Recently, leveraging the rich data from the 500-meter Aperture Spherical Radio Telescope (FAST), often dubbed as the "Chinese Sky Eye," a research team led by Dr. Li Di from the National Astronomical Observatory of China proposed a novel analytical framework called the "Pincus-Lyapunov Phase Diagram." This framework enables the quantification of the randomness and chaos of burst events, revealing the distinct temporal-energy behavior of Fast Radio Bursts (FRBs) compared to phenomena like earthquakes and solar flares. Such disparities challenge the stellar-origin hypothesis of FRBs.
On April 12th, this research was published as the cover article in Science Bulletin.
FRBs, brief and intense bursts of radio waves from the depths of the cosmos, release enormous energy within a fraction of a second, sufficient to power human civilization for trillions of years. Since their discovery in 2007, FRBs have captivated scientists worldwide due to their mystery and immense power. However, the origin of these powerful emissions remains unknown, and unraveling such a puzzle could lead to significant breakthroughs in astronomy and fundamental physics.
In their latest paper, the research team focused on the unpredictable and seemingly chaotic energy release processes, such as stellar flares and earthquakes. Dense celestial bodies, particularly magnetars with extreme magnetic fields, are hypothesized as potential triggers for FRBs through "stellar flares." Unlike earthquakes, whose timing and energy are not entirely random, previous periodic searches failed to reveal the correlation between the two fundamental physical parameters: time and energy.
Events like coin flips, characterized by randomness, exhibit stable unpredictability. We cannot predict the outcome of the next or subsequent flips based on the current result. In contrast, chaotic systems, which appear disorderly like random processes, become increasingly unpredictable over time. For example, while we can predict the weather a second from now by looking up at the sky, even the most advanced forecasting systems struggle to accurately predict weather weeks or months ahead. The longer the time span, the higher the uncertainty, a hallmark of chaotic systems.
Based on the novel phase diagram, the research team found that FRBs traverse a space of time-energy duality akin to Brownian motion, demonstrating a high degree of randomness. In contrast, earthquakes and solar flares, similarly unpredictable, exhibit significantly more chaos. They suggest that the high randomness of FRBs may arise from a combination of multiple mechanisms or emission locations.
The image portrays an artistic rendition of Fast Radio Bursts (FRBs) occurring on the surface of a magnetar. Cone-shaped spikes represent multiple eruptions of FRBs, varying in size to reflect differences in eruption energy. These spikes are connected by green line segments, forming a random walk path symbolizing the stochastic nature of FRB eruptions. Image courtesy of the research team.
Regarding this research, Dr. Bing Zhang, a theoretical expert in the field of FRBs and a professor at the University of Nevada, USA, remarked: "This innovative approach prompts theorists to delve deeper into the physical mechanisms of these eruptions, thus further applying it to the vast data sets from FAST to test the universality of the revealed physical laws."
The research team believes that the formidable observational capabilities of China's Five-hundred-meter Aperture Spherical radio Telescope (FAST), combined with innovative analysis methods, can deeply characterize the mysterious burst signals in the cosmos, potentially unveiling their origins.
For more information, refer to the related paper: https://doi.org/10.1016/j.scib.2024.02.010
