Evolution of quantum strategies on a small-world network

Abstract

In this paper, quantum strategies are introduced within evolutionary games in order to inves- tigate the evolution of quantum strategies on a small-world network. Initially, certain quantum strategies are taken from the full quantum space at random and assigned to the agents who occupy the nodes of the network. Then, they play n-person quantum games with their neighbors according to the physical model of a quantum game. After the games are repeated a large number of times, a quantum strategy becomes the dominant strategy in the population, which is played by the majority of agents. However, if the number of strategies is increased, while the total number of agents remains constant, the dominant strategy almost disappears in the population because of an adverse environment, such as low fractions of agents with dif- ferent strategies. On the contrary, if the total number of agents rises with the increase of the number of strategies, the dominant strategy re-emerges in the population. In addition, from results of the evolution, it can be found that the fractions of agents with the dominant strategy in the population decrease with the increase of the number of agents n in a n-person game independent of which game is employed. If both classical and quantum strategies evolve on the network, a quantum strategy can outperform the classical ones and prevail in the population.