HDTenEightyP/NetNews huggingface dataset:
From: ramsay@unixg.ubc.ca (Keith Ramsay)
Subject: Re: Simple observation about Quantum Kitty Cats
Organization: University of British Columbia, Vancouver, B.C., Canada
Date: Fri, 2 Oct 1992 01:52:48 GMT

In article <298@mtnmath.UUCP> paul@mtnmath.UUCP (Paul Budnik) writes:
[...]
>Interpretations exist for quantum mechanics because the theory is not
>formalizable. One cannot define a model for a quantum mechanical system
>in ZFC. That is the standard criteria for whether a mathematical model
>has a rigorous definition. If that were possible there would be no
>ambiguitys about what quantum mechanics means in a mathematical sense
>and there would be no need for interpretations. 

I think this is somewhat misleading. I don't see what ZFC particularly
has to do with it, nor "formalizability". The ambiguities in the
interpretation lie mainly in what the terms, as formalized (which can
be done in a variety of ways), should be taken to mean. It is not so
much a mathematical or theoretical problem as a philosophical problem.

>It is not simply a matter of being extremely difficult to define such
>a model. It would take some major change to ZFC to allow one to rigorously
>define a random sequence. 

Are you saying that probabilistic theories in physics are inherently
dubious?

It is not clear that there even exists such a notion of "random
sequence" as you seem to think would be required. (There are, of
course, definitions of "random sequence", just not of the sort meant
in this context.) People can perfectly well formalize probability
theory, however.

Probabilistic models, on one interpretation, tell us how thoroughly to
expect certain events to occur, how much confidence to place in events
occurring.  It is not clear that one ought somehow to be able to
convert such a theory into one which gives a black-and-white criterion
for when a sequence of events does or does not conform to
expectations- for whether the sequence is "a random sequence" or
isn't. Confirmation is a matter of degrees.

>                    A change that I do not think any mathematicians
>foresee happening. 

Yet I don't think it has persuaded any of us to abandon probabilistic
models.

>                    It would also be difficult to rigorously define
>what happens when an observation is made and make this consistent with
>a rigorous definition of special relativity.

Perhaps so. My impression is that something in this direction has been
done, however, in specifying conditions which have to hold between the
operators associated with observables, observed at a space-like
separation, to prevent observation from being usable as an FTL
communications channel.

Keith Ramsay
ramsay@unixg.ubc.ca
Newsgroups: sci.physics
From: isupstud@bnr.ca (Wayne Hutton)
Subject: Re: Can you figure this joke out?
Reply-To: isupstud@bnr.ca (Wayne Hutton)
Organization: Bell-Northern Research Ltd.
Distribution: na
Date: Tue, 6 Oct 1992 14:35:06 GMT



>> The integral of 'e' to the 'x' is a function of both 'u' and 'n'.



>I can't imagine that too many people subscribing to this newsgroup
>wouldn't get the joke.  Come on ...
>                        x
>	[Integral sign] e   dx      is        F (u,n)
>
>of course the joke looses something when you show the integral properly
                    ^^^^^^

	** The sign of a true physics major  (loses?) **


>by including the "dx".


	I'm sorry if I bored you with my joke, I was just posting it
as a brief humor break from all these technical letters being posted.

ps- Try to laugh a little - it helps to keep the stress level down.
From: danforth@riacs.edu (Douglas G. Danforth)
Subject: Probability courses (was Re: Schrodingers Dog)
Keywords: Cats , Quantum Merchanics, Cruelty to Animals
Organization: RIACS, NASA Ames Research Center
Date: Mon, 5 Oct 92 00:21:02 GMT

In <1992Sep30.135833.202931@uctvax.uct.ac.za> naturman@uctvax.uct.ac.za writes:


>One of the reasons I gave up physics to become a mathematician was that I was
>sick and tired of physicists who had no understanding of basic probability
>theory but who continually bullshited about QM.

This gives me an opportunity to ask the net a question I have long
wished to ask:

How many of you (with BS, MS, or PhD in physics) were required to take
a course in probability theory given by the math or statistics departments
in your universities?  A course in statistical mechanics does NOT count.

Specifically the words "random variable" and "measure space" must have
been included.

I ask this simply because I had to leave the field of physics before I
was exposed to the true beauty of probability theory.  Neither Stanford's
undergraduate degree program nor the U. of Maryland's graduate program
required a course in probability theory.  This is truely remarkable
since Stanford's statistics department is about 100 feet from the
physics building!

I'm truely curious.  How many of your departments require courses in
probability theory?

Douglas Danforth

Newsgroups: sci.physics
From: phfrom@nyx.uni-konstanz.de (Hartmut Frommert)
Subject: Re: Speed of propagation of gravity (was Re: Spin)
Organization: Dept. of Physics, University of Constance
Date: Tue, 29 Sep 1992 15:52:48 GMT

Hoping to clear and not add some confusion :-)

In Newtonian physics, gravity (i.e. the scalar gravitational potential field)
is non-dynamic, since it has a time-INdependent field equation (the Poisson 
equation). Therefore, at each moment of time, this eq must be fulfilled at
arbitrary large distance, i.e. if 
  r_i(t)    is the position (at the moment t) of the i-th point particle 
(with [active] gravitational mass m_i) in a model configuration, then the
Newtonian grav'l potential U(r,t) at some position r and time t is given by

  U(r,t) = U(r,{ r_i(t) }) 

                  G * m_i
       [ = SUM  ------------ ]
            i    |r-r_i(t)|

(which you all know). If at least one test particle changes its position, 
this simultaneously changes U(r,t) in the whole spacetime, so that 
"Newtonian gravity in Galilean spacetime" has infinite propagation velocity.

On the other hand, Einsteinian metric gravity (curvature) in GR propagates 
with the velocity of light c (also wellknown, or readable in most GR books). 
Moreover, if you take a look at special-relativistic, i.e. Lorentz invariant
theories of gravity (scalar, vector, or tensor, see, e.g. MTW chapter 7;
ok, they are probably all not present in nature :-)),
then gravity gets a finite velocity ("retarded" potential), usually c [iff
"gravitons" are massless, but c_g < c iff "gravity" is mediated by massive 
particles]. Thus one can make Newtonian gravity Lorentz invariant (just 
replace the Laplace operator by the d'Alembertian and the mass density by 
the trace of the energy momentum tensor in the Poisson eq) -- this
"Newtonian gravity in Minkowsky spacetime" will then propagate with c_g == c.
--
 Hartmut Frommert                 <phfrom@nyx.uni-konstanz.de>
 Dept of Physics, Univ of Constance, P.O.Box 55 60, D-W-7750 Konstanz, Germany
                                           -- Eat whale killers, not whales --
Newsgroups: sci.physics
From: taylors@hubcap.clemson.edu (C. Taylor Sutherland III)
Subject: Re: Grad School
Organization: Clemson University
Date: Sun, 13 Sep 1992 19:05:39 GMT

cannon@scs.unt.edu (Dustin Cannon (Lab 3460)) writes:


>	I was wondering if anyone could suggest a good grad school for me.  
>My emphasis is theoretical physics, I would like a school strong on 
>that.  I'm a senior at the University of North Texas, with a physics major 
>and math minor.  I have a 4.0 in my major and a 3.7 cumulative.  I have not 
                           ^^^
DIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIEDIE :P

>taken my GRE yet, so I can't give you those scores.
>	I would prefer a place where I'm not simply given a project by a 
>professor and he says "See ya finals week."
>	As far as money goes, I'm going to need TAships, TFships, grants, or 
>scholarships of some sort.
>	Well, those are the facts.  Any suggestions? Thanks in advance for 
>any advice.
>_________________________________________________________________
>Dustin W. Cannon      "Just because some of us can read and write
>University of          and do a little math, that doesn't mean we
>North Texas            deserve to conquer the universe."
>                                                -Kurt Vonnegut

-- 
	I've heard a good .sig can let you meet people....
	Anybody got any good ideas for one?
The Fly Boy  <| E-MAIL:  taylors@hubcap.clemson.edu |>
+--<| My life is a math question with one equation and 42 unknowns. |>--+
Newsgroups: sci.physics
From: tolman%asylum.cs.utah.edu@cs.utah.edu (Kenneth Tolman)
Subject: Re: Thermo question for you
Date: 2 Oct 92 16:42:28 MDT
Organization: University of Utah, CompSci Dept

Thanks for your reply!

>I don't like the idea of refering to the "entropy of a microstate" very much.

why not?

>I am most distressed by the idea of applying the entropy
>concept to a two-particle system. Why on Earth would anyone ever want to do
>that?

To understand thermodynamics better.  Thanks!

>Surely no physical result can be inferred from consideration of such a
>system. Are we discussing physics here? 

What are you discussing?  I am discussing physics.  Why can no physical
result be inferred from consideration of such a system?  Au contriar!
Many physical results can be discovered from studying such a system in
detail.  Study it if you will, very carefully, and you will see what I
am rumbling about... great secrets lie in simple places, perhaps.
From: ynecgan@cid.aes.doe.CA (Greg Neill)
Newsgroups: sci.physics
Subject: Re: Local expansion
Keywords: expansion, Hubble, gravity
Date: 29 Sep 92 13:51:49 GMT
Organization: Environment Canada (CID), Dorval, QC

In article <80536@ut-emx.uucp> joe@astro.as.utexas.edu (Joe Wang) writes:
>In article <1992Sep23.143830.25927@cid.aes.doe.CA> ynecgan@cid.aes.doe.CA (Greg Neill) writes:
>>I have repeatedly come across
>>statements similar to: "...the general expansion of the universe does
>>not affect galaxy structure or clusters, since they are held together
>>too firmly by gravitational forces."  Now, what the heck does this mean?
>>Is space not expanding uniformly at all scales?  
>
>Nope.
>
>The calculations that demonstrate that the universe should expand a
>uniform rate ASSUME that you have a universe whose density is uniform.
>Now at large scales, this is a pretty good assmuption.  If you look
>at the universe as a whole, it looks and acts a lot like a uniform
>fluid, just like a air looks and acts a lot like a uniform fluid if
>you don't look closely enough to see atoms.
>
>At small scales, however, the universe is not uniform, and so you have
>to throw any calculations assume that it is out the window.  


So at very small scales, in the viscinity of matter condensations (like
a cluster, star, or solar system) space does not expand.  Where does one
draw the periphery about a clump of matter such that on one side of the 
dividing line space is expanding, and on the other side it is not?  Can 
we get work out of a system spanning such a boundary, effectively tapping
energy directly from the Big Bang itself?

Looks like the universe is "blowing bubbles", since we would expect the
large voids to expand while "connected" features like Great Walls would
not...although I suppose the Walls would eventually be stretched mighty
thin.  This presumes, of course, that the expansion continues
indefinitely.  A closed or flat universe would demonstrate some limiting
overall density.
--
From: naturman@uctvax.uct.ac.za
Newsgroups: sci.physics
Subject: Schrodingers Dog
Keywords: Cats , Quantum Merchanics, Cruelty to Animals
Date: 30 Sep 92 15:58:33 GMT
Article-I.D.: uctvax.1992Sep30.135833.202931
Organization: University of Cape Town

It looks like I've been missing some posts on kitty cats. I would like to point
out the following:

1) Kitty cats are tangible objects.
2) Wavefunctions are mathematical functions defined over a region of space and
   time. They are abstract.

Wavefunctions don't pass through slits. They are defined over a region which 
includes the slits. The fact that they are nonzero at the slits reflects the 
fact that if you don't look you don't know which slit the particle goes
through. This is equivalent to not knowing if the kitty is dead or alive.

Physicists just don't seem to understand that probability has got to do with
knowledge. Probabilities are not absolute but depend on the observer. If we
put Schrodingers doggy in the box with a gas mask then the "alive/dead
wavefunction" collapses for him when he sees the kitty kick the bucket or not,
but it does not collapse for Schrodinger.

One of the reasons I gave up physics to become a mathematician was that I was
sick and tired of physicists who had no understanding of basic probability
theory but who continually bullshited about QM.

Lets face it, the argument is not about kitty cats. The real gripe is that some
people are worried about not having free will and they think that their nonsense
interpretations of QM will restore their lost free will.

Meow!
 
*****************************************************************************
* 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: Richard.Mathews@West.Sun.COM (Richard M. Mathews)
Newsgroups: sci.physics
Subject: Re: Local expansion
Keywords: expansion, Hubble, gravity
Date: 29 Sep 92 00:23:28 GMT
Organization: Sunsoft Inc., Los Angeles, CA.
NNTP-Posting-Host: astro
Originator: richard@astro.West.Sun.COM

joe@astro.as.utexas.edu (Joe Wang) writes:

>The calculations that demonstrate that the universe should expand a
>uniform rate ASSUME that you have a universe whose density is uniform.
>Now at large scales, this is a pretty good assmuption.  If you look
>at the universe as a whole, it looks and acts a lot like a uniform
>fluid, just like a air looks and acts a lot like a uniform fluid if
>you don't look closely enough to see atoms.

Agreed.  A good way to see this is with the picture on page 739 of Misner,
Thorne, and Wheeler.  You don't need to understand MTW to understand
this picture.  Replace the usual universe-is-a-balloon picture with
one where the universe is a ball with spikes coming out of it.  Each
spike corresponds to a gravitational well of a mass concentration.  Away
from the concentrations, the universe is octahedral or dodecahedral or
whatever, depending on the number of mass concentrations you use.  The
key is that the universe is essentially flat in all the gaps.  It is
even locally flat along the edges (just as a cylinder is locally flat
everywhere).  All the curvature is concentrated at the spikes.  As the
balloon expands, all of the expansion occurs between the spikes.  Within
each gravitational well, you can ignore the expansion and just consider
the gravitational effects of the local masses.  Out near the edges of the
wells, you have to consider the universe as a whole.  Now to quote from
MTW,
	Surrounding each center of mass, the geometry is and
	remains the Schwazschild geometry (until eventually the
	black holes come so close together that they coalesce).
	The situation inside each cell is therefore static.
	Moreover, the interface between cell and cell is defined
	in imagination by a sprinkling of test particles so
	light that they have no influence on the geometry or
	its dynamics.  The matchup between the geometry in
	one cell and the next is smooth ("tangency between two
	geodesics").  There is nothing abnormal whatsoever in
	the space-time on or near the interface.
The point is that while we can't associate the expansion with anything
happening in any particular "strange" place, the effect is that things
act based purely on local effects when deep within the gravitational
wells, and the wells are flying apart.

     Richard M. Mathews			D efend
					 E stonian-Latvian-Lithuanian
Richard.Mathews@West.Sun.COM		  I ndependence
From: rl@socrates.ucsf.edu (Robert Langridge)
Newsgroups: sci.physics
Subject: Rosalind Franklin (was: Meitner and Hahn)
Date: 28 Sep 92 20:27:38 GMT
Organization: UCSF Computer Graphics Lab

jac@ds8.scri.fsu.edu (Jim Carr) writes:
[...discussion of Hahn/Meitner...]
>
>Not nearly as clear-cut a case as in the DNA story, where Rosalind (?) 
>Franklin actually made the measurements and the correct interpretation 
>of the measurements.  The excuse there is that she had died by the 
>time the award was made, and was thus not eligible, but begs the 
>question of why others who did not make the real discovery were 
>considered eligible! 

There is certainly a case to be made that Franklin, if she had lived,
should have shared the Nobel Prize with Crick, Watson and Wilkins.
This would have given the Nobel Committee serious problems since the 
award is restricted to no more than three individuals.  As jac says,
no award is made posthumously, but to say that the three who got the
award did not make the real discovery is utter nonsense.  As in much of
science, no one person deserves the credit.

Robert Langridge			Phone: +1 415 476-2630, -1540, -5128
Computer Graphics Laboratory		               FAX: +1 415 476-0688 
926 Medical Sciences
University of California	                    E-Mail: rl@cgl.ucsf.edu
San Francisco  CA  94143-0446 
Newsgroups: sci.physics
From: rmz@ifi.uio.no (Bj|rn Remseth)
Subject: Feynmann diagrams
Organization: Institute of Informatics, University of Oslo
Date: Fri, 2 Oct 1992 15:42:18 GMT
Originator: rmz@maud.ifi.uio.no


Are there any computer programs  for drawing and manipulating Feynmann
diagrams?


--
                                                    (Rmz)

Bj\o rn Remseth   !Institutt for Informatikk    !Net:      rmz@ifi.uio.no
Phone: +472 453466!Universitetet i Oslo, Norway !NeXTmail: rmz@neste.ifi.uio.no
Newsgroups: sci.physics
From: choy@skorpio.usask.ca (I am a terminator.)
Subject: Re: Why do physicists make preposterous predictions?
Organization: University of Saskatchewan, Saskatoon, Canada
Date: Mon, 5 Oct 1992 22:03:08 GMT

In article <Bv458q.1E1@news.cso.uiuc.edu>, jjt@uihepa.hep.uiuc.edu writes:
|> paul@mtnmath.UUCP (Paul Budnik) writes:
|> 
|> > Look up at the sky this evening. Photons from stars and galaxies
|> > as distant as millions and even billions of light years will strike
|> > your eye. Many of these will, according to quantum mechanics, be in
|> > a singlet state, paired with another photon. These two were created
|> > in a single decay event and have been journeying through space in 
|> > opposite directions for eons. Yet quantum mechanics maintains that
|> > there are still connected.

Can anyone tell me the characteristics of this connection? If I can
bend the path of one of these photons, what happens to its buddy? Have
earthly experiments been done to observe the couples?

Henry Choy
choy@cs.usask.ca
From: jrtz@stat1.bst.rochester.edu (John Ritz)
Newsgroups: sci.physics
Subject: Examples of Statistical Experim. Designs ?? Anyone ?
Date: 6 Oct 92 03:18:24 GMT
Organization: University of Rochester - Rochester, New York


 

	Examples of Statistical Experim. Designs ?? Anyone ?

	
	I would be interested in seeing some explicit examples 
        of people using Statistical Experimental Designs : 
        One - and Two - way ANOVA , Randomized Block , 
        Mixed effets , Latin Squares , Factorial etc. , 
        in this area of science. If you have any , please 
        email me at jrtz@stat1.bst.rochester.edu . You 
        can give a reference to a Journaltogether with 
        volume , no. and pagenr. ( e.g. Technometrics , vol.11 ,     
        no.1 .. ) .

        Thx !
From: bafta@cats.ucsc.edu (Shari L Brooks)
Newsgroups: sci.physics
Subject: Re: Mattel Protest
Date: 7 Oct 1992 02:37:13 GMT
Organization: University of California - Santa Cruz, CA, USA
NNTP-Posting-Host: am.ucsc.edu
Summary: they *want* girls to not be good in math


In article <1992Oct5.165327.16115@murdoch.acc.Virginia.EDU> 
crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:

>In article <BvnJnx.52y@helios.physics.utoronto.ca> 
>dooley@helios.physics.utoronto.ca (Kevin Dooley) writes:

>>This is especially true with girls who are repeatedly told that
>>they should not be good at math or science courses because their brains
>>don't work that way.  Nothing could be farther from the truth.  Let's
>>not permit marketing idiots to create yet another generation of math
>>anxiety and women who believe that they are somehow inferior!

>    Most kids who do badly in Math do so because it *is* hard, just
>    as English is hard, Chemistry is hard, Social Studies is hard.
>    Also, I hardly think that most girls are told that they should not
>    be good at math.  If you want to change math anxiety,

While I agree with the first statement (though I would have phrased it another 
way) I must differ with the second.  Throughout high school I constantly had
to put up with teachers giving me *shit* because I consistently outperformed
the males in my math and science classes.  In one class I got a full grade
lower than I deserved and when I asked why I was told, because I was a girl.
[This was a math class, BTW]  In a biology class, I got the highest score in
the class and my friend David had to be publicly humiliated by the teacher
because he let a *girl* beat his score.  How could he do such a thing? -- the
teacher asked him in class.

I also vaguely remember taking standardized tests on math & English skills,
[California requires that these be administered every other year, or did when
I was in school] and being told ahead of time that it was OK to do poorly
on the math parts cuz girls usually didn't do as well as the boys.

So, I think that society does promulgate the stereotype, discouraging women
to get involved in the sciences by both subtle and overt "math is not for
you" messages to girls.
    
I don't think it's an organized plot or anything though...

[sorry about the language.  not sorry enough to take it out]

-- 
If you blow fire against the wind, take care to not get the smoke in your eyes.
      Big & Growly Dragon-monster        |       bafta@cats.ucsc.edu
     ------> shari brooks <-------       |       bafta@ucscb.ucsc.edu
                             All opinions are my own.
From: mbk@hamilton (Matt Kennel)
Newsgroups: sci.physics
Subject: What is the Speed of Exclusion
Date: 1 Oct 1992 20:47:08 GMT
Organization: Institute For Nonlinear Science, UCSD
NNTP-Posting-Host: hamilton.ucsd.edu
X-Newsreader: Tin 1.1 PL3

phfrom@nyx.uni-konstanz.de (Hartmut Frommert) writes:
: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:
: 
: >I hope that the eventual entry will discuss what happens when the
: >gravitational waves are propagating in a background which is not
: >approximately flat. Does "gravity" propagate at the speed of light near
: >a black hole?
: 
: To my knowledge, Einsteinian gravity waves always propagate at the same
: velocity as "classical" light, i.e. mass- and structureless point particles
: [which do not exist] along null geodesics.

What's the speed of propagation of the Pauli exclusion "force"?

I.e. you have a macroscopic degenerate system.  All of a sudden one particle
decays into other stuff (you measure the decay products and so localize the
position of the ex-particle) and leaves a state free.  How long is it before
the other side notices?

Would this be a physical effect of wavefunction "collapse"?

:  Hartmut Frommert                 <phfrom@nyx.uni-konstanz.de>
:  Dept of Physics, Univ of Constance, P.O.Box 55 60, D-W-7750 Konstanz, Germany
:                                            -- Eat whale killers, not whales --

--
-Matt Kennel  		mbk@inls1.ucsd.edu
-Institute for Nonlinear Science, University of California, San Diego
-*** AD: Archive for nonlinear dynamics papers & programs: FTP to
-***     lyapunov.ucsd.edu, username "anonymous".