00770nas a2200145   4500000000100000008004100001260000600042100001300048700002200061700001300083245005100096300001500147490000700162520045500169       2007                            d  c91 aJ. Kosik1 aJaroslaw Miszczak1 aV. Buzek00aQuantum Parrondo's game with random strategies  a2275–2280 v543 aWe present a quantum implementation of Parrondo's game with randomly switched strategies using (1) a quantum walk as a source of 'randomness' and (2) a completely positive (CP) map as a randomized evolution. The game exhibits the same paradox as in the classical setting where a combination of two losing strategies might result in a winning strategy. We show that the CP-map scheme leads to significantly lower net gain than the quantum-walk scheme.