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Awaiting a messenger from the multiverse

点击量:   时间:2019-03-14 09:16:01

By Stephen Battersby AT THE most powerful particle accelerator in the world, the twin colliding beams of protons have been switched off for a few hours. All seems quiet, but both the giant machine and the foundations of physics are about to be shaken by a tiny time bomb. Hiding within a copper plate deep inside one of the accelerator’s massive detectors is a peculiar interloper: a particle that is waiting to explode, and with its incandescent fragments write a message from beyond our universe. If this particle does appear at the Large Hadron Collider (LHC) near Geneva, Switzerland, it could change the nature of physics. Physicists might have to abandon their goal of explaining the fundamental basis of our reality and just accept that the properties of matter and energy in our universe arose at random. It could mean not only that we live on a small planet in an insignificant solar system in one of a trillion galaxies in the universe, but our own universe is just one insignificant slice of an unimaginably vast and diverse multiverse. To many physicists, that is anathema; but not to Savas Dimopoulos of Stanford University in California or his colleague Nima Arkani-Hamed at Harvard University. In 2002, they first began to wonder what a multiverse might mean for particle physics. This was at a time when the multiverse was being discussed, albeit reluctantly, as a solution to a cosmic problem. Astronomers had discovered a repulsive force pushing the galaxies apart, caused by an inherent energy present in space. Often called the cosmological constant,