Quantum Information Processing, Vol. 5, No. 1, February 2006 (© 2006)
How Well Do People Play a Quantum Prisoner’s
and Tad Hogg
Received November 1, 2005; accepted January 11, 2006
Game theory suggests quantum information processing technologies could provide
useful new economic mechanisms. For example, using shared entangled quantum
states can alter incentives so as to reduce the free-rider problem inherent in eco-
nomic contexts such as public goods provisioning. However, game theory assumes
players understand fully the consequences of manipulating quantum states and are
rational. Its predictions do not always describe human behavior accurately. To
evaluate the potential practicality of quantum economic mechanisms, we experi-
mentally tested how people play the quantum version of the prisoner’s dilemma
game in a laboratory setting using a simulated version of the underlying quan-
tum physics. Even without formal training in quantum mechanics, people nearly
achieve the payoffs theory predicts, but do not use mixed-strategy Nash equilibria
predicted by game theory. Moreover, this correspondence with game theory for the
quantum game is closer than that of the classical game.
KEY WORDS: Quantum economic mechanisms; prisoner’s dilemma; free-
riding; experimental economics.
PACS: 03.67.-a; 02.50.Le; 89.65.Gh.
Recent developments in quantum computing and demonstrated
exchanges of entangled quantum states over distances of tens of kilome-
ters have led to increased interests in quantum games. Extending classi-
cal games into the quantum realm broadens the range of strategies.
Examples of quantum games analyzed with game theory methods include
the prisoner’s dilemma
and the n-player minority game.
direct relevance for economics are games involving correlated choices with-
Hewlett Packard Labs,1501 Page Mill Road, Palo Alto, CA 94304, USA.
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