HDTenEightyP/NetNews huggingface dataset:
From: bob@1776.COM (Robert Coe)
Newsgroups: sci.physics
Subject: How moderation would work
Date: Tue, 12 Jan 93 13:50:21 EST
Distribution: world
Organization: 1776 Enterprises, Sudbury MA

There's been a lot said recently to the effect that the panel of moderators
would (or should) vote on whether to accept a particular article.  Surely 
that would be too cumbersome and slow!  It would (IMO) make much more sense
to allow any member of the panel to decide on any article, bouncing it to one
or more of the others only if he didn't feel qualified to make the call.  The
full panel would deal only with complaints that one or more of their number
was being too lenient or too strict.

   ___            _                                           -  Bob
   /__) _   /    / ) _   _
(_/__) (_)_(_)  (___(_)_(/_______________________________________ bob@1776.COM
Robert K. Coe ** 14 Churchill St, Sudbury, Massachusetts 01776 ** 508-443-3265
From: atems@igor.physics.wayne.edu (Dale Atems)
Newsgroups: sci.physics
Subject: Re: Quantum Collapse and Bell's Inequality (Attn: Robert Firth)
Date: 12 Jan 93 20:04:33 GMT
Organization: Wayne State University, Detroit, MI

I'm posting this here because my mail software crapped out due to
network problems when I tried to reply by e-mail.

> Place in Kansas City a Friedman-Clauser apparatus that emits pairs of
> photons in opposite directions, towards New York and Los Angeles.  Each
> pair is in an arbitrary state of polarisation, but both photons will be
> in the same state of polarisation.  Call the photons Castor and Pollux
> (what else?).  If we use the (|h>,|v>) basis, their wave equation is
> 
> 	kh.|hc>.|hp> + kv.|vc>.|vp>
> 
> with arbitrary coefficients k.

Thanks for your reply. For the case Paul and I were discussing each
member of a photon pair is sent in the opposite direction, c labels
the photon detected in (say) NY and p the one detected in LA. '+'
denotes (say) right-circular polarization, '-' denotes left-circular
polarization. The wave function is

	2^(-1/2) [ |c+>.|p-> - |c->.|p+> ] .

My question is how to predict the probability of finding c linearly
polarized along a and p linearly polarized along b, where a and b
are arbitrary directions, not necessarily perpendicular.

To me this sounds analogous to the question of how to predict, for a
singlet-state pair (c,p) of spin-1/2 particles, the probability that c
will have S.a = +1/2 and p will have S.b = +1/2. That calculation
can be done using traditional QM, without bringing in the state of the
measuring apparatus after the measurement. You just take the singlet
wave function, expand the |c> kets in the a basis, the |p> kets in the
b basis, and pick off the coefficient of the term where both are +1/2.

Is the photon case essentially different? I suspect not, but I would
have to do some digging I don't have time for right now to prove it.
Do you know the answer?

Dale

------
Dale Atems
Wayne State University, Detroit, MI
Department of Physics and Astronomy
atems@igor.physics.wayne.edu
From: rubio@pine.circa.ufl.edu (RUBIO)
Newsgroups: sci.physics
Subject: two point masses in an expanding universe
Date: 5 Jan 93 17:47:49 GMT
Reply-To: rubio@pine.circa.ufl.edu
Organization: University of Florida  (ufl.edu)
News-Software: VAX/VMS VNEWS 1.3-4


	This is a simple question that bothers me a lot:

Imagine there are two (point) masses separated by a finite distance in an 
expanding universe. The distance between the two masses increases and so 
does their (relative) velocities, both of which imply that the energy of 
one of them with respect to the other is increasing.

This energy is, therefore, not conserved. Where does it come from (go?)?
Is it the energy from the expansion? I would appreciate any comments. I've 
already looked at the FAQ but it didn't help.

This is a closed system, (for simplicity I'll make the space closed in the 
spacetial sense). The Super-Hamiltonian vanishes (therefore it's conserved).
After I "gauge" the theory I end up with a non-conserved energy. This 
implies the energy is going into the gauged degrees of freedom. Doesn't it?

Thanks for any help. Even flames will be nice (I hate it when I don't get 
any reponses).

			-jose a. rubio-
From: mcirvin@husc8.harvard.edu (Matt McIrvin)
Newsgroups: sci.physics
Subject: Re: Recommend high school physics text?
Keywords: text
Date: 8 Jan 93 22:00:59 GMT
Article-I.D.: husc.mcirvin.726530459

rfeldman@theory.TC.Cornell.EDU (Bob Feldman) writes:

>My son is frustrated because his high school physics textbook doesn't
>explain how mathematical formulas have been derived.  Can anyone recommend
>a textbook that will give clear, concise, mathematical derivations
>of formulas used in high school physics?

First of all, it's important to understand what he means by derivations
of formulas.  Many expressions in physics were never derived to begin
with-- they were postulated and shown to correspond to experiment.  To
make matters less clear, there are often many equivalent ways of
formulating a physical theory that make different statements about
what is postulated and what is derived from the postulates.

For instance, in the line of reasoning usually given in high-school
physics textbooks, Newton's laws aren't derived at all, and neither is
Coulomb's law or Newton's expression for the gravitational force.  
Formulas that just define a quantity, like kinetic energy, aren't
derived either; they are definitions.

It's possible to restate classical mechanics so that some of these
formulas are actually derived consequences of something else, such
as Lagrangian mechanics.  But the way described above is how it's 
usually taught.
 
Now, once you have those postulates and definitions, you can derive
consequences-- and a textbook that stated consequences without at
least giving some idea of the derivation would be a poor textbook
indeed.  Does he mean that the book's derivations are insufficiently
rigorous, or that purely mathematical statements aren't being properly
justified?  If so, it might be a consequence of a precalculus curriculum,
in which case I would advise looking in college textbooks (and perhaps
learning the elementary calculus necessary to follow the discussion).

If, on the other hand, he means that the textbook isn't deriving things
like F = ma, I would say that within the logical structure used by the
textbook (and by Newton) this is not a derived statement, but something
*postulated* to explain some phenomena.  The justification comes not
from a mathematical argument, but from experiments and observations
in the physical world.
-- 
Matt McIrvin         I read Usenet just for the	tab damage!
==== =======         = ==== ====== ==== === === === ======= 
Xref: sparky sci.physics:22409 news.groups:25270
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics,news.groups
Subject: Re: sci.physics.research: proposed panel of moderators
Date: 9 Jan 1993 21:40:14 GMT
Organization: Intel Corp., Chandler, Arizona
NNTP-Posting-Host: stealth.intel.com

In article <C0KH6x.4xr@news.cso.uiuc.edu> rvc40592@uxa.cso.uiuc.edu (Bob Cadman) writes:
>sidles@stein.u.washington.edu (John Sidles) writes:
>>Sounds like a prescription for a self-perpetuating
>>aristocracy to me.  Good thing the Constitution isn't set up this way.
>
>It seems to me that in its own special way, Usenet is a
>self-perpetuating aristocracy.  Deal with it.

He is, Wilde, he is.

				--Blair
				  "Oh, great; the net.cops have
				   given way to the net.snobs..."
Newsgroups: sci.physics
From: darice@yoyo.cc.monash.edu.au (Fred Rice)
Subject: Where's the FAQ ?
Keywords: FAQ
Organization: Monash University, Melb., Australia.
Date: Mon, 11 Jan 1993 12:37:25 GMT

I haven't seem the sci.physics FAQ posted yet.... have I missed it? 

If it hasn't been posted yet, does anyone know when or if it will be
posted, or where I can get it from?

Thanks in advance if anyone can help, 

 Fred Rice
 darice@yoyo.cc.monash.edu.au   
Newsgroups: sci.physics,news.groups,sci.misc
From: snyder@henry.ece.cmu.edu (John Snyder)
Subject: Re: sci.physics.research: proposed panel of moderators
Organization: Physics Department, Carnegie Mellon University
Date: Thu, 7 Jan 1993 23:52:39 GMT

In article <MATT.93Jan6101442@physics2.berkeley.edu> matt@physics.berkeley.edu writes:
>There hasn't been very much discussion about sci.physics.research
>lately, but most of the comments seem to have been positive, so I will
>probably post a CFV in a week or two.  First, though, we need a little
>bit more detail on who the moderators will be, and what the guidelines
>for posting will be.  
>
>In a day or two, I'll be posting a set of guidelines for articles
>submitted to sci.physics.research, but first, here's the proposed
>panel of moderators.
>       John Baez    (jbaez@math.mit.edu)
>       Dale Bass    (crb7q@virginia.edu)
>       Bill Johnson (mwj@beta.lanl.gov)
>       Lee Sawyer   (sawyer@utahep.uta.edu)
>If one moderator has to quit, the others will choose a replacement.
>
>The intent is that this panel be reasonably diverse in terms of
>research interests; each of these people wrote up a "microCV" that
>tells a bit about their background and what they do.
> 
>----------------------------------------
>John C. Baez
>BA mathematics Princeton U. 1982
>PhD mathematics MIT 1986
>Associate Prof. Dept. of Math. U. C. Riverside
>Constructive quantum field theory, nonlinear wave equations, and
>    the relationship of knot theory to quantum gravity
>----------------------------------------
>
>----------------------------------------
>Cameron 'dale' Bass
>B.S. Aerospace Engineering, UVa
>Graduate Research Assistant, University of Virginia;  
>    Ph.D. expected early 1993 in Mechanical and Aerospace Engineering;  
>Research interests: fluid dynamics, electromagnetism, acoustics
>----------------------------------------
>
>----------------------------------------
>Bill Johnson
>Staff member [project leader] at Los Alamos National Laboratory;
>Ph.D., nuclear chemistry, Univ. of Rochester, 1979; 
>Research interests: basic and applied nuclear physics, nuclear safeguards
>----------------------------------------
>
>----------------------------------------
>H. Lee Sawyer, Jr
>B.S. Northeast Louisiana University (1985)
>Ph.D. Florida State University (1991)
>Experimental high energy physicist (we haven't perfected them yet...)    
>Member of the E711, ALEPH, D0, and SDC experimental collaborations.      
>----------------------------------------
>--
>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!


I don't see anyone here representing the Condensed Matter Physics community,
either theoretical or experimental.  Is this by design, or did no Solid
State people volunteer?


John
snyder@henry.ece.cmu.edu

P.S. No, I don't think I'm volunteering

Xref: sparky sci.physics:22138 sci.astro:13672
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics
Subject: Re: A proof that quantum mechanics is an incomplete theory
Date: 7 Jan 1993 03:07:24 GMT
Organization: Intel Corp., Chandler, Arizona
NNTP-Posting-Host: stealth.intel.com

But then, so is classical mechanics.

So what's your point?

				--Blair
				  "Currently mapping [0,1)
				   to [0,2) with ease..."
Xref: sparky sci.physics:22545 news.groups:25386 alt.sci.physics.new-theories:2730
From: kring@efes.physik.uni-kl.de (Thomas Kettenring)
Newsgroups: sci.physics,news.groups,alt.sci.physics.new-theories
Subject: Re: How about sci.physics.speculation as well?
Date: 12 Jan 93 00:32:48 GMT
Organization: FB Physik, Universitaet Kaiserslautern, Germany

I took sci.misc out of the header.

In article <1993Jan8.023635.8057@netcom.com>, noring@netcom.com (Jon Noring) writes:
[..]
>Now, even with this tirade, I have no problem with a moderated newsgroup
>devoted to discussion of "orthodox" physics only (I won't even attempt to
>define orthodox, btw), as long as this is stated above board.  And let me
>go on to offer an olive branch and propose that along-side a
>sci.physics.research (it should really be called sci.physics.orthodox), that
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>a parallel moderated newsgroup, called sci.physics.speculations be created
>as well (I'd be happy to be a moderator for such a group).

sci.physics.orthodox is a bad name, as it has a negative taste.
("Ah, that's where the old orthodox physicists post, those with the
spider webs on their paradigms.")  It's almost as bad as calling your
proposed s.p.speculations group s.p.crackpot instead.

--
thomas kettenring, 3 dan, kaiserslautern, germany
"Pink"
(Peter Ustinov's answer to "Skin Color" on his US immigration form)
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: knots and stat.mech.
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Tue, 12 Jan 93 22:45:47 GMT

In article <93012.111528U16072@uicvm.uic.edu> <U16072@uicvm.uic.edu> writes:
>In article <1993Jan11.210616.12263@galois.mit.edu>, jbaez@riesz.mit.edu (John C.
>Baez) says:
>>Vijanathi Chari and Andrew Pressley are writing a very good book on
>>quantum groups, but it'll be a while before this gets published.
>
>If it is not yet published , how can you (j. Baez) be sure it's a very
>good book?

I read it.


Newsgroups: sci.physics
From: jkodish@muskwa.ucs.ualberta.ca (Kodish Jason)
Subject: Gravitaional lasers
Organization: University Of Alberta, Edmonton Canada
Distribution: sci
Date: Tue, 5 Jan 1993 22:49:10 GMT

 
Is it possible to generate tightly confined beams of gravitational waves analogous to laser beams? If so,what are the effects? Is it possible to get access to online physics journals through UNIX,and how do I do it?
Newsgroups: sci.physics,alt.sci.physics.new-theories,alt.conspiracy,sci.skeptic,alt.paranormal,alt.alien.visitors
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: POP! FIZZZ.... PSI WARS!
Organization: Whole Earth 'Lectronic Link
Date: Tue, 5 Jan 1993 04:46:42 GMT


POP! FIZZ....REVIEW
Jack Sarfatti
Editor
Vol.1 No.2 1993
#2 PSI WARS!
from WALL STREET JOURNAL, Jan 4, 1993

Quotes are from Nonlethal Arms written by Thomas E. Ricks, front page.
"... a new electromagnetic 'pulse' generator that disables equipment
without hurting people."

Better than the neutron bomb which did just the opposite.

"...'combustion inhibitors' that stop the engines of movint vehicles, as
well as chemicals that crystallize and destroy certain kinds of tires ...
information-age wars in which the emphasis is on paralysing the adversary,
not necessarily destroying him. .... John Alexander began thinking about
them ... in 1980 he published an article in Miltary Review ... about 'the
new mental battlefield,' which he said could involve telepathy or weapons
that interfered with the brain's owm electrical activity .... 'soft-
kill'... In 1988, Col. Alexander ... joined Los Alamos National Laboratory,
where he is attached to the special technologies group ...   his interest
in parapsychology led him to collaborate ... with Janet Morris  ... She
enlisted Ray Cline, a well-connected former deputy director of the Central
Intelligence Agency, who was able to open doors at the White House and the
Pentagon . ....The Pentagon ... cut out Janet Morris and Ray Cline, who
were perceived as meddlesome and uncontrollable ....

Infrasound: Very low frequency sound ... causing disorientation, nausea,
vomiting or bowel spasms ...

Computer virus technology ... focuses on computer systems which control
fire support systems, data transmission .... .... worm which may remain
hidden until the system is used..."
Newsgroups: sci.physics
Newsgroups: sci.physics
Subject: Newton's birthday
From: bigbro@netlink.cts.com (Kenneth Sullivan)
Date: Mon, 04 Jan 93 14:46:39 PST
Organization: NetLink Online Communications, San Diego CA

When is Issac Newton's birthday?  I have heard from some people its 
12-25, and from others its today (1-4) does anyone here know for sure?

--                    
INTERNET:  bigbro@netlink.cts.com (Kenneth Sullivan)
UUCP:   ...!ryptyde!netlink!bigbro
NetLink Online Communications * Public Access in San Diego, CA (619) 453-1115
From: ewright@convex.com (Edward V. Wright)
Newsgroups: sci.physics
Subject: Re: Accellerating Spaceship (yet another bird in a plane)
Date: 6 Jan 93 20:39:35 GMT
Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

In <6850@tuegate.tue.nl> johan@blade.stack.urc.tue.nl (Johan Wevers) writes:

>Yes, if it was true. But matter with a negative mass would react just
>the same as matter with a negative electrical charge. 2 negative
>{charged or mass} particles attract each other, 1 negative and one positive
>{charged or mass} particle repulse each other. 

No, two negative charges repel one another.  Two 
opposite charges *attract* one another.

Gravity does not behave that way, since two positive masses
attract instead of repelling.

>* J.C.A. Wevers                *   The only nature of    * 
>* johan@blade.stack.urc.tue.nl *   reality is physics.   * 

Time to dig out that high-school textbook and start brushing up.
From: paul@mtnmath.UUCP (Paul Budnik)
Newsgroups: sci.physics
Subject: Re: Quantum Collapse and Bell's Inequality
Date: 12 Jan 93 18:24:34 GMT
Organization: Mountain Math Software, P. O. Box 2124, Saratoga. CA 95070

In article <1993Jan12.080512.14221@cs.wayne.edu>, atems@igor.physics.wayne.edu (Dale Atems) writes:
> As a followup to my earlier post:
>  
> Paul, I think the crux of any disagreement between us is whether you need
> to invoke quantum collapse to predict the correlations that violate Bell's
> inequality. This is *definitely* untrue for the spin-1/2 experiment I
> described.

Again the experiment you described does not violate Bell's inequality
because it lacks controllable parameters and thus does satisfy the
conditions under which that inequality is predicted to hold.

> The probability densities (space part of the wave function) at
> each site are irrelevant in that case, to get the correlations one
> makes use only of the spin part.

What is crucial is the probability that one will observe a 
certain spin or a certain polarization at a given time and location.
You cannot separate these out in understanding how the predictions
come from the theory. The theory predicts probabilities for a detection
event.

The locations and times of the detections are central to the question
of whether Bell's inequality is violated. Correlations
alone cannot violate this inequality because the inequality
is only predicted to hold under specific conditions that involve space
time and controllable parameters.

>[...]  
> Yes, the detection event is problematic. But you don't need to consider
> it at all to predict the measured correlations.

Again you can generate shorthand methods to predict the correlations and
this can mask the theory that those methods come from. However to see
whether collapse is needed you have to go back to the original theory
and understand how those methods are derived from that theory.

Paul Budnik
Newsgroups: sci.physics
From: hagerman@ece.cmu.edu (John Hagerman)
Subject: Re: Yet Another Preposterous Post
Organization: Carnegie Mellon University
Distribution: sci
Date: Thu, 7 Jan 1993 19:32:54 GMT

dseeman@novell.com (Daniel Seeman) writes:
>
> [I write]:
> >"... what happens if we make it a postulate and explore the
> >implications?" ... The second step is hard; perhaps beyond most
> >readers of sci.physics, but surely not beyond the experts.
>
> For the record, I take exception to that remark about this
> information being "...beyond most readers...(except) experts..."
> Remember, if a subject is too difficult for the instructor to teach,
> probably the instructor does not understand the material herself.
>
> Your audience is well educated, don't forget that...
>
> dks.

I must not have been clear; I don't think the _information_ is beyond
the typical reader of sci.physics, I think that the _derivation_ of
the information (may) be beyond the typical reader.  I don't say this
to denigrate the readers of sci.physics, but rather to point out that
it is not surprising to see posts that present an idea without a full
development of the implications.

- John
--
hagerman@ece.cmu.edu
Organization: Penn State University
Date: Thu, 7 Jan 1993 14:14:58 EST
From: <CCB104@psuvm.psu.edu>
Newsgroups: sci.physics
Subject: "SPIN," Micro- vs. Macroscopic . . . .

What's the difference between the spin of a globe or
disk (e.g. beachball or frisbee), say, and the spin of an
electron, photon, phonon, Bloch spin wave, proton, etc.?

Thanks,

Carey
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics
Subject: Re: Speed of gravity (Re: Davis Mechanics (was Re: John Woods Campbell))
Date: 7 Jan 1993 23:08:19 GMT
Organization: Intel Corp., Chandler, Arizona
NNTP-Posting-Host: stealth.intel.com

Hmm.

Ol' Dr. Park, back at the U. of Md., got tenure by performing
an experiment which changed the law of gravity from GmM/r^2.0000...
to GmM/r^2.000000...

His apparatus was a SQUID in a vibration-damping container
hung about 3 m away from a gigantic pendulum (1500 lbs of
steel or aluminum, I forget which).

[His point was that the inverse-square law means that gravity
is solenoidal, so if you measure deformation of six squids,
each on the face of a cube, they integrate to zero, which
they did, to two more significant digits than anyone's ever
measured such a thing before...the pendulum was used to
give a large amplitude to the useful components of the
gravity so that noise in the system could be easily
filtered out.]

The question is, could you measure the phase between two
measurements taken simultaneously at 3 m and 4 m, given the
same apparatus?  The amplitudes at this range are in the
ratio 9:16, or about 1:2, which would leave the smaller of
them well within the measurement range of Dr. Park's squids
(if his oscilloscope was to have been believed).  We could
then get a measure of the time taken to travel between them
by the gravitational intensity fluctuation as it propagated
away from the pendulum.

If we aim for a ballpark of 3e8 m/s, then 1m is about 3e-9
s, or about three nanoseconds (Grace Hopper would confirm
this, God rest her code), which is pretty bloody huge by
modern timing standards.  The computer under your fingers
is full of transistors which perform boolean operations
faster than that.  We could easily get lab timers with
sub-picosecond resolution and give ourselves 3-4
significant digits of precision.  If we're really nice
about it, we could probably get femtosecond-resolution
differential timers and our pictures in the Encyclopaedia
Brittanica.

Hay, who's got a DARPA grant form handy?

				--Blair
				  "The things you pick up from a
				   lifetime of dumpster diving."
Newsgroups: sci.physics
From: nariani@utdallas.edu (Sushil Nariani)
Subject: Re: Sarfatti Forteana
Organization: Univ. of Texas at Dallas
Date: Tue, 5 Jan 1993 21:12:16 GMT

In article <103669@netnews.upenn.edu> weemba@sagi.wistar.upenn.edu (Matthew P Wiener) writes:
>In article <1992Dec30.223943.3346@trl.oz.au>, jbm@hal (Jacques Guy) writes:
>>If that is indeed the true etymology of "Tsarfat", it would be the only
>>case I know of (and I'm into comparative linguistics) where a word has
>>been borrowed backwards.
>
>Oh come on.  Within physics (ha! hahaha! physics in sci.physics!) there
>is a very famous example.  Ohm (German) became mho (English and ??), the
>pre-SI unit of conductance.
>-- 
>-Matthew P Wiener (weemba@sagi.wistar.upenn.edu)



	This reminds me of the days at IIT(Bombay). There was this prof for 
	Basic Circuits, M.S.Kamath, who was an absolute master of phasors
	et al and notorious for "raping" peepuls in exams. He was dubbed
	"Homo" for obvious reasons and his signature was the symbols
	for "Ohm-Mho"

	Sushil