Are there any primary experiments used to try to prove the Quantum Electrodynamics theory? Were they all successful, and how were they performed? Also, I was wondering where Feynman's equations are used primarily now, everyday.


closed as too broad by Emilio Pisanty, Qmechanic Jul 15 '18 at 13:10

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  • $\begingroup$ You can test QED using high power lasers. ELI-NP will have an experimental program dedicated to test QED features. $\endgroup$ – Andrei Geanta Jul 15 '18 at 10:16
  • $\begingroup$ You may want to split this into 2 questions. Additionally, a question like "Where are Feynman's equations used now?" is way too broad for physics SE. $\endgroup$ – user191954 Jul 15 '18 at 10:20
  • $\begingroup$ The equations behind Feynman diagrams are mostly used in Particle Physics. They are experimentally tested in particle accelerators (like LHC). $\endgroup$ – Andrei Geanta Jul 15 '18 at 10:30
  • $\begingroup$ As far as I know, ESR (Electron Spin Resonance) gives the best comparison of the theory with experiment. $\endgroup$ – Pieter Jul 15 '18 at 12:02
  • $\begingroup$ Experiments with multiple generations of accelerators have all proven QED. The deviation of the electron and muon g-factor from its Dirac value of 2 is perhaps the most accurate confirmations. Also check out the Lamb shift. $\endgroup$ – my2cts Jul 15 '18 at 13:54

Measuring the fine structure constant was a great validation of quantum electrodynamics.

The experiment is still being refined"

Refining the fine-structure constant

The fine-structure constant, α, is a dimensionless constant that characterizes the strength of the electromagnetic interaction between charged elementary particles. Related by four fundamental constants, a precise determination of α allows for a test of the Standard Model of particle physics. Parker et al. used matter-wave interferometry with a cloud of cesium atoms to make the most accurate measurement of α to date. Determining the value of α to an accuracy of better than 1 part per billion provides an independent method for testing the accuracy of quantum electrodynamics and the Standard Model. It may also enable searches of the so-called “dark sector” for explanations of dark matter.

  • $\begingroup$ But QED does not predict a number for alpha. I would rather say that the anomalous g-factor of the electron and the muon are very sensitive tests. $\endgroup$ – Pieter Jul 15 '18 at 11:59
  • 1
    $\begingroup$ @Pieter The point is that if you measure $\alpha$ in different ways, QED predicts you'll get the same result. (This is just like how Newtonian mechanics predicts that measuring $F/a$ and $F_g / (GM/r^2)$ will give the same result.) $\endgroup$ – knzhou Jul 15 '18 at 12:52

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