Physics - Ch 66 Quantum Mechanics 2: Basic Concepts (1 of 38) What is Pair Production?

In this video I will explain and demonstrate mathematically why pair product cannot happen in empty space.

Next video in this series can be seen at:

[zakirhussain-jsku]

Particle moves as a particle-wave system. Wave is temporary in nature & lasts only during motion of particle. As soon as particle stops its motion its associated wave dissipates & disappears leaving the particle behind. Photon has to stop to change into particle. Since photon cannot stop in free space pair production cannot happen. Atom stops the photon allowing it to change back to particle.

[zakirhussain-jsku]

Photon emerging from annihilation of electron & positron. Electron & positron emerging from Photon. Gamma photon emerging from nucleus during fusion reaction. Are all particles made of same building blocks?

[rayanlotfi]

Why is the Lorentz factor used for energy?

[jumpieva]

so is it safe to say that a gamma ray 'entices' a nucleus to emit the pair, and not actually the gamma ray 'converting' ? also does the element matter, or does it just care about being a nucleus? i.e. shooting gamma rays near denser objects vs lighter, etc.

[DrDoom-kmhz]

Sir, Does this mean that an electron and positron cannot combine again to create a photon unless there is another heavy nucleus that gives the additional momentum to the electron positron pair to be able to create the original photon?

[davidsault]

An excellent verbal explanation of the mathematical argument. A joy to follow.

[satyamkumar]

Sir, how can we define positron in easy words??

[WelshGuitarDude]

Not sure you really explained pair production here only the math of it, not the logic of when or why it happens or its significance to quantum mechanics...at least you said it won't happen unless something happens to the photon but that was a bit vague for basic concept...

[richienkharbuli]

Sir, in this interaction does the photon need to strike the nucleus or is it sufficient for it to just be close to the nucleus in order for electron and positron to be produce?

[rah]

How is angular momentum conserved in pair production?

[RaccoonCity]

Hi, great video, as always ! I just have 1 question if you could answer I would really appreciate it. Are the electron and positron entangled ? Thanks !