Khaberni - A team of scientists from Japan, Spain, and the United States used one of the world's fastest supercomputers, "Fugaku", to better understand the impact of dark energy throughout the universe.
During the experiment, the supercomputer, which uses more than 150,000 CPU cores to achieve more than 442 petaflops of computational power, conducted one of the largest cosmic simulations to date, allowing the scientist team to study the effects of changing dark energy over time on the evolution of the universe. Their research paper challenges the "Lambda" model of cold dark matter (ΛCDM), which assumes that the effects of dark energy remain constant, according to reports.
Dark energy is responsible for the accelerating expansion of the universe, however, this energy, which makes up about 70% of the universe, remains largely a mystery.
Scientists have long assumed that dark energy is a constant, unchanging entity, but recent data from the Dark Energy Spectroscopic Instrument (DESI) suggest another possibility.
What if dark energy is a property of the universe that varies over time?
The initial results from DESI, released in 2023, indicated that dark energy, in fact, weakens over time, meaning that it is not constant. This allowed for the emergence of universe models that include a type of dark energy that evolves over time - Dynamic Dark Energy (DDE)
Led by Associate Professor Tomoaki Ishiyama from Chiba University, the team set out to study the effect of DDE in different scenarios, using the power of "Fugaku". The simulations conducted by the team showed that while DDE has modest effects on its own, variations in parameters like matter density significantly affect galaxy formation and cosmic structure.
The team used "Fugaku" to perform three high-precision N-body simulations, each larger in size by eight times than previous studies.
The team's results showed that the impact of DDE itself is minimal on cosmic structure, however, the DESI-derived model, with increased matter density, showed significant effects.
According to the researchers, this model predicted an increase in massive galactic clusters by up to 70% in the early ages of the universe due to stronger gravitational forces, and more importantly, the researchers closely examined the predictions of the DDE model, demonstrating their compatibility with observational data from DESI. This reinforces the idea that dark energy is not constant.
Dr. Ishiyama explained in a press release: "In the near future, it is expected that large-scale galaxy surveys using the Subaru Prime Focus Spectrograph and DESI will significantly improve measurements of cosmic standards, and this study provides a theoretical basis for interpreting this future data".
Fugaku was the world's fastest supercomputer until it was surpassed by the American Frontier computer in 2022, and now, Japan is seeking to surpass Frontier, having invested $750 million to develop Fugaku Next. This next-generation supercomputer is designed to enhance artificial intelligence and scientific research in Japan.
The detailed study was published in the Physical Review D journal.
