The blog of Xeno, a slightly mad scientist
A Canadian scientist at the forefront of research on antimatter has proposed a novel way to solve one of the field’s most daunting problems — what to keep it in.
For experimental physicists, antimatter is an elusive quarry because it will vanish in a flash of light upon contact with anything made of regular matter. But a paper published Sunday points the way to a potential solution, in which lasers will literally freeze atoms of anti-hydrogen in place so they can be studied and compared to regular atoms.
The proposal by Makoto Fujiwara, a research scientist at Canada’s particle physics lab TRIUMF and an adjunct professor at the University of Calgary, has not been tested in reality, but computer simulations he devised with an American co-author indicate that a laser-based technique called Doppler cooling could chill anti-hydrogen to just a whisker above absolute zero.
At that point, he writes in the Journal of Physics B, it might be possible for scientists to determine the precise colour and weight of the strangest stuff in existence.
Much progress has recently been made in this effort, notably by Canadians working at the ALPHA project at CERN in Geneva, including Mr. Fujiwara, who in 2011 used magnets to hold particles of anti-hydrogen stable for as long as 15 minutes, and last year made the first ever direct measurement of antimatter’s energy.
And just last month, Mr. Fujiwara’s colleagues in B.C. started to test a prototype of his laser cooling system. But antimatter remains one of the great mysteries in science, predicted in theory in 1930, discovered three years later, and still as baffling as anything in science.
Antimatter is just as it sounds, the opposite of matter, and when a particle meets its antiparticle, they both vanish in a flash of light. The big question is why there is so little antimatter around, and a surplus of regular matter.
Theory says both were created in equal parts during the Big Bang, and indeed the lingering flash of their mutual annihilation can still be detected in the universe. But for some reason regular matter eventually won out, and today antimatter is exceedingly rare. Other than in radioactive decay or cosmic ray collisions, it is not naturally produced, and man-made production is still small scale, although it is widely used in medicine for PET (positron emission tomography) scanning.
We want anti-hydrogen atoms as cold as possible in our trap, and by cold I mean not moving
Discovering any difference between hydrogen and antihydrogen, therefore, might mean discovering the reason why there is any stuff at all, and why the universe is not just a big flash of light with nothing left over. On the other hand, proving that antihydrogen really is the exact opposite of the regular kind would be an important foundation on which to build future experiments.
And so, with this latest theoretical proof of the laser cooling concept, the effort turns to actually building a machine that can do it.
Already, the ALPHA apparatus at CERN in Geneva is capable of trapping a cloud of antihydrogen inside a cucumber-sized cylinder surrounded by superconducting magnets and silicon detectors. The next step is to cool it.
“We want anti-hydrogen atoms as cold as possible in our trap, and by cold I mean not moving. In particular, to measure the gravitational properties, antihydrogen in our trap is still moving way too fast. So this paper has shown that the technique called laser cooling can be applied in our experimental set-up,” Mr. Fujiwara said. …
We still don’t know if gravity attracts or repels antimatter. In other words, it might fall up! And that may explain some things we don’t understand about the shape of the universe.
While the overwhelming consensus among physicists is that antimatter will attract both matter and antimatter at the same rate that matter attracts matter, there is a strong desire to confirm this experimentally, since the hypothesis is still open to falsification. – wiki
I’d love it if antimatter provided some real anti-gravity. Inventing anti-gravity has been one of my life goals.
For now, you might want to enjoy an this fake magnetic anti-gravity platform:
Perhaps I’ll get a Fascinations Levitron Globe World Stage for my birthday tomorrow… instead of a Tesla Model S. ;-)