DARK MATTER researchers may be on the cusp of a major breakthrough in the hunt for the universe’s most elusive substance.
Dark matter accounts for about 27 percent of everything in the universe, and yet, scientists have never observed or detected it. Scientists know dark matter exists because they can observe the gravitational effects it has on spinning galaxies, but its detection has so far escaped the world’s most sensitive instruments. But this could all change thanks to a team of researchers who have created a quantum crystal capable of detecting the weakest of electromagnetic fields.
The breakthrough could one day help scientists reveal the nature of dark matter and solve one of the biggest mysteries of the universe.
Researchers at the University of Colorado Boulder and the National Institute of Standards and Technology in the US created the quantum crystal by using magnetic fields to trap 150 charged particles or ions of beryllium.
The magnetic fields helped overcome the particles’ natural repulsion, allowing the ions to assembled into a structure twice as thick as a human hair.
The resulting arrangement resembled the form of a crystal and, most importantly, would vibrate when affected by an outside force.
Ana Maria Rey, a physicist at the JILA research institute in Colorado, told Live Science: “When you excite atoms, they don’t move individually. They move as a whole.”
The researchers believe the quantum crystal’s movements could be used to determine the strength of an electromagnetic field.
Many theories have been put forward about the nature of black matter, including theories about undetected black holes and gravity leaking from another dimension.
One of the most popular theories, however, is that dark matter is a yet-to-be-discovered particle and experiments at the Large Hadron Collider (LHC) in CERN are hoping to prove this.
But before the quantum crystal can be applied to the hunt for dark matter, the researchers had to overcome a major quirk of quantum mechanics.
According to the so-called Heisenberg uncertainty principle, scientists cannot precisely measure the position and momentum of particles.
The more accurately a particle’s position is measured, the less certainty there is about its momentum and vice versa.
The JILA scientists worked their way around this problem by using what they call quantum entanglement – a bizarre phenomenon in which the states of two or more objects are linked even if they are at opposite ends of the universe.
Professor Rey said: “By using entanglement, we can sense things that aren’t possible otherwise.”
The physicist and her colleagues entangled the motions of the beryllium particles with their spin.
Then, when the quantum crystal vibrated as a result of having an electromagnetic field passed through it, it would move a certain amount.
However, because of the uncertainty principle, trying to measure the displacement or how many of the beryllium particles were moved would produce a lot of quantum noise.
By entangling the particles’ spin, the scientists have been able to spread the noise out, allowing for measurements 10 times more precise than existing quantum sensors.
And Professor Rey and her team think they can make an even more sensitive detector.
But what does all of this mean for dark matter? According to one theory, dark matter may be explained through the discovery of axions – hypothetical elementary particles proposed in the late Seventies.
These theoretical particles could have the mass of a millionth or billionth of an electron, which could explain why they have eluded us for so long.
According to some predictions, axions may at times convert into photons.
If this is the case, the particles would no longer be “dark” but give off a faint electromagnetic field.
Should any axions fly through the quantum crystal detector, there is a chance scientists could detect their presence.
The results of the study were published this month in the journal Science.