AN unlimited source of energy may one day be available if physicists can make tiny clumps of particles called Q-balls, say physicists at CERN, the European centre for particle physics near Geneva. The exotic Q-balls would also make it possible to explore a new world of physics.
Q-balls are a consequence of the theory of supersymmetry, which would help to unify all the forces in nature. The theory requires each particle of matter we know of to have an as yet undetected partner, with quarks teamed up with 鈥渟quarks鈥� and electrons paired with 鈥渟electrons鈥�, for instance.
Forces between supersymmetric particles would glue them together in much the same way that quarks are glued together to produce the protons and neutrons that make up atomic nuclei. 鈥淚nstead of an atomic nucleus, however, the result is a Q-ball,鈥� says Alex Kusenko of CERN. With his colleagues, he has calculated some of the strange physical properties of Q-balls.
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In the familiar world, matter groups neatly into small particles, like protons and atoms, to obey the laws of quantum mechanics. These say that normal particles, which have an intrinsic angular momentum, cannot exist in a single quantum state. But because supersymmetric particles carry zero spin, it turns out that this rule no longer holds. 鈥淭here is no limit to the size of a Q-ball-it can be as small as a nucleus or as big as a star,鈥� says Kusenko.
More importantly, Kusenko says that inside the supersymmetric clump, the various forces would be entirely different from those in our Universe. 鈥淎 Q-ball is essentially a new universe in a nutshell,鈥� says Kusenko. 鈥淚nside, forces like the strong nuclear force may be turned off and new forces that are not evident in our Universe turned on.鈥� The bigger the Q-ball, he says, the more the laws of physics within it will diverge from those we know.
Kusenko鈥檚 team proposes exploring ultra-high-energy physics by feeding normal particles into a Q-ball where the laws of physics could be similar to those in the energetic early Universe. Firing normal particles into a 1-gram Q-ball made of squarks and selectrons could reveal physics at energies of about 100 million gigaelectronvolts, 100 000 times what is currently achievable, they say. They have submitted their theory to the journal Physical Review B.
Q-balls could also have far-reaching practical applications. 鈥淭hey could be used to provide an inexhaustible source of cheap energy,鈥� says Kusenko. He envisages squirting protons-which normally do not decay-into a Q-ball. 鈥淎lmost any new physics imaginable causes proton decay,鈥� says Kusenko. 鈥淪uch decays unleash the tremendous energy binding the quarks together-weight for weight, almost a hundred times the energy liberated by a hydrogen bomb.鈥�
He suggests the energy could be extracted by placing the Q-ball in water, so that proton decay fragments-electrons and photons-emerging from the ball would heat the water.
All this assumes of course that supersymmetric particles exist. Whether they do or not may become clear when the next generation of particle accelerators is running. Even if they do, the idea may be impractical, Kusenko admits. 鈥淲e might be able to create supersymmetric particles but still face technical problems in fabricating Q-balls.鈥�
