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New particle explains odd behavior in cuprate superconductors
Posted on Tuesday, July 17, 2007 @ 21:51:28 UTC by vlad
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New fundamental particles aren’t found only at Fermilab and at other
particle accelerators. They also can be found hiding in plain pieces of
ceramic, scientists at the University of Illinois report.
The newly formulated particle is a boson and has
a charge of 2e, but does not consist of two electrons, the scientists
say. The particle arises from the strong, repulsive interactions
between electrons, and provides another piece of the high-temperature
superconductivity puzzle.
Twenty-one years ago, superconductivity at high
temperatures was discovered in copper-oxide ceramics (cuprates).
Existing explanations of superconductivity proved inadequate because,
unlike low-temperature superconductors, which are metals, the parent
materials from which all high-temperature superconductors arise are
insulators.
Now, a new theory suggests something has been overlooked. “Hidden
in the copper-oxide materials is a new particle, a boson with a charge
of 2e,” said Philip Phillips, a professor of physics at Illinois.
Surprisingly, this boson is not formed from the elementary
excitations – that is, electrons and ions. Instead, the particle
emerges as a remnant of the strong interactions between electrons in
the normal state.
“High- and low-energy scales are inextricably coupled in the
cuprates,” Phillips said. “Normally, when you remove a single electron
from most systems, one empty state is created. In the cuprates,
however, when you remove an electron, you create two empty states –
both of which occur at low energy, but paradoxically, one of the states
comes from the high-energy scale.”
Experimental evidence of this “one to two”
phenomenon was first reported in 1990 and explained phenomenologically
by University of Groningen physicist George A. Sawatzky (now at the
University of British Columbia) and colleagues. What was missing was a
low-energy theory that explained how a high-energy state could live at
low energy.
Phillips, with physics professor Robert G. Leigh and graduate
student Ting-Pong Choy, have constructed such a theory, and have shown
that a charged 2e boson makes this all possible.
“When this 2e boson binds with a hole, the result is a new
electronic state that has a charge of e,” Phillips said. “In this case,
the electron is a combination of this new state and the standard,
low-energy state. Electrons are not as simple as we thought.”
The new boson is an example of an emergent phenomenon – something
that can’t be seen in any of the constituents, but is present as the
constituents interact with one another.
By constructing a low-energy theory of the cuprates, the
researchers have moved a step closer to unraveling the mystery of
high-temperature superconductivity.
“Until we understand how these materials behave in their normal
state, we cannot understand the mechanism behind their high-temperature
superconductivity,” Phillips said.
Source: University of Illinois at Urbana-Champaign
Via: http://www.physorg.com/news103887917.html
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Re: New particle explains odd behavior in cuprate superconductors (Score: 1)
by Koen on Thursday, July 19, 2007 @ 13:44:43 UTC
(User Info | Send a Message) http://no.nl/tesla | A 2e boson? An electron, one of the members of the fermion family, obviously can bind to another electron, forming a 2e boson. This must be the case, since recombination with a "hole" yields one single electron. There is no other way to understand this 2e boson as made up of two electrons.
If a lot of these 2e bosons can be created, these particles don't obey the usual fermion statistics, and therefore can form large "electron" clusters, already observed by Ken Shoulders (known as charge-clusters). These charge clusters have a strong negative charge.
Ken Shoulders also showed that such clusters can exist outside a superconducting material.
Prof. R.M. Santilli showed that two electrons that usually form the covalent bond between two atoms, can also form a 'bond' (form a cooper pair) such that this 2e boson causes a strong magnetic polarization of the atom which explains Santilli's magnecules and magnegas.
The 2e boson theory is interesting, because the older theory of 'the Cooper pair' of electrons says that such pairs can only exist in a superconducting solid. In theory, a 2e boson is an entity of its own with an intrinsic stability, and should also be stable OUTSIDE a superconducting material, as already shown by Ken Shoulders. This idea certainly contributes to Santilli's covalent-bond electrons, that also form a 2e boson, for instance in a CO (carbon-monoxide) molecule.
Big question is: how can two electrons form a 2e boson? One theory is (by a colleque of Santilli) that these two electrons continuously tunnel through the potential barrier that is in between them. So the two-electron-bond is a tunneling effect.
Quote: "Instead, the particle
emerges as a remnant of the strong interactions between electrons in
the normal state."
I was able to show that 'discontinous classical currents' that consist of many tunneling electrons cause unusual classical electric effects, such a longitudinal Ampere forces, and longitudinal electro-scalar waves.
And then we are back to Nikola Tesla.
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