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Résumé |
Vacuum breakdown by particle-antiparticle pair creation under intense electric field, introduced by Sauter
and Schwinger, is a basic non-perturbative prediction of quantum electrodynamics. Its high-energy
physics experimental demonstration remains elusive as the threshold electric fields are extremely strong
and beyond current reach, even for the light electron-positron pairs.
Here we put forward a mesoscopic variant of the Schwinger effect in graphene, which hosts Dirac
fermions with an approximate electron-hole symmetry. Using DC transport and radiofrequency noise
measurements, we report on universal one-dimensional Schwinger conductance at the pinchoff of ballistic
graphene transistors. Strong pinchoff electric fields are concentrated within approximately 1µm of the
transistor’s drain; they generate a giant Klein collimation that acts as a seed for 1D Schwinger electron-
hole pair creation at saturation. The theoretical prediction for 1D Schwinger effect is quantitatively verified
in its full non-perturbative development. These observations give clues to current saturation limits in
ballistic graphene, and pave the way for further quantum electrodynamics experiments in the laboratory. |
