Quantum Nash Equilibrium Research Articles

Nonlinear dynamics of a heterogeneous quantum Commons’ tragedy

This paper first builds a nonlinear dynamic system of the Commons’ tragedy with quantum strategies in discrete time. There are two heterogeneous expectations in the game, namely, one of the two players is boundedly rational and the other is of adaptive expectation. Secondly, we obtain a sufficient and necessary condition for quantum Nash equilibria to be stable equilibria. Finally, we investigate the impacts of quantum entanglement on the stable region of systems and analyze the behaviors of complex dynamical systems. The results show that quantum Nash equilibria are stable points of nonlinear dynamics for quantum Commons’ tragedy if both quantum entanglement and quantum strategy adjustment speed satisfy certain conditions. In addition, numerical simulations discuss the features of nonlinear dynamics, such as bifurcation, the largest Lyapunov exponent, fractal dimension, strange attractor, and sensitivity to initial conditions. The numerical results show that nonlinear dynamics appear chaotic if the adjustment speed of quantum strategy or the quantum entanglement degree is larger.

The chaotic dynamics of a quantum Cournot duopoly game with bounded rationality

This paper analyzes the chaotic dynamics of a quantum Cournot duopoly game with bounded rational players by applying quantum game theory. We investigate the impact of quantum entanglement on the stability of the quantum Nash equilibrium points and chaotic dynamics behaviors of the system. The result shows that the stability region decreases with the quantum entanglement increasing. The adjustment speeds of bounded rational players can lead to chaotic behaviors, and quantum entanglement accelerates the bifurcation and chaos of the system. Numerical simulations demonstrate the chaotic features via stability region, bifurcation, largest Lyapunov exponent, strange attractors, sensitivity to initial conditions and fractal dimensions.

Quantum Nash equilibrium in the thermodynamic limit

The quantum Nash equilibrium in the thermodynamic limit is studied for games like quantum Prisoner’s dilemma and quantum game of Chicken. A phase transition is seen in both games as function of the entanglement in the game. We observe that for maximal entanglement irrespective of the classical payoffs, majority of players choose quantum strategy over defect in the thermodynamic limit.

Decision, Uncertainty and Cooperation: A Behavioral Interpretation Based on Quantum Strategy

This paper presents a new attempt to explore people’s cooperative behavior under the natural uncertainty in decision making process. The most recent development of quantum cognition creatively enriched the exploration to the endogenous uncertainty in human behavior by expanding the strategic space. In this paper we extend the quantum decision-making model to a two-player Prisoner’s dilemma game by bringing in the evolutional decision operators with quantum phases. These quantum phases, following uniform random distribution when the decisions are confined to individual decision-making process, will change according to the different levels of implied cooperative inclination, and lead to possible new Nash Equilibriums that emerge from a “hyper” decision space. We also bring in the Dissimilarity Index from complex network literature, to capture and measure the cooperative inclination between the players. Conditions of Quantum Nash Equilibrium are derived out from dynamic quantum equations under the Heisenberg Picture.

Quantum game theory based on the Schmidt decomposition

We present a novel formulation of quantum game theory based on the Schmidt decomposition, which has the merit that the entanglement of quantum strategies is manifestly quantified. We apply this formulation to 2-player, 2-strategy symmetric games and obtain a complete set of quantum Nash equilibria. Apart from those available with the maximal entanglement, these quantum Nash equilibria are extensions of the Nash equilibria in classical game theory. The phase structure of the equilibria is determined for all values of entanglement, and thereby the possibility of resolving the dilemmas by entanglement in the game of Chicken, the Battle of the Sexes, the Prisoners' Dilemma, and the Stag Hunt, is examined. We find that entanglement transforms these dilemmas with each other but cannot resolve them, except in the Stag Hunt game where the dilemma can be alleviated to a certain degree.

Appropriate quantization of asymmetric games with continuous strategies

We establish a new quantization scheme to study the asymmetric Bertrand duopoly with differentiated products. This scheme is more efficient than the previous symmetric one because it can exactly make the optimal cooperative payoffs at quantum Nash equilibrium. It is also a necessary condition for general asymmetric games with continuous strategies to reach such payoffs.