Capturing a Single Positron Makes History in Physics

On October 22, 2026, the journal Physical Review Letters reported a major physics breakthrough achieved by the subatomic particle research group at Northwestern University. Scientists successfully isolated and trapped a single positron—the positively charged antimatter counterpart of the electron—inside an electromagnetic trap for over 3 months without it annihilating with any surrounding matter.

This achievement represents the first quantum cyclotron for a single positron operating in its completely stable ground state. This progress was made possible by building an advanced Penning trap featuring a highly uniform magnetic field of 5.8 Tesla, coupled with an advanced vacuum system producing a pressure of less than 10 to the minus 17 Torr inside an insulated chamber cooled with liquid helium to 300 millikelvin above absolute zero.

These exceptional conditions froze the positron's motion and eliminated any thermal disturbances, allowing researchers to monitor the cyclotron frequency and single-particle spin flips using non-destructive quantum electronic probes that neither touch the particle nor force it out of its lowest quantum state. This experimental success paves the way for the most precise test in the history of the physical symmetry theory known as CPT symmetry, through the direct comparison of magnetic properties between the positron and the electron with an accuracy reaching one part in 10 to the 13, aiming to unravel the mystery of the matter-antimatter asymmetry and why visible matter dominates the universe's galaxies following the Big Bang.