Randomness and Bell's Inequality [Audio only] | Two Minute Papers #31

TL;DR

Randomness in quantum mechanics is not due to hidden variables and cannot be predicted by any theory.

Transcript

Dear Fellow Scholars, this is Two Minute Papers with Károly Zsolnai-Fehér. When using cryptography, we'd like to safely communicate over the internet in the presence of third parties. To be able to do this, and many other important applications, we need random numbers. But what does it exactly mean that something is random? Randomness is the lack o... Read More

Key Insights

• ❓ Randomness is the absence of patterns and predictability.
• 🦾 Quantum mechanics exhibits behaviors that seem random but may have hidden variables.
• 🦾 Knowledge gaps contribute to the perception of randomness in quantum mechanics.

Questions & Answers

Q: Why are coinflips not strictly random?

Coinflips are not strictly random because if we possess complete knowledge of the forces acting upon the coin, such as its initial conditions and the physicist's modeling ability, we can predict the outcome.

Q: Can random numbers generated by computers be truly random?

No, random numbers generated by computers are not truly random because if we know the program code that generates them, they become predictable and non-random.

Q: How are atmospheric noise-generated random numbers used for encryption?

Atmospheric noise-generated random numbers are used for encryption because it is virtually impossible for an attacker to model the physics and initial conditions of every lightning strike, ensuring secure communication.

Q: Why is it difficult to determine if quantum mechanics is completely random?

It is difficult to determine if quantum mechanics is completely random because the behavior observed in quantum phenomena cannot be explained or predicted by any theory, suggesting that it is randomness rather than a result of hidden variables.

Summary & Key Takeaways

• Randomness is the lack of patterns and predictability, but various events considered random may actually have hidden variables responsible for their behavior.

• In quantum mechanics, certain behaviors appear completely random because our knowledge is insufficient to explain them, and they cannot be predicted by any theory.

• Bell's theorem proves that no physical theory of local hidden variables can replicate the predictions of quantum mechanics, confirming the randomness of quantum phenomena.