A Life in the Day: e-sports, badminton and WIMPS
Dr Amruth Alfred’s days have changed drastically in the last couple of years. So have the nights.
“During the first years of my PhD, I used to wake up around noon or 1 p.m., skipping breakfast and having lunch at HKU canteens with friends. My day typically started at 3–4 p.m. with work involving computer simulations and data from telescopes. I was also a professional e-sports player, so evenings included practice, followed by dinner at 9 p.m. I stayed in the office until midnight, then played video games with my girlfriend until 3–4 a.m. We'd go to McDonald's for breakfast, have deep conversations with friends there, and then I'd get to bed around 7 a.m. This routine was regular until two years ago,” Alfred told us.
It was two years ago that he took up badminton. He then changed from being a night owl to getting up (almost) with the larks. “These two years have been increasingly physical. I've been working on becoming much healthier and have improved my diet. I just did a body scan, and in these two years, I’ve lost 8% of my body fat.”
Another change has been the completion of his PhD and graduation. So he is now Dr Alfred. “I've started as a postdoctoral fellow at Hong Kong University, continuing my work with our group,” he said, “though actually the work hasn’t changed as a result.”
But what has really changed his work was the appearance of his article on the front cover of Nature Astronomy in June 2023, under the title “Dark matter under the lens.” The striking cover illustration is his own, based on images from his research.
“When you get accepted in Nature Astronomy, you need to submit suggestions for the cover. Every author needs to submit something. And then I spent days and nights creating my cover artwork. I created eight different images and sent all of them in. And they finally picked one,” he told us. “I think I worked harder on the cover than on my research,” he added with a smile.
It turns out that a good image is important for the journal, and being on the cover gets your work noticed. “People see that you were featured on the cover, and they pay more attention, even though it may not mean that that article is scientifically better than the other articles that have been published.”
“Last year I was involved in many competitions and entered for many awards because of this publication. I won the Hong Kong Young Scientist Award, which is given to the best PhD research in Hong Kong within physics, maths, and chemistry,” he told us. Then he added, modestly, “I'm pretty sure I got it just because it was on the cover. Because the other competitors had Nature publications as well.”
Another thing that’s changing is Alfred’s area of research, dark matter. This mysterious substance is believed to make up 85 percent of the universe, but we don’t know what it is.
Dark matter is best studied via a technique called gravitational lensing, Alfred told us. This involves observing how much the light from distant galaxies (or any massive object) might be warped or distorted by dark matter. This allows for a kind of reverse engineering of what is doing the warping. The theory that’s been dominant for decades is that dark matter is made up of very heavy particles (up to a few hundred times as massive as a proton), known as weakly interacting massive particles, or WIMPS. This would account for the huge mass of dark matter. However, no sign of these particles has been detected in any lab. Moreover, assuming the existence of WIMPS in the current models does not explain a range of astronomical observations that have been made, including those pertaining to gravitational lensing.
“This is known as the lensing anomaly problem,” Alfred said.
A newer alternative theory says that dark matter might be made up of very light particles that behave like waves, called axions.
Alfred’s team ran the model on the assumption that these lighter particles were causing the warping. The results were unexpected. “What we found with our research is that when you adopt ultra-light dark matter (axions) in your model, you can actually reproduce the same results as the observations, apparently solving the two-decade-long lensing anomaly problem. We didn’t set out with this expectation, but the experiment seems to suggest that the axions/wave theory may have more going for it. So, we may be on the cusp of a change.” The old theory has not been given up on, but to quote Nature back in 2020, we might be approaching the “last chance for WIMPS.”
We asked Alfred what got him into science. Books by two of his heroes, Arthur C Clarke and Carl Sagan (he likes to give the latter’s Cosmos as a gift to friends), were influential. But so was his upbringing in Sri Lanka. “Where I grew up, it’s quite rural. Every night, you can see the sky filled with stars and planets. It made me wonder, what’s going on up there?”
“But also, my parents supported me. They gave me a lot of books on physics and biology, about nature and the universe. I read all of them and remembered all the cool trivia and facts. My reading made me so curious to know why something happens, why these things happen, no matter the field.”
Still consumed by the same curiosity, Alfred and his supervisor, Dr Jeremy Lim, will be hosting a conference in Hong Kong supported by Croucher Foundation early in 2025. Its title?
“Dark Matter under the Gravitational Lens.”