HDTenEightyP/NetNews huggingface dataset:
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Defining Photons
Date: 31 Jul 92 19:04:38 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 <15ab4nINNfnk@agate.berkeley.edu>, aephraim@physics.Berkeley.EDU (Aephraim M. Steinberg) writes...
> 
>Well, actually photons behave classically when there are a lot of them 
>around, AND they are in a coherent state (a particular kind of coherent
>superposition of different number-states of photons which most closely
>resembles a classical field, and yields the familiar Poisson counting
>statistics one expects from independent random processes, just to define
>the jargon in advance).  Recent work on squeezing is based entirely on
>the concept that you can have many photons around but in a different
>kind of state (you guessed it, a squeezed one, the simplest example of
>which is a number state, e.g., exactly 500 quadrillion photons in a
>cavity), and such a state will NOT act classically.  Most of the talk

OK.  And by analogy, it is possible to put an electron into a high
energy state an have it still behave quantum mechanicanically by 
carefully preparing the state.  But this is really beside the point, 
which was "which property of the photon is responsible for its
wavelike properties in the classical limit."  I think that we have
settled that one definitively in favor of "spin" rather than "mass".

P.S.  Your quote is better than mine.  :'(  I guess it's time for 
a new quote.

-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
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Twins Paradox Resolved
Date: 23 Jul 92 00:35:20 GMT
Article-I.D.: husc8.mcirvin.711851720

gast@next.ben-fh.tuwien.ac.at (Gast) writes:

>In article <1992Jul22.130948.18912@cs.ucf.edu> clarke@acme.ucf.edu (Thomas  
>Clarke) writes:
>> In article <BrrztE.J4u@well.sf.ca.us> metares@well.sf.ca.us (Tom Van  
>Flandern)  
>> writes:
>> >     For those unfamiliar with SR, SR implies that events synchronized  
>in one
>> >frame will not be synchronized (= simultaneous) in a relatively moving  
>frame.
>> 
>> Not true.

>It is true. Two events that happen simultaniously in one system don't in a  
>system which is moved in respect to the former system.

...at least not if they happened in different *places.*

-- 
Matt McIrvin   mcirvin@husc.harvard.edu   Long live short .sigs
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Defining Photons
Date: 27 Jul 92 17:42:56 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa3.lbl.gov
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Keywords: Relating photons E=MC^2 criticism
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In article <26JUL199218561022@zeus.tamu.edu>, dwr2560@zeus.tamu.edu (RING, DAVID WAYNE) writes...

>Hmmm... I disagree with you both :-)
> 
>I think anything with a charge will appear as a particle in the classical
>limit, whether boson or fermion. Like a W in a cloud chamber. And anything
>which interacts as weakly as a neutrino would behave like a wave.

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.

Meanwhile, if you happened to have a low energy neutrino in a bottle (bound
in some kind of neutrino atom or something) and wanted to study its classical 
behavior, you would be able to do it by exciting it to a sufficiently high
energy level.  Thus it is a particle in the classical limit, not a wave.

>Anyway, I wonder if our non-scientist friend knows that electrons are really
>massless, and that they only _look_ massive because of thier interaction
>with the higgs.

Even in the Higgs model the mass of the electron is not entirely from 
the Higgs-electron interaction, is it?  Up to a few percent of the mass
still comes from radiative effects (depending on what cutoff mass you use
when you renormalize).  And (as Matt Austern is always pointing out every time
I mention Higgses, the total body of evidence for the Higgs is so slim and 
indirect that, IMHO, it would not be fair to take potshots at an outsider 
for not knowing about them, yet.

-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,alt.fan.dale-bass
From: gsh7w@fermi.clas.Virginia.EDU (Greg Hennessy)
Subject: Re: Gyromagnetic ratio of the proton
Followup-To: alt.fan.dale-bass
Organization: University of Virginia
Distribution: na
Date: Tue, 28 Jul 1992 00:39:49 GMT

In article <1992Jul27.235147.29265@murdoch.acc.Virginia.EDU>
crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes: 
#    I'm not using electrons either since the they were giving me
#    a jolt every time I touched the keyboard.

That could be a problem Dale. That is a lot of cola to drink. All that
caffine would give me the shivers.

Followups to alt.fan.dale-bass. :^)

--
-Greg Hennessy, University of Virginia
 USPS Mail:     Astronomy Department, Charlottesville, VA 22903-2475 USA
 Internet:      gsh7w@virginia.edu  
 UUCP:		...!uunet!virginia!gsh7w
Xref: sparky sci.physics:11270 sci.astro:8188
From: billn@hpcvaac.cv.hp.com (bill nelson)
Newsgroups: sci.physics,sci.astro
Subject: Re: Structure of Time
Date: 21 Jul 92 18:09:39 GMT
Article-I.D.: hpcvaac.1992Jul21.180939.12582
Distribution: sci
Organization: Hewlett-Packard Company, Corvallis, Oregon USA

schumach@convex.com (Richard A. Schumacher) writes:
: These things have gone from amusing, to annoying, and are now pathetic
: and alarming. By hanging on his five-years-old daughter's every word
: and treating her as a prophet of revealed truth, Whatsisname is doing
: her an enormous disservice. She will be shocked and embittered when
: she enters the real world of school and is either ignored or ridiculed
: by her peers and by adults. She will be fortunate if she manages to
: recover from this and grow up without hating either the world, or
: herself and her bizarrely-opinioned father.

One of two things is occurring. Either it is a con - by the father. Note
that he has to 'interpret' everything. Or, it is random babble of a fantasy
world. If it is the second, then I doubt if this idiot is bright enough to
ask his daughter the same questions he asked her a month ago. He would find
out that the answers are different - thus made up.

: I suggest that we give him neither the encouragement of serious replies
: to these fantasies, nor the ego-inflating challenge of ridicule, and
: instead ignore him completely.

A suggestion I intend to follow in the future.

Bill
From: srobiner@pollux.usc.edu (Steven Robiner)
Newsgroups: sci.physics
Subject: Standing WAVES
Date: 31 Jul 1992 01:16:27 -0700
Organization: University of Southern California, Los Angeles, CA
Distribution: world
NNTP-Posting-Host: pollux.usc.edu


Is it possible for three point sources emiting multiple waves of
different amplitudes and frequencies to generate a wave
pattern such that the sum of all the waves at all points near them
will have a constant amplitude?  

In other words, can one make a standing wave without a boundry?  

How about with two point sources?

Or just one?


=steve=

Newsgroups: sci.physics
From: danforth@riacs.edu (Douglas G. Danforth)
Subject: Re: Quantum Philosophy
Organization: RIACS, NASA Ames Research Center
Distribution: world,local
Date: Tue, 28 Jul 92 05:56:48 GMT

In <1992Jul27.160555.3547@arizona.edu> wallin@hep4.physics.arizona.edu (Tripp Wallin) writes:


> I'm an undergraduate in physics and have been interested in the threads lately about
> quantum physics. The thing though that has interested me the most is the various 
> intereptations of quantum theory. If anybody could recommend some books on the level
> of someone who has only gone as far as the model of the one electron atom I would really
> appreciate it. I'm taking an advanced quantum class in the fall and would also appreciate
> any recommendations for literature on the various intereptations at a higher level for 
> reading later on when I understand more. Thanks......  
> 
> Tripp Wallin
> Physics and Math undergraduate
> wallin@hep4.physics.arizona.edu

For a popular survey of issues in the philosophy of QM see:
Herbert, N. (1987).  Quantum Reality: Beyond the new physics.
Anchor Books, Garden City, New York.
From: andrew@rentec.com (Andrew Mullhaupt)
Newsgroups: sci.physics
Subject: Re: Blue hawks (was Blue Sky)
Date: 29 Jul 92 02:03:35 GMT
Organization: Renaissance Technologies Corp., Setauket, NY.

In article <1852@snap> paj@uk.co.gec-mrc (Paul Johnson) writes:

>Active illumination is not an option available to eagles.

Is this obvious? Bioluminesence is at least theoretically possible, and
the question is can the eagle generate a bright enough light. I can't
think of bioluminesence which is bright enough but is there any good
(i.e. theoretical) reason why they can't, (perhaps the color temperature
of the sky is higher than what room-temperature chemical reactions can
afford?)

Later,
Andrew Mullhaupt


Newsgroups: sci.physics
From: matt@physics2.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: Converting the masses
Date: 25 Jul 92 23:09:27
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
	<131163@lll-winken.LLNL.GOV> <1992Jul25.194550.1970@smsc.sony.com>
	<mcirvin.712113680@husc8>
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics2.berkeley.edu
In-reply-to: mcirvin@husc8.harvard.edu's message of 26 Jul 92 01:21:20 GMT

In article <mcirvin.712113680@husc8> mcirvin@husc8.harvard.edu (Mcirvin) writes:

> >	It's perfectly reasonable to talk about the mass of a
> >	macroscopic object.  The inertial mass of the object
> >	can be operationally defined in terms of the force
> >	that has to be applied to the object to produce a given
> >	rate of acceleration. 
> 
> In order to spare straw personnel further injury, let me state that
> the relativistic mass is obtained in this manner not from F = ma,
> but from F = dp/dt and p = mv.

I'm not at all sure that this is just a straw man: I believe that one
of the dangers of "relativistic mass" is that it leads people to
believe (mistakenly) that, using this as the "m" in equations of
Newtonian kinematics, these equations still remain valid
relativistically.

I think it is worth pointint out that many Newtonian equations have to
be modified in a relativistic context, and that, no matter what
definition of mass is used, equations like F=ma and E=(1/2)mv^2 are
only valid in the nonrelativistic regime.

Certainly the original poster suggested that he wanted to define mass
to be the constant of proportionality between force and acceleration,
not that he wanted it to be the constant of proportionality between
velocity and momentum.
--
Matthew Austern              I dreamt I was being followed by a roving band of
(510) 644-2618               of young Republicans, all wearing the same suit,
matt@physics.berkeley.edu    taunting me and shouting, "Politically correct
austern@theorm.lbl.gov       multiculturist scum!"... They were going to make
austern@lbl.bitnet	     me kiss Jesse Helms's picture when I woke up.
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: ZERO Nuclear impact (was: Is car pooling for real? etc)
Date: 25 Jul 92 18:01:06 GMT
Organization: University of Virginia

In article <1992Jul25.174836.4853@murdoch.acc.Virginia.EDU> gl8f@fermi.clas.Virginia.EDU (Greg Lindahl) writes:
>In article <1992Jul25.171557.4574@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
>
>>     Only two big problems.  1) It is not economical to do so,
>>     2)  Hydrogen go boom.
>
>Gee, Dale, I've seen both of these arguments addressed in recent
>Scientific American articles. I'm glad that you're an expert on the
>topic of hydrogen fuel, just like you're an expert on electrical power
>generation, but could you be bothered to support your arguments
>instead of just spouting them? Also, could you pick a better
>newsgroup? Thank you.

     Gee, Greg.  Once again you insist on implying that these
     objections have been *successfully* addressed rather than
     making the arguments yourself.  Is this simply laziness, or
     is it a realization that the counterarguments are weak? 

     I will repeat my last response to this type of obfuscation,
     to wit, 'implications and insinuations should not be mistaken
     for actually having made the argument.'

                                 dale bass

     P.S.  exploding hydrogen is a wonderful topic for this newsgroup.

--
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: matt@physics2.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: Converting the masses
Date: 25 Jul 92 18:49:56 GMT
	<131163@lll-winken.LLNL.GOV> <1992Jul25.194550.1970@smsc.sony.com>
Reply-To: matt@physics.berkeley.edu
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
NNTP-Posting-Host: physics2.berkeley.edu
In-reply-to: markc@smsc.sony.com's message of 25 Jul 92 19:45:50 GMT

In article <1992Jul25.194550.1970@smsc.sony.com> markc@smsc.sony.com (Mark Corscadden) writes:

> 	It's perfectly reasonable to talk about the mass of a
> 	macroscopic object.  The inertial mass of the object
> 	can be operationally defined in terms of the force
> 	that has to be applied to the object to produce a given
> 	rate of acceleration.  Methods exist which allow you to
> 	measure the mass of an object, so defined, with great
> 	precision.

This is true: in Newtonian mechanics, the acceleration of an object is
proportional to the force applied on it, and the constant of
proportionality is its mass.  That is,
		\vec{F} = m \vec{a}.  				    (1)
Sorry about the TeX notation, but it really is necessary for the point
I wish to make, which is that this is a vectorial equation: the 
acceleration really is proportional to the force, because it is in the
same direction.

This is a Newtonian equation, however, and it is not valid for a
relativistic object, no matter how "m" is defined.  For a relativistic
body, the force and the acceleration are *not* proportional.  The
acceleration is not in the same direction as the force.  In other
words: there is no such thing as an inertial mass in relativistic
physics, so there is no point in trying to define "mass" so as to
preserve this Newtonian concept.  (Note that the "m" in Eq. (1) is
numerically equal to the "rest mass" and to the "relativistic mass";
for a nonrelativistic system, the two are equal.)

As I said earlier, this fact was known even before Einstein; folks
used to talk about two different "inertial masses," one for forces
parallel to an object's velocity, and one for forces perpendicular to
it.  They gave up this particular silliness rather quickly, though,
and just decided that Eq. (1) did not apply to relativistic systems.


--
Matthew Austern              I dreamt I was being followed by a roving band of
(510) 644-2618               of young Republicans, all wearing the same suit,
matt@physics.berkeley.edu    taunting me and shouting, "Politically correct
austern@theorm.lbl.gov       multiculturist scum!"... They were going to make
austern@lbl.bitnet	     me kiss Jesse Helms's picture when I woke up.
From: matt@physics2.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: mass of quarks?
Date: 29 Jul 92 15:55:06
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
Distribution: usa
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics2.berkeley.edu
In-reply-to: sichase@csa2.lbl.gov's message of 29 Jul 92 18:48:09 GMT

In article <25025@dog.ee.lbl.gov> sichase@csa2.lbl.gov (SCOTT I CHASE) writes:

> Sure.  But it is much more complicated than you would think to assign an
> unambiguous number to that mass.

Indeed.  In the case of the heavy quarks (bottom, charm, and, when we
finally see it, top), the ambiguities are reasonably small, but in the
case of the light quarks (up, down, and strange), you have to specify
very carefully exactly what you mean by the mass of a quark.  I think
it is best to think of the "mass of a quark," in those cases, to be a
derived, theoretical number, and not an observed quantity.  

> To make things worse, if you could trap a free quark, you might very
> well find that they are massless!  That's because of "chiral
> symmetry restoration," which may or may not occur near the quark
> deconfinement phase boundary of QCD.  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?

Well, not quite.  The idea of chiral symmetry is that there is a
certain symmetry which, *if* quarks were massless, would be exact.
(Technically, this symmetry is performing independend flavor SU(3)
rotations on the left-handed and right-handed components of the
three light quarks.)  It is currently believed that these light quarks
are, in a certain sense, almost massless, so this symmetry is a good
approximation.

However, this symmetry is spontaneously broken.  So, as Scott said,
there should be some temperature where (approximate) chiral symmetry
is restored, and the world will exhibit an explicit chiral symmetry.
Even so, though, the quarks will have mass: the quark mass is due to
the breaking of the electroweak symmetry, not to the spontaneous
breaking of the chiral symmetry.

There is a theoretical debate about whether one of the light quarks
(the up quark) might actually be massless; the matter is not settled,
but it appears that it probably does have some small mass.

The best introduction to this subject that I know, by the way, is
_Weak Interactions and Modern Particle Theory_, by Howard Georgi.
--
Matthew Austern              I dreamt I was being followed by a roving band of
(510) 644-2618               of young Republicans, all wearing the same suit,
matt@physics.berkeley.edu    taunting me and shouting, "Politically correct
austern@theorm.lbl.gov       multiculturist scum!"... They were going to make
austern@lbl.bitnet	     me kiss Jesse Helms's picture when I woke up.
Newsgroups: sci.physics
From: jbaez@nevanlinna.mit.edu (John C. Baez)
Subject: Re: Chaos
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Tue, 21 Jul 92 21:13:42 GMT

In article <1992Jul20.194122.4545@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:

>     Work on existence and uniqueness and 'attractors' in 2-D with
>     usually special forcings and/or boundary conditions is hardly
>     of earth-shattering import.  Much more interesting from Foias
>     is his work on the Hopf functional formulation of turbulence
>     This is, of course, unrelated to 'chaos'.  Most people do not know
>     that the Navier-Stokes equations have been 'solved' (formally
>     by functional methods J. Rat. Mech. Anal. 1:87 (1952) and all
>     that followed from that work).  This could be very interesting
>     if we were better at functional integration.  I suggest that work in 
>     this area (of course, there are people working in this area)
>     is probably more potentially earthshaking, and there are applications
>     in other research backwaters (e.g. QM).

Hmm... I suppose I should just read the reference, but I wonder in what
sense the Navier-Stokes equation can be said to be "solved".  There is
no good global existence theorem for solutions, for one thing.  It's
true that the Navier-Stokes equation, like most decent PDE's, can be
written as a ODE with values in an infinite-dimensional vector space

df/dt = G(f)

and then "solved" by an integral equation

f(t) = f(0) + int_0^t G(f(s)) ds .

While this technique is really useful for studying PDE it would be
misleading to say to ordinary folks that the Navier-Stokes equation had
been solved if this was all there was to it.  Of course, you say it was
"solved" with quotes.   If it's possible to clarify without too much
work that'd be nice.

By the way, it's very enjoyable to read you writing about this stuff - as
opposed to the SSC - I guess I like physics more than politics.
Organization: University of Illinois at Chicago
Date: Monday, 27 Jul 1992 15:45:55 CDT
From: <U53644@uicvm.uic.edu>
Newsgroups: sci.physics
Subject: Re: Lense-Thring EFFECT (was Re: Gravitational "Magne
 <phfrom.153@nyx.uni-konstanz.de> <l6438mINN4de@pollux.usc.edu>
 <1992Jul17.145707.164250@dstos3.dsto.gov.au>

A question for those familiar with the theory behind this effect (the
gravitational analog of magnetism). Apparently, fairly extreme combinations of
mass density and acceleration are needed for it to be observed. Would extreme
enough conditions be found in the accretion disk around a black hole, close to
the hole, in the case in which the hole has a massive star as its' companion
(and is drawing off gas from that companion) ? If the eddies in that disk are
analagous to current loops, would they produce a force perpendicular to the
plane along which the eddy is alligned, creating an observable jet of material
coming out of the accretion disk ?

                                                  Joseph B. Dunphy
From: johncobb@ut-emx.cc.utexas.edu (John W. Cobb)
Newsgroups: sci.physics
Subject: Re: Jacob's Ladders (was Re: What are those things called...)
Date: 27 Jul 1992 21:13:45 GMT
Reply-To: johncobb@ut-emx.cc.utexas.edu (John W. Cobb)
Organization: The University of Texas at Austin

In article <1992Jul24.201747.18420@scott.skidmore.edu>,
datkatz@scott.skidmore.edu (david atkatz) writes:
|>
|>	So far, in describing the operation of a Jacob's Ladder,
|>	two people have described the rising of the heated,
|>	ionized air as the mechanism for the heavenward rise
|>	of the spark. This is what I, too, have always believed.
|>	Recently, however, I was told that a Jacob's Ladder will
|>	work in the horizontal position as well, and thus this
|>	simple mechanism is not what causes the spark to move
|>	from narrow to wide gap.  I have never tried the experiment.

Well, my intuition as a plasma physicists would say that the motion
is propelled by a J cross B force. The Jacob's ladder is narrow at the
bottom and gets wider at the top. The legs are metallic and therefore
equipotential (at frequencies below RF). Thus breakdown occurs at the
narrow end because that is where the Electric field is strongest. Now
once breakdown has occurred, you have set up a circuit where one leg
of the loop is a plasma arc. This loop is carrying current. The current
produces a Magnetic Field (Ampere's Law). Look at a small length of the
circuit. This small current element will feel a Lorentz force due to the 
magnetic field of all of the other elements. Now mechanical forces hold the 
legs and the base of the ladder in place, but the arc is free to move, and so
it does. you can also analyze this in terms of the "rules of thumb" one
learns in sophmore physics about how parallel currents attract and 
anti-parallel currents repel.

|>	
|>	Would some Ladder-possesing soul care to try this and
|>	report back?

I'm reporting back, but I'm not a ladder possessing soul; just another
arrogant theorist claiming to explain phenomena that I am not witnessing.

john w. cobb
jwc@fusion.ph.utexas.edu