Do Photons Cast Shadows?

Thanks to CuriosityStream for their support. Go to http://www.curiositystream.com/minutephysics to watch Particle Fever and get Nebula!

Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics
Link to Patreon Supporters: http://www.minutephysics.com/supporters/

This video is about two-photon (gamma-gamma) physics, and how photons can interact with each other - either mediated by a passing lepton, or gravitationally via lensing, or via vacuum fluctuation pair production of vertical particles (electron-positron pair, for example). This is the so-called "box diagram" feynman diagram.

REFERENCES

Water waves interact with each other (weakly nonlinear shallow water waves)
https://en.wikipedia.org/wiki/Korteweg%E2%80%93deVriesequation
http://mathworld.wolfram.com/Korteweg-deVriesEquation.html

Paper: Absorption of Very High Energy Gamma Rays in the Milky Way
https://arxiv.org/pdf/1608.01587.pdf

Paper: Observing light-by-light scattering at the Large Hadron Collider (LHC)
https://arxiv.org/pdf/1305.7142.pdf

Mass-Energy Scale
http://labs.minutelabs.io/Mass-Energy-Scale/

Optical Depth
https://en.wikipedia.org/wiki/Opticaldepth

The electromagnetic spectrum and photon energies
http://labman.phys.utk.edu/phys222core/modules/m6/The%20EM%20spectrum.html

Gravitational Lensing
http://andybohn.com/research/lensing.html

Ask an Astrophysicist on gamma ray scattering and energies in cosmology
http://teacherlink.ed.usu.edu/tlnasa/reference/imaginedvd/files/imagine/docs/askastro/answers/970412e.html

Measuring Vacuum Polarisation with High Power Lasers
https://arxiv.org/pdf/1510.08456.pdf

Detecting vacuum birefringence with X-ray free electron lasers and high-power optical lasers
https://indico.desy.de/indico/event/12654/session/2/contribution/8/material/slides/0.pdf

Vacuum birefringence in the head-on collision of XFEL and optical high-intensity laser pulses
https://arxiv.org/pdf/1807.03302.pdf

ATLAS makes first direct detection of Light-by-light scattering at the LHC
https://atlas.cern/updates/press-statement/atlas-sees-first-direct-evidence-light-light-scattering-high-energy

Two Photon Physics
http://www.hep.ucl.ac.uk/opal/gammagamma/gg-tutorial.html
https://en.wikipedia.org/wiki/Two-photonphysics

Thesis: The Opacity of the Universe for high and very high energy γ-rays
http://inspirehep.net/record/1254304/files/desy-thesis-13-033.pdf

MinutePhysics is on twitter - @minutephysics
And facebook - http://facebook.com/minutephysics
And Google+ (does anyone use this any more?) - http://bit.ly/qzEwc6

Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute!

Created by Henry Reich
...
https://www.youtube.com/watch?v=Fv1JJ227CQk