is being thought of then H. W. Kroto should
>be in the list.  Also, if Huffman, why not Kratschmer?  I think
>I see a case of the well-known "non-Americans don't count" syndrome
>here: only Americans suggested from international partnerships.  
>			Tom Slee

I'm all for Kroto and Kratschmer winning if they deserve it.  Note
that I posted predictions of whom I thought WOULD win, not who I
thought DESERVED to win.  My predictions were based on my past
observations of the Nobel Committee, not any judgement of the relative
contributions of the collaborators.  [See my past posting on von
Klitzing winning without Dorda and Pepper.]  If I picked who I thought
deserved to win, I'd be liable to pick completely different people
that you have never heard of.

Actually I think Kroto is the most deserving of the C60 collaborators
because of the excellent talk he gave at the March meeting last year.
Not only was it possibly the most humorous physics presentation I've
ever heard, but I was impressed by the fact that he did not take the
opportunity to play up his role in the discovery.    That's why I
think he won't win.    

As someone has already pointed out to me by mail, Smalley is Richard,
not Roy.  Once he wins we will all be able to remember his name.
Alison Chaiken				chaiken@cmsgee.llnl.gov
(510) 422-7129				OR alison@wsrcc.com
(510) 422-7300 (FAX)			
Live fast, die young, leave a long publication list.