Persi Warren Diaconis (/ˌdaɪəˈkoʊnɪs/; born January 31, 1945) is an American mathematician of Greek descent and former professional magician.

[8] According to Martin Gardner, at school, Diaconis supported himself by playing poker on ships between New York and South America.

In 1990, he published (with Dave Bayer) a paper entitled "Trailing the Dovetail Shuffle to Its Lair"[11] (a term coined by magician Charles Jordan in the early 1900s) which established rigorous results on how many times a deck of playing cards must be riffle shuffled before it can be considered random according to the mathematical measure total variation distance.

Among other things, they showed that the separation distance of an ordered blackjack deck (that is, aces on top, followed by 2's, followed by 3's, etc.)

[13][14] Diaconis has been hired by casino executives to search for subtle flaws in their automatic card shuffling machines.