Quantum Hide-and-Seek

Quarks misbehaving. In "Quantum Focus," players try to corral three quarks, whose positions can range from known but separate (left) to unknown but overlapping (right).

Caution! Objects on screen may not be exactly where they appear--at least not in "Quantum Focus," a game that aims to make child's play of quantum mechanics.

The game's designer, Tarun Biswas, a physicist at the State University of New York, New Paltz, thinks that overtly educational computer programs for kids don't work. Games are the way to children's minds, says Biswas, who used to design teaching software. And just as children get a feel for classical mechanics by playing ball, Biswas hopes they can get a feel for quantum mechanics by playing with quantum objects.

In Quantum Focus, three quarks--red, blue, and green--are hidden. Players see colored squares that indicate the chance that a quark is present in a particular spot. An intermediate color, such as magenta, suggests that two quarks might be in the same place. If a player clicks on the square where the quark is, it appears for a while and stays still. The goal is to catch all three quarks in the same spot.

The quarks move as if they were all connected at a central point by invisible springs, just as they would behave within a particle like a proton. But in the probabilistic quantum world, particles on springs behave differently than you would expect, spending most of their time at the extreme edges of their range rather than in the center. In the macroscopic world, the closest analogy is the way a pendulum races through the center but slows down at the turning point of each swing. A time-lapse photo would show that the pendulum spends most of its time at the turning points. Biswas describes the game in a paper posted on the arXiv preprint server.

"This game has the rules of the real universe--but it's a part of the universe you never see," says Richard Halpern, a colleague of Biswas's at SUNY New Paltz. The uncanny drift of quarks does give a feel for the quantum world, but winning isn't easy. Says Halpern, "I don't score too high!"

Related Sites
Tarun Biswas's Web site ("Quantum Focus" can be downloaded for free)

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