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Meissner Effect preclude a "self-created current" ??

Meissner Effect preclude a "self-created current" ?? - Chemistry Forum

Meissner Effect preclude a "self-created current" ?? - Chemistry Forum. Discuss chemical reactions, chemistry.


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  #1  
Old 10-09-2003, 04:57 PM
Archimedes Plutonium
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Default Meissner Effect preclude a "self-created current" ??



The Meissner effect with the exclusion of a magnetic field brings to
question as to whether or not a self created current can arise. The
Hypothesis that superconductivity is maximal electronegativity
exchange with electropositivity creating a current brings into
question as to how this would conform to the Meissner effect. Because,
we know from Maxwell theory that current creates magnetism and vice
versa.

Perhaps the Meissner effect is the self-created-current when lowering
temperature. So that when lead is lowered to 1.8 K it is
superconductive and the measurement of the Meissner effect of lead at
1.8 K is tantamount to the measurement of a self created current.

And that the Conduction Band theory of solo atoms becomes
electronegativity exchange with electropositivity. Conduction Band
theory is merely an extreme form of electronegativity exchange with
electropositivity. Experimental test: the most conduction band
elements are silver and gold and copper. We should be able to
configure a Na to Cl arrangement which is Electronegativity to
Electropositivity that matches equally a gold Conduction Band. Where
in the end analysis we have equality of conduction.

Such that superconductivity of solo atoms is because Conduction Band
is electronegativity exchange electropositivity and these constitute a
class of superconductors and then there are the compound-elements that
are superconductive because they are less of the Conduction Band and
more of the electronegativity exchange electropositivity.

I do not think anyone has taken the high temperature cuprates and
looked for a self created current, nor for mercury or lead in the 4 to
1 degree Kelvin. Nor have they cooled mercury down to 1 degree Kelvin
and then looked for a spontaneous Meissner Effect. That is a Meissner
Effect of adding a magnet to the experiment but never adding any
outside electric current.

So the question comes down to whether a Self Current is created due
merely to the lowering to very cold temperatures and if created
whether this self current is equal to the Meissner Effect. And if so,
then is the Meissner Effect tantamount to a self created current. The
other possibility is that there is no self created current and that
the Meissner Effect is proof that such a current cannot exist because
of Maxwell theory that wherever there is "no" magnetism there is no
current.

Nothing in the literature suggests anyone has spotted a tiny self
creating current dependent only the lowering of temperature. And I
guess no-one really has taken a scientific look for such.

Archimedes Plutonium
whole entire Universe is just one big atom where dots
of the electron-dot-cloud are galaxies
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  #2  
Old 10-09-2003, 06:04 PM
Graham Lee
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Default Meissner Effect preclude a "self-created current" ??

Archimedes Plutonium wrote:

No it doesn't; the supercurrent only exists in the presence of an
external field driving it. Reduce a superconductor to below T_c with no
external field, and bingo you get no current.
--
Graham.

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  #3  
Old 10-10-2003, 02:13 AM
Archimedes Plutonium
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Default Meissner Effect preclude a "self-created current" ??

Graham Lee <[Only registered users see links. ].ac.invalid.uk> wrote in message news:<bm47un$b69$[Only registered users see links. ].ac.uk>...

Graham, does the Meissner effect exist or occurr only in the prescence
of a external field driving it? If so, what is the math relationship
for the amount of external field and the amount of Meissner effect
that can occurr.

Some of these questions sound so simplistic, but these questions would
be familar to those who actually have direct experience with
superconductivity.

So if we take YBa2Cu3Ox and lower it to 95K and apply no external
field, then Graham, is there no Meissner effect until a current is
applied? That is what you are saying, Graham, that no Meissner effect
exists until a external electric field is applied. And you maybe
correct.

But what I am suspicious of is the idea that when 95K is reached, that
the yttrium-barium-copper-oxide has reached a point where the
electronegative pull of electrons and electropositive push of
electrons is so enormous that a self-current is created and that is
the "no resistance".

So, when 95K is reached is there a Meissner Effect without any
external electric field?? Perhaps you, Graham works in such labs and
can tell us immediately.

And if Graham is 100% correct and I am 100% wrong, then by logic, can
we state that the Meissner effect is a proof that no self current
arises as the temperature is cooled to 95K. For the exclusion of a
magnetic field by superconductors may provide the proof that no
self-current arises.

I am not talking about a heavy or big magnet but a very very tiny
magnet for a milliampere current of self-current. Graham, do you have
a magnet of the parameter of milliampere equivalency??

I do not have enough data and information of superconductivity and
thus have to ask simplistic questions.

Archimedes Plutonium
whole entire Universe is just one big atom where dots
of the electron-dot-cloud are galaxies
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  #4  
Old 10-10-2003, 11:45 AM
Graham Lee
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Default Meissner Effect preclude a "self-created current" ??

Archimedes Plutonium wrote:

The Meissner-Ochsenfeld effect is the phenomenon of currents arising in
a superconductor *to oppose an external magnetic field*, so that the
magnetic flux is excluded from the bulk of the superconductor.
Therefore, no external magnetic field=>no Meissner-Ochsenfeld effect.


M=-H_{applied}. The magnetisation of a superconductor is equal to, but
in the opposite direction to, the applied magnetic field. Therefore if
H_{applied} is 0, the magnetisation is 0. No effect.


I said "no external field"; as you were discussing the Meissner effect I
guessed that it was good to assume that we were discussing magnetic
fields. But you mention electric fields, so let's look at that.
If a superconductor is placed in an electric field, then the Cooper
pairs (bound states of two electrons) will accelerate in the opposite
direction to the field gradient. There is no Meissner effect here to
first order, as there is no magnetic field. However the motion of the
charge carriers will induce a magnetic field, so *in an applied electric
field* a magnetic field will also exist, but as before the
superconductor will confine the field to its surface.
Without an electric field, nothing will cause the Cooper pairs to
accelerate, therefore they will remain in a single inertial frame. No
motion==no magnetic field==no Meissner.


Nope. There is no electropositive effect on the electrons; the
attractive potential is actually mediated by phonon interactions (see,
for instance, Cooper, Phys Rev *104*(1956) 1189-1190). Most of the
electrons are sitting in a degenerate Fermi gas as is the case in a
normal metal; the rest are in these bound pairs which are constrained to
have zero momentum (and in most cases zero spin), in the absence of any
applied 'push'. There is no current.


No field spontaneously appears without an applied cause (example: Doll
and Naebauer, Phys Rev Lett *7*(1961) 51-52; this is also regularly
explored in undergraduate practical labs). Without any field, no
current exists to counteract the field. No current==no magnetisation
field==no Meissner.


No self-current *spontaneously* arises, no. You need an external field
to generate one.


Just use a variable electromagnet.


No problem, see if you can get a hold of the references given above. I
think the APS have archived all the Physical Review back-issues on their
web site.

--
Graham.

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  #5  
Old 10-10-2003, 05:44 PM
Archimedes Plutonium
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Default accomodate Maxwell Eq to house Meissner Effect Re: Meissner Effectpreclude

Fri, 10 Oct 2003 12:45:35 +0100 Graham Lee wrote:

Hope this post gets through as my local ISP has been acting sporadically as lately and if it does not get
through will have to repeat this post via Google.


Graham, I am guessing that the Maxwell Equations have nothing to suggest a Meissner Effect and that try as
one may, they cannot get a Meissner Effect from the 4 Maxwell Equations. I am guessing that the Meissner
Effect is implying or suggestive of a "monopole structure", and that if we were to tinker around to modify
the Maxwell Equation that specifically talks of "no magnetic monopole" that it is within this no magnetic
monopole law that we can find room to build a equation to accomodate a Meissner Effect.

Perhaps superconductivity is a Quantum Physics and not a Classical Physics.

And to really understand superconductivity, it is imperative that we figure out if it is 100% Classical
Physics. Of course, Cooper pairing is 100% Quantum with 0% Classical.

Graham, it seems to me, at this juncture, that the best logical road to take is to take the 4 laws of
Maxwell theory and given those 4 laws, try to modify those 4 laws such that Meissner Effect is included.
Graham, question: what is the most simple way of altering the Maxwell Equations such that Meissner Effect
exists incorporated into the Maxwell Equations? Do we have to throw out the monopole law of Maxwell
theory?? Or do we have to modify the monopole law? Or perhaps we have to tinker with Faraday's law of
magnetic induction. Whatever, how do we change the Maxwell laws such that Meissner Effect is represented
in the Maxwell theory. I believe once we have answered that Logical Road, then we can better stand back
and say with some confidence that Superconductivity is 100% Classical Physics with no new strangeness of
Quantum Physics. Or, whether we indeed have to say that Superconductivity is a whole new ball-of-wax
quantum strangeness and that Cooper pairing maybe not all bad.


Odd that my mind was thinking that those heavy Japanese superconducting trains had to have some "applied"
energy in the form of current flow in the train track in order for the train to be held up but instead the
"lowering of temperature"
to Tc is what holds the train up. Thus there is a direct relationship between the energy of lowering the
temperature to Tc and the force which holds up a train.

We have Conservation of Energy, so can someone tell me how much energy is spent in lowering the
temperature to Tc and keeping it at Tc versus the energy cost in gravity of holding up a train?


Graham, I was never able to see how a mechanism of Cooper pairing, or as you call it a electron-bound
state can give rise to zero resistance. I realize that pairing is a sort of analogy, just as dancing
couples paired in a room would be easier to exit flow in case of a fire rather than willy-nilly exit flow.
So the question remains has how does a Pairing or bound state of electrons eliminate resistance. My past
theory that superconductivity is the replacement of photon messengers by neutrino messengers since
neutrinos pass through matter with no resistance is a theory that immediately offers logical commonsense
as to the elimination of resistance. But the Cooper pairing theory seems to never adequately address the
question as to how resistance is eliminated. The flow of electrons can be more orderly if the electrons
are paired but it still does not eliminate resistance. Because like the dancing pairs, they still bump
into one another.


I never liked phonons either for that is an example, an extreme example of where physics runs into
problems and then throws in ad-hoc solutions, whereas the real problem is the initial theory of BCS
itself. Ad-hoc-ery is tantamount to epicyclery, in my estimation and all pointing back to a theory that is
incompetent.

Instead of Cooper pairs and phonons and Fermi gas, here is a better and more simple view of
Superconductivity. You approach 95K in the above Yttrium superconductor. As you near 95K you cause the
electronegative atoms to arrange themselves with the electropositive atoms into a geometrical
configuration to where the pull of the electronegative and the push of the electropositive is so "orderly"
that as you apply a external current of electrons they are wisked along by those "pushes and pulls".

Analogy: England roads and the cars and lorries on the roads as normal conduction with its resistance
along the way. But now you make the England roads superconduct instead of normal-conduct. And what you do
is make all roads straight and you refit all cars and lorries such that as they travel down any road they
are pushed and pulled along by "boom arms" alongside the roads. So that as every car travelling down a
road moves from one boom arm to another they are given a accelerating boost. The boom arms are the
Electronegative atoms pulling and the Electropositive atoms pushing. So that the energy in keeping
superconductors at Tc is transformed into electronegative pulls and electropositive pushes of electrons
applied.


Okay, will have to look up those references.

But more important, I have to somehow try to make the Maxwell Equations modified enough so that they
incorporate a Meissner Effect. And after I do that I can best stand back and look at this entire issue of
Superconductivity and judge better as to whether I am dealing with a Quantum strangeness phenomenon, or
whether Superconductivity is totally explainable as a Classical Physics phenomenon. I am not a betting
man, but if force to bet I would say superconductivity is 100% Classical physics and that the Meissner
Effect is easily appended into the Maxwell Equations. And that Cooper pairing is illogical in eliminating
resistance whereas Electronegativity theory can easily eliminate resistance.

Archimedes Plutonium, [Only registered users see links. ]
whole entire Universe is just one big atom where dots
of the electron-dot-cloud are galaxies

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  #6  
Old 10-10-2003, 08:04 PM
Starblade Darksquall
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Default Meissner Effect preclude a "self-created current" ??

Graham Lee <[Only registered users see links. ].ac.invalid.uk> wrote in message news:<bm47un$b69$[Only registered users see links. ].ac.uk>...

Isn't the Meissner efffect caused by monopoles?

(...Starblade Riven Darksquall...)
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  #7  
Old 10-11-2003, 12:14 PM
Graham Lee
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Default accomodate Maxwell Eq to house Meissner Effect Re: Meissner Effectpreclude

Archimedes Plutonium wrote:

Not true; the London equations describing superconductivity show that
the phenomenology of superconductivity - including the Meissner effect -
can be described within the framework of the Maxwell Equations.


Well, as the Maxwell Eqns can already accomodate the Meissner effect,
this is superfluous. The current 'BCS Theory' of superconductivity
(Bardeen, Cooper and Schrieffer, Phys Rev *108*(1957) 1175-) - which is
in excellent agreement with experiment - does not require magnetic
monopoles and yet explains many of the observations regarding
superconductors. Let me stress this point: there is as yet *no
evidence* for magnetic monopoles.


Superconductivity is only understood within the realms of quantum
physics. However, by the time you start to consider macroscopic
samples, you need some macroscopic approximations to the quantum theory.
For discussing electromagnetism, this means the Maxwell Equations.
For superconductors, either the London theory or Ginzburg-Landau theory
are often employed.


We don't need to understand whether or not it is classical or quantum
physics. Superconductors are made of protons, neutrons and electrons,
and so quantum physics will be necessary to describe superconductivity.
Classical physics is a good, simple approximation to quantum physics
that can be used within certain realms.


Unnecessary; the Meissner effect can already be incoroporated into the
Maxwell Equations through a simple substitution: B=0.


Unnecessary; see above.


There is *no evidence* of the existence of magnetic monopoles.
Superconductors can be understood *without* magnetic monopoles. The
Meissner effect *is not evidence* of magnetic monopoles.


It already works; no tinkering involved.


You'd be hard pushed to do that; quantum effects can be directly
observed in experiments involving superconductivity.


Cooper pairing is neither bad nor good; it is the mechanism that is
understood to lead to superconductivity in certain substances.


You're neglecting the external magnetic field that is applied by the
magnets in the situation. This is why such technology is called MagLev:
Magnetic Levitation.


I'm not an engineer on the MagLev project, so can't dig out a set of
numbers. However, energy is supplied by the external magnetic field to
counteract the gravitational potential. This is the physical explanation.


Read the reference given in my last post to Cooper, and the BCS
reference above. These explain how it works.


No it's not an analogy at all. The pairing has been experimentally
verified; look up Flux Quantisation.


There are no neutrinos in superconductivity. It is an electromagnetic
effect; neutrinos cannot interact electromagnetically.


When the Cooper pairs are formed they condense into the same energy
state. The electrons' wavefunctions are constrained in such a way that
collisions become impossible. This is explained in the BCS reference above.


Excuse me? Phonons aren't an 'ad hoc' solution; the effects of phonons
can be directly observed in (for instance) neutron scattering. Theories
involving phonons successfully explain many phenomena, such as Debye's
theory of heat capacity in solids, or the ability of the BCS theory to
explain the isotope effect in superconductors. Phonons are the result
of quantisation of lattice vibrations; they are merely another way of
describing the normal modes of a crystal structure.


It's a good job that this BCS theory isn't ad hoc then, isn't it?
Unlike the magnetic monopole theory. Remember the complete lack of
evidence for magnetic monopoles.


Try this; not all solids are ionic.


Unnecessary; see the London equations.


Why should you want to remove the quantum physics? Not only is it
incredibly successful, but there is *evidence* of quantisation in
superconductivity. Evidence such as the flux quantisation.


It cannot be a non-quantum phenomenon as there is evidence against it
being so. Remember; 'Classical' physics is merely an approximation to
quantum physics for large numbers of quanta at large energies; just as
Galilean relativity is a low-velocity approximation to Einstein's
special relativity.


Graham.

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