https://www.sciencedaily.com/releases/2021/10/211015094809.htm

Parrondo's paradox is a phenomenon where the switching of two losing games results in a winning outcome. In the two-sided quantum coin tossing game introduced by the authors, they showed in a previous work that random and certain periodic tossing of two quantum coins can turn a quantum walker's expected position from a losing position into a fair and winning position, respectively. In such a game, the quantum walker is given a set of instructions on how to move depending on the outcome of the quantum coin toss.

Inspired by the underlying principles of this quantum game, Joel Lai, the lead author of the study from SUTD explained, "Suppose I present to you the outcome of the quantum walker at the end of 100 coin tosses, knowing the initial position, can you tell me the sequence of tosses that lead to this final outcome?" As it turns out, this task can either be very difficult or very easy. Lai added: "In the case of random switching, it is almost impossible to determine the sequence of tosses that lead to the end result. However, for periodic tossing, we could get the sequence of tosses rather easily, because a periodic sequence has structure and is deterministic."