Negative probabilities - can they be real???

Recently, I have been hearing talk of negative probabilities. But what does this even mean? Are they a real thing? In this video, I look at one way in which negative probabilities can appear in quantum theory. Well, maybe they can... 00:00 Intro 00:22 Negative probabilities? 05:30 Polarizing filters 07:43 What even is light? 09:48 An interesting experiment 13:59 Entanglement 15:09 Alice and Bob 17:42 Interpretation 22:41 Now what?