When a leading mathematician shares a vision for future research, it captures the attention of the math community. This was the case in 1900 at the International Congress of Mathematicians in Paris. David Hilbert, a renowned mathematician, introduced ten unsolved problems that would shape the 20th century. Over time, he expanded this list to 23 problems, leaving a lasting impact on mathematical thought.
Among these was Hilbert’s sixth problem, which called for "axiomatizing" physics. This means establishing the fundamental mathematical principles underlying all physical theories. While it’s unclear whether mathematicians can ever fully accomplish this, researchers have worked diligently to take steps in that direction.
Recently, a paper by Yu Deng, Zaher Hani, and Xiao Ma from the University of Chicago and the University of Michigan emerged, claiming to tackle one of these objectives. Their findings, if validated, could significantly advance the mathematical foundation of physics, potentially leading to breakthroughs across various scientific fields.
Their research focuses on unifying three theories of fluid motion that play crucial roles in engineering, from aircraft design to weather forecasting. Until now, these theories were based on unproven assumptions. The new work doesn’t change the theories themselves but provides mathematical support that enhances our confidence in how these equations function.
Each theory looks at fluids from different perspectives. At the microscopic level, fluids are made of moving particles. Newton’s laws explain their motion. However, as we view larger groups of particles, a statistical approach becomes necessary. Ludwig Boltzmann developed the Boltzmann equation in 1872 to handle this by predicting the average behavior of particles rather than tracking each one.
As we zoom out even further, we see fluids as continuous substances, described by the Euler and Navier-Stokes equations. Each perspective adds layers to our understanding of fluid dynamics, and ideally, they should connect logically. Hilbert believed that complete theories should follow mathematical rules that span different scales—from the smallest particles to entire systems.
Bridging these theories has been a tough nut to crack, but the recent paper suggests a breakthrough. The researchers followed a three-step process: deriving the macroscopic theory from the mesoscopic one, the mesoscopic from the microscopic, and then linking them into a comprehensive explanation. This unification could validate different theoretical approaches and strengthen our grasp of fluid dynamics.
The team’s work builds on decades of prior research but addresses a significant dilemma: previous methods often relied on simplified conditions. Their breakthrough relies on a deep dive into how particle interactions evolve over extended periods. They found that even when considering many particle collisions, the cumulative effects can remain small enough to produce a recognizable statistical behavior.
If their findings hold up, we might see a major leap toward solving Hilbert’s challenges. New perspectives may pave the way for additional advancements in physics.
This work reminds us of the essential link between mathematics and the physical world. Homing in on these connections can lead to new discoveries and a deeper understanding of the universe.
For more information on this ongoing research, refer to their paper on arXiv.