Feynman's Infinite Quantum Paths

Viewers like you help make PBS (Thank you 😃) . Support your local PBS Member Station here

How to predict the path of a quantum particle. Part 3 in our Quantum Field Theory Series.

You can further support us on Patreon at

Get your own Space Time t­shirt at

Tweet at us! @pbsspacetime

Facebook: facebook.com/pbsspacetime

Email us! pbsspacetime [at] gmail [dot] com

Comment on Reddit

Help translate our videos!

Previous Episode:

The First Quantum Field Theory

There is a fundamental limit to the knowability of the universe. The Heisenberg uncertainty principle tells us that the more precisely we try to define one property, the less definable is its counterpart. Knowing a particle’s location perfectly means its velocity is unknowable. But unmeasured properties are not just uncertain; they are undefined. Quantum mechanics seems to imply that ALL possible properties, paths, or events that could reasonably occur between measurements DO occur. Whether or not this is true, a mathematical description of this crazy idea led to the most powerful expression of quantum mechanics ever devised: Richard Feynman’s path integral formulation.

Written and Hosted by Matt O’Dowd

Produced by Rusty Ward

Graphics by Kurt Ross

Made by Kornhaber Brown (www.kornhaberbrown.com)

Comments answer by Matt:

Satya Prakash

Jakub Mintal

The EEZZ

Lazarus The adventurer

ForTiorI

Special thanks to our Patreon Big Bang, Quasar and Hypernova Supporters:

Big Bang

CoolAsCats

Shane Robinson

David Nicklas

Eugene Lawson

Joshua Davis

Quasar

Tambe Barsbay

Max Levine

Mayank M. Mehrota

Mars Yentur

Hypernova

Chuck Zegar

Jordan Young

Ratfeast

John Hofmann

Joseph Salomone

Martha Hunt

Craig Peterson

Prof. Dr. Kenneth Michael Beck