麻豆传媒

Editorial: 鈥�鈥楤oring鈥� Higgs has powers we never dreamed of鈥�

THE Higgs boson may have the right mass to wreck the universe 鈥� hurray! Death by Higgs is the simplest way to do away with a paradoxical menagerie of disembodied intelligent beings that shouldn鈥檛 exist, yet remain in the best cosmological models.

What鈥檚 more, the end is a comfy 20 or 30 billion years off. 鈥淭hat鈥檚 quite a few billion; it鈥檚 not like we should rush out and buy life insurance,鈥� says at the California Institute of Technology in Pasadena, who put forward the idea along with , also at Caltech.

鈥淭hat鈥檚 quite a few billion years away 鈥� it鈥檚 not like we should rush out and buy life insurance鈥�

The paradox arose a decade or so ago, when physicists realised their models led to a future filled with Boltzmann brains: fully formed conscious entities that pop out of the vacuum. It sounds bizarre, but there鈥檚 nothing to stop matter sometimes randomly arranging itself in just the right way for this to occur. The problem arises when you add in the universe鈥檚 accelerating expansion.

This provides limitless time, space and energy for Boltzmann brains to form, even after life as we know it has winked out, causing them to eventually outnumber ordinary consciousnesses. But that would make the brains鈥� experience of the universe more typical than ours, which is a problem as our understanding of the cosmos assumes that we are typical observers.

Theories have been proposed in which the universe ends before the brains take over, solving the paradox, but these are mostly based on untested physics like string theory. By contrast, the Higgs boson can do it using well-accepted physics.

For this to work, the Higgs boson鈥檚 accompanying field must be metastable, meaning it can spontaneously settle down into a lower energy state. A bubble of space would then sprout up, with its own physical laws, and expand at the speed of light to destroy everything in its path, including the universe as we know it.

The idea isn鈥檛 new, but now that the Higgs has been found, we have a measurement of its mass: about 125 gigaelectronvolts. Carroll and Boddy combined that value with the , and calculated that physical laws favour a metastable Higgs over a stable one ().

That sounds promising, but the metastable Higgs looks only a tad more likely. New measurements of the top quark鈥檚 mass are expected in 2015, when the Large Hadron Collider switches on after a two-year rest, and they could make a stable Higgs field more likely.

The new data should also help to pin down another unknown. If the Higgs field is metastable and flips into a lower energy state, will the affected regions grow faster than the universe is expanding? If yes, the Higgs field will destroy the universe and the Boltzmann brain paradox is resolved.

Even if not, the field may yet be able to destroy the universe. But whether it will in this scenario can only be resolved via a thorny problem related to the nature of probability in multiple universes. Anyone wanting a swift answer to Boltzmann brains will be hoping we don鈥檛 have to go there.

This article appeared in print under the headline 鈥淒eath by Higgs rids us of cosmic brains鈥�