Finding Paths of Least Action with Gradient Descent
Gradient descent, a fundamental optimization technique in machine learning, has found a novel application in physics through the concept of action minimization. This approach leverages the principle of least action, a cornerstone of theoretical physics, to simulate physical systems.
In physics, the action is a scalar quantity that describes the evolution of a system over time. The principle of least action states that the actual path taken by a physical system is the one that minimizes the action. Traditionally, this minimization is performed analytically using tools like the Euler-Lagrange equation to derive equations of motion.
Recent research, such as the paper titled "Nature's Cost Function: Simulating Physics by Minimizing the Action", proposes a computational approach to action minimization. Instead of analytical methods, the action is discretized and minimized using gradient descent. This technique has been successfully applied to simulate various physical systems, demonstrating results nearly identical to ground-truth dynamics.
This approach offers several advantages:
As discussed in "Connecting Gradient Descent to Physically Observed Solutions", gradient descent and its variants, such as weight decay, implicitly bias solutions toward minimal-energy configurations. This aligns with physical observations in equilibrium situations, where systems naturally tend to lower energy states.
The integration of gradient descent into action minimization represents a powerful synergy between machine learning and physics. By leveraging computational techniques, researchers can simulate physical systems with greater efficiency and explore new frontiers in theoretical and quantum physics.