Event Date Details:
Refreshments served at 3:30pm.
- Broida 1640
- Physics Department Colloquium
Quantum electrodynamics (QED) is a well established physical theory and its predictions have been conﬁrmed experimentally in various regimes and with extremely high accuracy. However, there are still areas of QED that deserve theoretical and experimental investigation, especially when physical processes occur in the presence of intense background electromagnetic ﬁelds, i.e., of the order of the so-called “critical” ﬁeld of QED . In the presence of electromagnetic ﬁelds of such a high strength even the vacuum becomes unstable and electron-positron pair production spontaneously occurs.
After a broad introduction on strong-ﬁeld QED, I describe diﬀerent regimes of this theory and introduce present and upcoming experimental eﬀorts to test it under such extreme conditions. As a prominent theoretical example of open problems, I focus on the so-called “radiation reaction” problem , which recently has been also addressed experimentally [3, 4]. The problem of radiation reaction in QED is intimately related to the behavior of the theory at short distances, i.e., at high energies. According to the so-called Ritus-Narozhny (RN) conjecture, strong-ﬁeld QED in an intense plane wave, unlike QED in vacuum, should become a strongly coupled theory already at moderately high energies . After reviewing the RN conjecture, I show how this tension between strong-ﬁeld QED and QED in vacuum has been recently resolved .
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