From 0133c021a0fcd9d902f491afdacd906ca8b90978 Mon Sep 17 00:00:00 2001 From: Zachary Ratliff <90049582+zachratliff@users.noreply.github.com> Date: Sat, 20 Nov 2021 12:49:57 -0500 Subject: [PATCH] Update lec_19_quantum.md re-word --- lec_19_quantum.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lec_19_quantum.md b/lec_19_quantum.md index 2eb67f8..dad3dd7 100644 --- a/lec_19_quantum.md +++ b/lec_19_quantum.md @@ -90,7 +90,7 @@ Specifically, consider an event that can either occur or not (e.g. "detector num In classical probability, we model this by a probability distribution over the two outcomes: a pair of non-negative numbers $p$ and $q$ such that $p+q=1$, where $p$ corresponds to the probability that the event occurs and $q$ corresponds to the probability that the event does not occur. In quantum mechanics, we model this also by pair of numbers, which we call _amplitudes_. This is a pair of (potentially negative or even complex) numbers $\alpha$ and $\beta$ such that $|\alpha|^2 + |\beta|^2 =1$. The probability that the event occurs is $|\alpha|^2$ and the probability that it does not occur is $|\beta|^2$. -In isolation, these negative or complex numbers don't matter much, since we anyway square them to obtain probabilities. +In isolation, these negative or complex numbers don't matter much, since we square them anyway to obtain probabilities. But the interaction of positive and negative amplitudes can result in surprising _cancellations_ where somehow combining two scenarios where an event happens with positive probability results in a scenario where it never does. ::: { .pause }