Science & Technology, Australia (Commonwealth Union) – UNSW quantum engineers have developed a groundbreaking amplifier that could assist other scientists in the search for elusive dark matter particles.
The engineers put across a case scenario of throwing a ball. Where in general, we would expect science to determine its exact speed and location at any given moment.
They pointed out however, that the theory of quantum mechanics states that you cannot know both with infinite precision simultaneously.
The more precisely you measure the ball’s position, the less accurately you can determine its speed.
This phenomenon is known as Heisenberg’s uncertainty principle, named after the renowned physicist Werner Heisenberg who first articulated it.
Researchers of the study highlighted the fact that for a ball, this effect is negligible, but in the quantum realm of tiny electrons and photons, measurement uncertainty becomes extremely important.
This challenge is being tackled by a team of engineers at the UNSW, who have developed an amplifying device that performs precise measurements of very weak microwave signals through a process called squeezing.
It was pointed out that squeezing involves bringing down the certainty of one property of a signal to get an ultra-precise measurement for another property.
The research team at UNSW, led by Associate Professor Jarryd Pla, has significantly increased the precise nature of measuring signals at microwave frequencies, such as those emitted by mobile phones, making a new world record in the process.
The precision of measuring any signal is fundamentally limited by noise, the fuzziness that obscures signals. This is something we may have experienced if we have ever attempted to venture out of range when listening to AM or FM radio, according to the researchers.
In the quantum world, uncertainty imposes a limit on how much noise can be reduced in a measurement.
Associate Professor Pla from the UNSW, School of Electrical Engineering and Telecommunications and co-author of the paper that appeared in Nature Communications pointed out that even in a vacuum, a space devoid of everything, the uncertainty principle dictates that there must still be noise. This is referred to as ‘vacuum noise.’ For many quantum experiments, vacuum noise is the dominant effect that hinders us from making more accurate measurements.
What was significant is that the squeezer put together by the UNSW team has the ability to beat this quantum limit.
“The device amplifies noise in one direction, so that noise in another direction is significantly reduced, or ‘squeezed’. Think of the noise as a tennis ball, if we stretch it vertically, then it must reduce along the horizontal to maintain its volume. We can then use the reduced part of the noise to do more precise measurements,” explained Associate Professor Pla.
The device emerged from meticulous effort. PhD candidate Arjen Vaartjes, who co-authored the paper with UNSW colleagues Dr. Anders Kringhøj and Dr. Wyatt Vine, indicated that achieving squeezing at microwave frequencies is extremely challenging because the materials typically destroy the delicate squeezed noise and they have undertaken extensive engineering to eliminate sources of loss, using high-quality superconducting materials to construct the amplifier.
The team holds the view that the new device could accelerate the search for axions, which are currently only theoretical particles but are proposed by many scientists as a key component of the mysterious dark matter.
Making of accurate measurements is crucial for scientists trying to uncover the nature of dark matter, which is thought to comprise about 27 percent of the known universe. Despite its significant presence, dark matter remains a cosmic mystery because scientists have not yet been able to identify it.
Researchers of the study highlighted the facts that as the name suggests, dark matter neither emits nor absorbs light, making it ‘invisible.’ However, physicists are confident it exists due to the gravitational forces it exerts, which prevent galaxies from flying apart.
There are many theories about the composition of dark matter, which consist of the proposed existence for axions.
“What we also showed in our study is that the device can be operated at higher temperatures than previous squeezers and also in large magnetic fields,” said Dr Vine.
“This opens the door to applying it in techniques like spectroscopy, which is used to study the structure of new materials and biological systems such as proteins. The squeezed noise means you could study smaller volumes or measure samples with greater precision.”
