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Focus: Landmarks—Superconductor Quantizes Magnetic Field

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  Focus: Landmarks—Superconductor Quantizes Magnetic Field Sam Wormley <swormley1@gmail.com> - 2015-10-23 16:13 -0500
    Re: Focus: Landmarks - Superconductor Quantizes Magnetic Field jimp@specsol.spam.sux.com - 2015-10-23 22:45 +0000

#527725 — Focus: Landmarks—Superconductor Quantizes Magnetic Field

Focus: Landmarks—Superconductor Quantizes Magnetic Field
> http://physics.aps.org/articles/v8/102


> Two experiments reported in 1961 showed that the magnetic field
> passing through a hollow superconducting cylinder is quantized,
> meaning that it can exist only in certain discrete amounts, multiples
> of a universal magnetic flux unit. The discovery confirmed a
> prediction made a decade earlier except that the flux unit was half
> what the earlier argument said it should be. That difference, further
> theoretical analysis showed, firmly established the idea that
> superconducting electrons work in pairs.
>
> In a book published in 1950, before any satisfactory theory of
> superconductivity existed, Fritz London of Duke University in North
> Carolina offered a simple argument for the quantization of magnetic
> flux passing through a superconducting loop. If current-carrying
> electrons in the superconductor were described by a quantum wave
> function that ran continuously around the loop, the wave function had
> to be periodic—each time around the loop it had to take on the same
> values. This restriction, London found, meant that the magnetic field
> induced by the superconducting current in the interior of the loop
> would be quantized. He predicted that the smallest possible magnetic
> flux—the universal unit—would be Planck’s constant times the speed of
> light, divided by the charge of the electron: hc∕e [1].
>
> In the late 1950s, graduate student Bascom Deaver worked with William
> Fairbank at Stanford University in California to test this
> prediction. To make a superconducting ring, Deaver electroplated a
> thin layer of tin onto a copper wire. Deaver and Fairbank tested two
> different tin cylinders, each about one centimeter long, with an
> internal diameter of just over 10 micrometers.
>
> Placed in a magnetic field and cooled in liquid helium to less than
> 3.7 degrees Kelvin, the tin became superconducting. The researchers
> then turned off the magnetic field. To measure any magnetic flux that
> remained trapped within the cylinder, they vibrated it back and forth
> at 100 hertz and measured the electrical signal generated in nearby
> coils of wire. They found that the flux through the cylinder
> increased in a stepwise fashion with increasing strength of the
> original applied field. The height of each step, however, was half
> the flux unit that London had predicted.



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#527742 — Re: Focus: Landmarks - Superconductor Quantizes Magnetic Field

Sam Wormley <swormley1@gmail.com> wrote:
> Focus: Landmarks - Superconductor Quantizes Magnetic Field

Now if it were about nano quantum fields the shit head would be in
a frenzy.

Have you ever wondered what your life might have been like if you had
the competence to do more than just copy the words of others, spamming
piece of shit?


-- 
Jim Pennino

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