Two labs independently measure e/4 charge in the ν = 1/2 quantum Hall state

EPFL and the Weizmann Institute independently measured the fractional quasiparticle charge in the ν = 1/2 fractional quantum Hall state, obtaining 0.250 ± 0.013 e and 0.249 ± 0.018 e — consistent with e/4. The result does not prove non-Abelian order but sets a benchmark for future tests of topological order.

• Quasiparticle charge measured at 0.250 ± 0.013 e and 0.249 ± 0.018 e, matching e/4
• Electrons were confined to a 70-nanometer gallium arsenide layer under a strong magnetic field
• The ν = 1/2 energy gap is about 10 times larger than that of the ν = 5/2 state
• The e/4 measurement cannot distinguish Abelian from non-Abelian states; braiding tests are needed