HDTenEightyP/NetNews huggingface dataset:
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: Space Station & APS
Organization: University of Virginia
Distribution: na
Date: Fri, 31 Jul 1992 18:40:43 GMT

In article <25114@dog.ee.lbl.gov> sichase@csa2.lbl.gov writes:
>In article <1992Jul30.214339.38024@ns1.cc.lehigh.edu>, jmp1@ns1.cc.lehigh.edu (JEFFREY MICHAEL PARSONS) writes...
>>Can anyone confirm what Sen. Grahm (Texas) said on CBS This Morning (7/30/92)?
>>I believe that he said that governmental funding of science research has gone
>>from a former (stable) 5% of the budget to 1.8% (1.6% without the SSC) under
>>the current Congress.  He noted that this trend appears to be continuing.  I
>>would also add that it is my impression that a smaller percentage of federal
>>science funding is going to physics.  Does anyone have a source which confirms
>>or refutes these facts?  Dale, what does your crystal ball have to say? :-)
>
>This probably refers to the shift in a large number of research dollars into
>the defense budget since the Reagan years.  I doubt is real dollar total
>expenditure for basic research has gone down.  And the budget hasn't
>grown *that* much.

     I agree that the budget has not grown enough to do this entirely
     (roughly $600 billion in 1980 to roughly $1.5 trillion today).
     But, it is difficult to determine the meaning of the numbers without
     the myraid assumptions that go into them.  I'm sure Mr. Bumpers
     (a SSC opponent) has similarly shocking numbers that are probably
     similarly worthless in the way that they are always presented, without
     good context.

>-Scott (not-the-Dale)
                                 dale bass  (the-Dale-not-Bumpers)
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: preece@npdiss1.StPaul.NCR.COM (Bently Preece)
Newsgroups: sci.physics
Subject: Re: Twin Paradox
Date: 27 Jul 92 17:29:24 GMT
Reply-To: preece@npdiss1.StPaul.NCR.COM (Bently Preece)
Organization: NCR Network Products Division, St. Paul MN, USA

In article <BrKppo.5Au@well.sf.ca.us>, metares@well.sf.ca.us (Tom Van Flandern) writes:
     
     Earlier I posed a symmetrical version of the twins paradox:
     
     also Richard.Mathews@West.Sun.COM (Richard M. Mathews) replied:
     > What's your paradox?
     
     Nonetheless there is a problem here

Please excuse me from interrupting your discussion -- I'm just an
ignorant computer nerd -- but someone has missed something, and
that someone might be me.

If all distances were given in the Earth frame, then the 4 light
years between T1 and T2 would be contracted from the distance which
T1 and T2 measure.  That is, T1 and T2 would think they were actually
28 light years apart.  And similarly, T1 and T2 would see the 4
light-year distance between Earth and Alpha Centauri contracted to
only 4/7 light years.

Earth and T1 would agree that T1's clock reads 4/7 years (close enough)
when T1 reaches Alpha Centauri, but Earth would think it's because T1's
clock is running 1/7 speed, while T1 would think that Alpha Centauri
is only 4/7 light-years away.

Similarly, Earth and T1 would agree that Earth's clock reads about
4 years when Earth reaches T2.  Earth would think T2 is 4 light years
away.  T1 would think Earth traveled 28 light years, but that Earth's
clock is running slow.

-- 
-------------  
Bently Preece                                      NCR Network Products Div.
software engineer                                      2700 Snelling Ave. N.
b.preece@StPaul.NCR.COM                               St. Paul, MN USA 55113
Newsgroups: sci.physics
From: yaron@astro.as.utexas.edu (Yaron Sheffer)
Newsgroups: sci.physics,sci.astro,sci.philosophy.tech,talk.religion.misc
Subject: Re: Structure of Time
Date: 29 Jul 92 15:29:37 GMT
Followup-To: sci.physics
Organization: University of Texas, McDonald Observatory

In article <8eROWxG00WB7AfWl5g@andrew.cmu.edu> st0o+@andrew.cmu.edu (Steven Timm) writes:
>Could it be that the reason fewer young ladies are interested in 
>physics and cosmology nowadays is because they receive such rough
>treatment at the hands of know-it-all netters?

Nope. I'm sure lots of lady-she-professors out there also laugh at these
non-sensical postings, but presumably avoid harsh postings the way
men can post ;-)

>  It seems to me that for a little 
>girl of 5 years old to even know about neutrinos and radiation and
>electricity  is quite a bit to ask.

Geez, you actually BELIEVED this story? A boy with the same "knowledge"
on the net would have been equally blasted. Actually, it's not the girl
that was ill-treated, but the sopposed parent, AND HE IS A MALE, for
God's sake!
 
>Why not the space potato?

For a good reference, read Quayle, D. (1992) in Newspaper, Anywhere.

Ronny
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics
Subject: Re: mass of quarks?
Keywords: quark property
Date: 29 Jul 92 23:44:26 GMT
Distribution: usa
Organization: Intel Corp., Chandler, Arizona

In article <25025@dog.ee.lbl.gov> sichase@csa2.lbl.gov writes:
>Loosely speaking, you heat up some matter until the quarks and qluons are
>liberated. If they are massive, then you heat things up some more and when
>chiral symmetry is restored they lose their mass.  Cute, huh? 

What do you mean, "heat?"

				--Blair
				  "Two eggs, over easy, wheat
				   toast, and a small quark..."
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Defining Photons
Date: 28 Jul 92 19:32:28 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa2.lbl.gov
NNTP-Posting-Host: 128.3.254.197
Keywords: Relating photons E=MC^2 criticism
News-Software: VAX/VMS VNEWS 1.3-4   

In article <27JUL199219012221@zeus.tamu.edu>, dwr2560@zeus.tamu.edu (RING, DAVID WAYNE) writes...
>In article <24926@dog.ee.lbl.gov>, sichase@csa3.lbl.gov writes...
>>What is classical in a cloud chamber (in which by the way, no one has ever
>>seen a W!) is not the charged particle but the droplets which condense on the
>>ionized nucleation sites.  The W itself is behaving quite nonclassically.
> 
>? It follows a definite path, even if it was prepared as a plane wave. It
>will not interfere with other paths. What does the poor guy have to do to
>prove he's classical?

The W was most certainly not prepared as a plane wave.  And I can assure
you that the momentum and position resolution of a cloud chamber are nowhere
near that required to test any uncertainty relations.  

Incidentally, you never see a track from a W, even in a modern detector,
because it decays *way* too soon.  I realize that we have suspended some
rules of physics here for the sake of discussion, but I don't want anyone
to be mislead that a W can really travel meters through a detector.

-Scott

--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: sci.physics
From: MALLON@rzmain.rz.uni-ulm.de (Mallon Rainer)
Subject: WANTED
Organization: University of Ulm, Germany
Date: Wed, 29 Jul 1992 16:05:13 GMT
X-News-Reader: VMS NEWS 1.23

----------
  WANTED
----------

  We are looking for a program called "CONTIN" by Provencer. It is said to
  do measures on relaxation processes and does contain some fourier -
  transform between time and frequency. Who can help ?

  Another question : who knows about Cirrus Logic, Japan ? Where else can this
  company be located ?

  Thanks for reading,
                  RaMa.


 


-----------------------------------------------------------------------
| Rainer "RaMa" Mallon           |       I am an instant swimmer ...  |
| University of Ulm, Germany     |       ... just add water !         |
| Department of Applied Physics  |                                    |
-----------------------------------------------------------------------
                   
Newsgroups: sci.physics
From: danforth@riacs.edu (Douglas G. Danforth)
Subject: Bell dethrowned, part II
Keywords: EPR, Bell, Aspect, Quantum mechanics
Organization: RIACS, NASA Ames Research Center
Date: Mon, 27 Jul 92 18:05:38 GMT


I see that it is necessary to slightly expand my previous posting to
explicitly mention the issue of joint conditionalization.  The model and
conclusions are unchanged.


----------------------------------------------------------------------------
				   PART II
				     OF
     
     A LOCAL HIDDEN VARIABLES MODEL THAT EXPLOITS DETECTOR INEFFICIENCY
	 WHICH EXACTLY REPRODUCES THE QUANTUM MECHANICAL PREDICTION
			FOR TWO PARTICLE CORRELATIONS
			     
			     
			     Douglas G. Danforth
				July 27, 1992
 
 

Aspect [2] defines a quantity E(a,b) to estimate P(a,b) using detector counts
R(a,b) as:
		 
		 R++(a,b) + R--(a,b) - R+-(a,b) - R-+(a,b)
	E(a,b) = -----------------------------------------	(II.1)
		 R++(a,b) + R--(a,b) + R+-(a,b) + R-+(a,b)


The corresponding theoretical expression is:

				   
                 /dv f(v) A(a,v)B(b,v)
	P(a,b) = ----------------------				(II.2)
	                   2     2
	         /du f(u) A(a,u)B(b,u)


which differs from Bell's expression by the denominator.  For perfect
detectors the square of A and B is 1 which coupled with the normalization of
the density, f,  leads to a denominator value of 1.  For imperfect detectors
there is a third state of nondetection, 0.  A and B, in this case, satisfy
	 
	 3	  3
	A  = A,  B  = B	       (imperfect detector condition)	(II.3)

which holds for all detector angles 'a' and 'b' and all hidden variable
values v.

The inclusion of the denominator expresses the conditionalization on the
distribution function f(v) to the set of points J where joint detection
occurs

	         2              2
	J = {v| A(a,v) = 1 AND B(b,v) = 1}.			(II.4)

The denomintor in (II.2) for imperfect detectors is no longer unity.  For
the crown model the denominator is a constant, j, equal to the area of joint
overlap of the two crowns disregarding the sign of the overlap.  This
overlap is simply the sum of the areas of the 8 scallops.

	              2     2	       pi/2   
	j = /dv f(v) A(a,v)B(b,v) = 8 /dx g(x)
				     0	      

	     pi/2						(II.5)
	j = /dx sin(2x) = 1/2 					
	   0

The numerator in equation (II.2) is calculated as

                   	         pi/2        a-b    
        /dv f(v) A(a,v)B(b,v) = 8/dx g(x) - 8/dx g(x)
                	       a-b          0

                   	         pi/2          a-b    
                              =  /dx sin(2x) - /dx sin(2x)
                	       a-b            0
				       
				       2	      2
                              = 1/2 cos(a-b) - 1/2 sin(a-b)

                              = 1/2 cos2(a-b)			(II.6)


(The factor of 1/2 was missing from equation (8) in the previous posting).

The theoretical correlation function becomes

                 /dv f(v) A(a,v)B(b,v)	  
	P(a,b) = ----------------------
	                j              


                 1/2 cos2(a-b)
	P(a,b) = ------------- = cos2(a-b), 			(II.7)
	             1/2


as before.

I trust this clarifies the previous posting.

Newsgroups: sci.physics
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: "What's New" July-24-1992
Organization: University of Virginia
Distribution: na
Date: Wed, 29 Jul 1992 18:27:55 GMT

In article <25024@dog.ee.lbl.gov> sichase@csa2.lbl.gov writes:
>In article <1992Jul29.042544.7010@murdoch.acc.Virginia.EDU>, crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes...
>> 
>>     How exactly does one quantify 'the amount of new engineering'
>>     in a project comprised of components that have never been built
>>     before?   With this in mind, how do you state that there is
>>     more 'new engineering' in SSF vs. SSC.  Both sets of designers
>>     have attempted to keep the technological risks of their 
>>     prospective toys down.
>> 
>
>At least for the SSC, the design emphasized known technology specifically
>so as to downplay the need to depend on "new engineering." That was crucial
>to insuring timely construction.  Surely as an engineer you know that it
>is always possible to choose from a wide variety of materials and techiques,
>some of which have proven track records, and others, though they might
>promise increased performance, pose the risk of cost and time overruns which
>might defeat the purpose of the project.
>
>Although I don't know exactly how to "quantify" these things, I certainly 
>know how to judge two designs side by side to decide which one seems a 
>safer design choice.

     The same has been done (several times) in the design of SSF.

     This 'new engineering' thread is probably not a fruitful thread
     to pursue since a 'safer design choice' is not well-defined
     in this context.  I 'know' that a space station can be put
     in orbit that will satisfy the performance objectives.  I do not
     'know' that such can be done for the SSC.  Which is 'safer'
     in this context.

                                  dale bass
--
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Aristotle and the Modern Physicist
Date: 23 Jul 92 15:41:45 GMT
Article-I.D.: husc8.mcirvin.711906105

matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:

>[The scene: Aristotle is accidentally translated in time to the late
>20th century, while working on the Physics. He asks a Modern Physicist
>to help him to catch up with things.]

[After the Modern Physicist convinces Aristotle that inertia is
not due to interaction with an "inerton"... Aristotle studies
gravity, and greatly admires Einstein's extension of Newton.]

>A: Well, Einstein has explained gravity by transferring it from the
>domain of the Second Law to that of the First. A free particle moves
>along a "straight line", where this expression is taken to mean a
>geodesic in the appropriate spacetime. Thus we can say, eg, that the
>Earth moves around the Sun, not, as Newton mistakenly thought, because
>the Sun and the Earth interact, but rather because they DO NOT interact!
>If they interacted, the motion would not be geodesic. Magnificent!
>MP: No! No! You have it all wrong! The Earth moves around the Sun
>because there is some interaction [let us call it "gravity"] mediated by
>some hitherto undetected particle which I hereby dub the "graviton",
>with a spin that may readily be calculated........
>Moral: It takes more than an Einstein to abolish the fantasy of the
>"gravitational interaction".

Very funny, but I think you're being a bit harsh on the Modern
Physicist here.  Nobody expects quantum gravity to be a theory
in which all gravitational interactions can be calculated via,
say, Feynman diagrams involving the exchange of virtual gravitons.
What is hoped is just that the dynamics of geometry can be
made into a quantum theory.  *Real* gravitons would be quite
present in such a case: gravitational radiation, waves in
the metric, would occur only in discrete quanta.

Even if it were possible to turn quantum gravity into something
accessible via perturbation theory, one must realize that
physicists are being rather metaphorical when they speak of
virtual particles caroming off each other to mediate forces.
The pictures are largely a computational and visualization aid
for what is really the interplay of fields, which happen
to consist of quantum operators.

Granted that things under the influence of gravity travel
along geodesics, you can't deny that the metric affects where
they end up going.  In that sense there is an interaction
with the "gravitational field," defined as fluctuations in
the geometry.

And if Aristotle said to the Modern Physicist that the 
amount of rest mass belonging to the particle was due
to an "inerton," the Modern Physicist would probably
agree with him!
 
-- 
Matt McIrvin   mcirvin@husc.harvard.edu   Long live short .sigs
From: mjb@acsu.buffalo.edu (Matthew J. Bernhardt)
Newsgroups: sci.physics
Subject: Re: Blue Sky
Date: 22 Jul 92 00:54:47 GMT
Organization: UB

andrew@rentec.com (Andrew Mullhaupt) writes:

>Why is the sky blue?

	I'll bite.  The composition of the Earth's atmosphere (four fifths
nitrogen, one fifth oxygen) is such that incoming light is refracted to make
the sky appear blue.
	On Mars, the atmosphere is different, and acts to produce a pink
sky.

	No doubt the quantum mechanical justification of this phenomenon
is forthcoming...
-- 
Matt Bernhardt
University of Buffalo             THIS SPACE FOR RENT.
mjb@acsu.buffalo.edu
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: Chaos
Date: 21 Jul 92 19:06:12 GMT
Organization: University of Virginia

In article <1992Jul21.174653.28962@ucsu.Colorado.EDU> hatay@spot.Colorado.EDU (Ferhat F. Hatay) writes:
>Talking about the low-dimensional system: Can I bring the 
>work of Glauser and his coworkers to your attention?
>In this line of work, they use the Proper Orthogonal
>Decomposition idea of Lumley to turbulent flows. 
>POD modes are obtained either experimentally or numerically. 
>Analysis reveal that it is possible to do a reconstruction
>of the flow field using a finite number of POD modes. 
>As this can be labelled as the "coherency" (here goes 
>another vague term) in the flow field, dynamical 
>evolution of these finite number of modes can be 
>written an played with. 
>
>Does anyone think this kind of work might provide a 
>link between chaos and turbulence (in fluids) ?

     Lumley and his students have been trying stuff along these
     lines for over 25 years (good early ref is Lumley's 'Stochastic
     Tools in Turbulence').  More recently there have been
     several papers in Phys Flu (88 or 89 with Chambers as one
     of the authors) including a review of turblence theory in general
     by Lumley (Phys. Flu. A 4:203 (1992)).   The work involves a
     Karhunen-Loeve transform to maximize the energy a finite number
     of modes of a truncated expansion.  The interesting thing
     is that in the Fourier framework, the KL expansion is the
     'best' one can do with a finite number of modes.

     Also, there have been a number of efforts by Lumley's students
     (such as Nadine Aubrey) to select 'coherent structures' from
     computed and experimental flow fields.  The unfortunate problems
     are: 1) it is very difficult to 'select' them in a rational
     manner to be sure that you are not inventing them, 2) even if
     they exist is is difficult to assess their dynamical importance
     in the flow.

                                  dale bass

--
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Aristotle and the Modern Physicist
Date: 24 Jul 92 16:22:56 GMT
Article-I.D.: husc8.mcirvin.711994976

matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:

>I fear...correct me if I am mistaken... that when you say that
>the "metric affects where they are going" you are thinking of the metric
>tensor as a thing that lives on Minkowski space: the particle would
>really like to follow the Minkowski geodesics, but the metric compels it
>to go elsewhere.

Not really... my point is that the metric in GR isn't a fixed thing; it
depends on the distribution of masses, stresses, etc., and that where
my test particle eventually ends up depends on that distribution of
masses etcetera, and that the effect is due to the metric.  Whether
you call that an interaction or not is immaterial... we obviously
agree on what's going on.

Now, a remarkable thing is that you *can* start by thinking of the
metric as a thing living in Minkowski space and trying to construct
a workable tensor field theory; you eventually end up with GR.  This
is covered somewhere in Misner, Thorne, and Wheeler.  But the
"underlying Minkowski metric" is obviously artificial, not a thing
essential to the theory. 

>Would you say that the Minkowski metric "interacts"
>with free particles in Minkowski space and "forces" them to move along
>straight lines ["inertons"!]? No? Well, if you do not wish to say it of
>Minkowski space, then don't say it of any other spacetime. "Gravity" was
>all a mistake, resulting from our ignorance of spacetime curvature. How
>does one quantize a mistake?

One doesn't quantize a mistake; one quantizes spacetime geometry.
I don't know much about quantum gravity, but I do know that it
*doesn't* assume gravity to be an effect independent of geometry,
living on Minkowski spacetime.  You *can* go a certain distance in
this way, defining the field to be perturbations of the metric,
expressed as a tensor; using the general relativity Lagrangian,
with nonlinearities treated as self-interaction terms; and trying
to construct a perturbation theory.  However, you immediately
run into extreme trouble from the necessity of renormalizing an
infinity of nonrenormalizable interaction terms, and the whole
program falls in.  Therefore, this approach is *not* considered
fruitful. 

I think that the efforts in quantum gravity currently in progress
have less to do with gravitons than with trying to define a 
functional integral over different geometric configurations of
spacetime, with the scalar curvature giving the action.  This is
essentially the application of Feynman's path-integral technique
to the dynamics of geometry described by general relativity.  All
kinds of problems occur, but they are *not* the result of ignoring
the fact that an object in free fall is simply following a
geodesic. 

If you don't like the world "gravity," you can use MTW's term
and talk about "quantum geometrodynamics."
 
-- 
Matt McIrvin   mcirvin@husc.harvard.edu   Long live short .sigs
Newsgroups: sci.physics,sci.math
From: jbaez@nevanlinna.mit.edu (John C. Baez)
Subject: Re: Chaos
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Tue, 21 Jul 92 21:19:21 GMT

In article <1992Jul20.153122.29180@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
>In article <1076@kepler1.rentec.com> andrew@rentec.com (Andrew Mullhaupt) writes:
>>OK but there is still a universal attractor for the N-S equations as
>>rigorously proved by Foias et. al. The dimension is about 500 (as one
>>expects from various other estimates). Renormalization is not necessary
>>for an attractor, although the Orszag-Yahot theory is essentially a
>>renormalization theory. The Foias stuff can be found in the book by
>>Foias and Constantine, but I think the attractor theorems came after
>>his book with Roger Temam, although my memory may be playing tricks.

>     Is this the 'universal attractor' for 2-D NS with periodic and
>     dirichlet BC's?  

Could someone elaborate a bit more on this idea and what precisely was
proved?  I find it rather odd.  I seem to recall that the 2-D nonlinear
Schrodinger equation with cubic nonlinearity is completely integrable
(let's take periodic boundary conditions, say).  What sort of
nonlinearities does Foias consider, and what is a "universal attractor"?