(Non-)Locality, the Einstein-Podolsky-Rosen argument, and Bell's inequality
Channel: Ian Jauslin
Date: 2022-11-04

In this video, I discuss how the winners of the 2022 Nobel Prize in physics have shown that the world is NOT LOCAL. This means that, at least in principle, it is possible for an action taken somewhere on Earth to have an effect arbitrarily far away, even in the most remote corners of the universe. The Nobel Prize winners achieved this by proving that an inequality, called Bell's inequality, is violated in nature. In this video, I describe the argument made by John Bell that a violation of Bell's inequality implies that there is no locality. This argument starts from the Einstein-Podolsky-Rosen "paradox" (EPR), which I describe as well.

Followup video: A Proof of Bell's inequality (difficulty 3/4): https://youtu.be/hZX7wUdFSOQ

This video was filmed at the Department of Mathematics, Rutgers University in Piscataway, NJ, on October 29, 2022.

Very special thanks go to Sasha Pohle for helping me produce this video, as well as to Sheldon Goldstein, Michael Kiessling, Lawrence Frolov, Andreas, Hans, Lucy and Tania Jauslin, and Shadi Tahvildar-Zadeh for their useful feedback and comments.

Photo credits:
  A. Einstein: AIP Emilio Segrè Visual Archives, W. F. Meggers Gallery of Nobel Laureates Collection
  B. Podolsky: AIP Emilio Segrè Visual Archives, Physics Today Collection
  N. Rosen: AIP Emilio Segrè Visual Archives, Physics Today Collection
  J. Bell: CERN
  A. Aspect: Ecole polytechnique Université Paris-Saclay
  J. Clauser: AIP Emilio Segrè Visual Archives, Gift of John Clauser
  A. Zeilinger: Jaqueline Godany

00:00 Introduction
00:47 Locality
04:01 The EPR "paradox"
12:03 Bell's inequality
15:13 Comments
17:28 Conclusion