Re: Can electron really absorb acoustic wave?? how?



John Sefton wrote:



EMy wrote:

This is exactly what is claimed in the explanations of the
formation of cooper pairs in superconductor. Doesn't anyone have
problem with that concept? What if cooper pairs are created by
other mechanisms and not what Leon Cooper claimed.

http://www.ornl.gov/info/reports/m/ornlm3063r1/pt3.html

quoted in part

"The understanding of superconductivity was advanced in 1957 by
three American physicists-John Bardeen, Leon Cooper, and John
Schrieffer, through their Theories of Superconductivity, know as
the BCS Theory. The BCS theory explains superconductivity at
temperatures close to absolute zero. Cooper realized that atomic
lattice vibrations were directly responsible for unifying the
entire current. They forced the electrons to pair up into teams
that could pass all of the obstacles which caused resis tance in
the co nductor. These teams of electrons are known as Cooper
pairs.Cooper and his colleagues knew that electrons which
normally repel one another must feel an overwhelming attraction
in superconductors. The answer to this problem was found to be in
phonons, packets of sound waves present in the lattice as it
vibrates. Although this lattice vibration cannot be heard, its
role as a moderator is indispensable.

"According to the theory, as one negatively charged electron
passes by positively charged ions in the lattice of the
superconductor, the lattice distorts. This in turn causes phonons
to be emitted which forms a trough of positive charges around the
electron. Figure (4) illustrates a wave of lattice distortion due
to attraction to a moving electron. Before the electron passes by
and before the lattice springs back to its normal position, a
second electron is drawn into the trough. It is through this
process that two electrons, which should repel one another, link
up. The forces exerted by the phonons overcome the electrons'
natural repulsion. The electron pairs are coherent with one
another as they pass through the conductor in unison. The
electrons are screened by the phonons and are separated by some
distance. When one of the electrons that make up a Cooper pair
and passes close to an ion in the crystal lattice, the attraction
between the negative electron and the positive ion cause a
vibration to pass from ion to ion until the other electron of the
pair absorbs the vibration. The net effect is that the electron
has emitted a phonon and the other electron has absorbed the
phonon. It is this exchange that keeps the Cooper pairs together.
It is important to understand, however, that the pairs are
constantly breaking and reforming. Because electrons are
indistinguishable particles, it is easier to think of them as
permanently paired. Figure (5) illustrates how two electrons,
called Cooper pairs, become locked together

There are two kinds of electrons.
This is because when you spin a
pair of charges clockwise wrt the observer
they can separate two ways; with the negative
on top or negative on the bottom.


Imagine a drill with a bit that extends
out both sides. You stand on the drill and
look one way, it is turning clockwise. You stand
looking the other way, and the bit is turning
counterclockwise.
Now put your proton on close to the drill
and your electron at the end. They both
turn the same way, say clockwise, and are
repelling each other magnetically while still
attracting electrically. Diagram it like this:
e S>N.....N<S p<drill>

Now put a proton-electron pair on the other
side of your drill. From the drill's
point of view they are turning *counter*clockwise.
But they still repel each other magnetically
while attracting electrically, however their
magnetic fields are opposite:
                <drill> p N<S.....S>N e
Now put the two together while
throwing a couple of neutrons in to help
which I won't get into:

   e S>N.....N<S p <drill> p N<S.....S>N e

Notice: the two protons are attracting each other
magnetically. Take out everything except the
electrons:

                e S>N..........S>N e

Notice: the two electrons attract each other magnetically.
This allows them to share their three-dimensional repeating orbit.

In a Cooper pair.

John


.

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