快猫短视频

THE first solid evidence that particles other than quarks can have fractional
charge has been uncovered by scientists in Israel. They have discovered
鈥渋maginary鈥� particles that carry one-third of the charge on the electron.

When matter conducts electricity, electrons flow through the material. 鈥淚t鈥檚
like a field full of horses,鈥� says Chris Ford, a physicist at the University of
Cambridge. 鈥淥ne runs in and another runs out the other end.鈥� Though the horse
that leaves the field is not the same as the one that enters, it鈥檚 useful for
accounting purposes to say that a single 鈥渜uasihorse鈥� makes the whole trip
itself. In a similar way, physicists imagine that electric currents are made up
of quasiparticles.

In this week鈥檚 Nature (vol 389, p 162), a team of scientists from
the Weizmann Institute of Science in Rehovot, Israel, report that when they
placed a flat conductor in a strong magnetic field, the current-carrying
particles had only one-third of the charge of the electron. 鈥淣obody believes
that the electron splits into three particles,鈥� says team member Rafi
de-Picciotto. 鈥淏ut the system behaves as if these quasiparticles move around
颈苍诲别辫别苍诲别苍迟濒测.鈥�

Physicists have claimed to have seen fractional quasiparticles before. In the
past, however, the evidence was inconclusive. This time it is convincing, says
Ford. Another group, led by Christian Glattli of France鈥檚 National Centre for
Telecommunications Research near Paris, have found the same results.