With their new technique, the group was able for the first time to measure collective excitations of the low-energy bosonic particles, the paired electrons
and holes, regardless of their momentum.
The study is the first definitive evidence of coupled electrons in a solid material too warm for superconductivity, a state in which paired electrons move with no resistance.
The combination of paired electrons and synchronized movement ensures that electric current can flow resistance-free.
Atoms that are missing electrons combine with atoms that have an extra electron, creating a stable molecule with evenly paired electrons
and a neutral electric charge.
On the other hand, atoms and molecules with paired electrons
like the noble gases of Group 8 on the Periodic Table tend to be unreactive.
In the high-temperature superconductors, paired electrons
seem to repel each other.
Since carbon tends to form covalent bonds, which contain paired electrons
, it seems an unlikely candidate to be magnetized.
The results may also provide insight into superconductivity, a form of superfluidity in which paired electrons
flow without resistance.
Last year, Zhi-Xun Shen of Stanford University and his collaborators used this technique, known as photoemission spectroscopy, to determine the binding force between paired electrons
in six high-temperature superconductors, including yttrium barium copper oxide.
For the line to move, the kinks have to separate the paired electrons
in front of them.
An atom or molecule with paired electrons
has no net spin and exhibits only mild, subtle magnetic effects.
However, the paired electrons
in BCS theory are in a quantum state (L=0) that does not allow them the freedom for the suggested collective action.