University of Connecticut

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Particle, Astrophysics, And Nuclear Physics Seminar

Monday, April 26, 2021
2:00pm – 3:00pm

Storrs Campus

Zach Harris, Department of Physics, University of Connecticut

Resurgence and the Euler-Heisenberg Effective Action

Perturbation theory is one of the most accessible tools we have for studying quantum systems and quantum field theories. For most interesting problems, these expansions in the relevant small parameter are formally divergent. However, resummation techniques have been developed to make sense of such expansions, and provide access to a rich substructure relating perturbative physics to non-perturbative physics which was obscured by the divergence. This unification of perturbative and non-perturbative physics is a manifestation of resurgence — a mathematical phenomenon which we use to study perturbative expansions in QED. We present a modified Padé-Borel analysis of the one-loop and two-loop Euler-Heisenberg QED effective action, and demonstrate with remarkable precision our ability to re-sum weak magnetic field expansions to learn about the strong magnetic field and electric field regimes. At two-loop order, we successfully decode novel, non-perturbative structure in the Schwinger pair-production rate — the rate at which a constant electric field will polarize the vacuum.


Prof. G. Dunne

Physics Department (primary), College of Liberal Arts and Sciences, UConn Master Calendar

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