Department of Physics Colloquium

Guest speaker: François Fillion-Gourdeau INRS-EMT
Thursday, 16 November 2017 - 3:00 pm to 4:00 pm
Off-campus address: 
25 Templeton St, room 233
Registration required: 
Cost to attend: 
Free of charge
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Title: The Schwinger effect in QED and condensed matter systems

Abstract:  The Schwinger effect consists in the spontaneous creation of electron-positron pairs from a strong homogeneous electric fields. This is a long lasting prediction of quantum electrodynamics (QED) that was first studied by Sauter, Heisenberg and Euler in the 30's, but for which a more rigorous QED treatment was given by Schwinger in the 50's. Many theoretical and experimental proposals using different field configurations have been put forward to verify this hypothesis, but so far, it has eluded all experimental investigations, mostly because the particle production rate is insignificant with actual electric fields generated in laboratories. Even in high intensity lasers, the typical field strength is many orders of magnitude below the Schwinger field (1.3e18 V/m) at which electron-positron pair production becomes important. Nevertheless, major improvements in laser technologies in the last few decades have stimulated a lot of efforts on the theoretical side and given some hope that the Schwinger effect could be detected in the near future.

In this talk, I will present three theoretical proposals where the Schwinger effect is enhanced, resulting in more pairs produced for a given field strength. The first one is based on the dynamically assisted Schwinger effect, combined with pulse-shape optimization. The second one, named the resonantly enhanced pair production mechanism, utilizes resonance effects in highly charged ions to increase the pair yield. Finally, the last proposal is a different approach whereby the Schwinger effect is simulated by relativistic-like charge carriers in Dirac materials, such as graphene. Advantages and limitations of every approach will be discussed.

Refreshments will be served at 2:30 p.m. (BEFORE the seminar) in room ARC 233