Title: Researchers Discover New Insights About Light’s Nature Using 350-Year-Old Theorem
Subtitle: Stevens Institute of Technology scientists unveil the connection between wave and particle concepts through the application of a mechanical theorem
Date: August 17, 2023
Researchers at the Stevens Institute of Technology have made a groundbreaking discovery by applying a centuries-old mechanical theorem to uncover new insights about the nature of light. By interpreting light’s intensity as equivalent to physical mass, the team was able to map light onto a system where established mechanical equations could be applied. This approach revealed a direct correlation between the degree of non-quantum entanglement and the degree of polarization in a light wave.
The work, led by Xiaofeng Qian, Assistant Professor of Physics at Stevens, sheds light on the long-standing debate between the wave and particle nature of light. The scientific community has grappled with this question for centuries, and this research provides a new connection between the two perspectives. The team used a 350-year-old mechanical theorem, primarily used to describe the behavior of large, physical objects like pendulums and planets, to explain complex behaviors of light waves.
The study, reported in Physical Review Research, also revealed for the first time that the level of non-quantum entanglement in a light wave is directly related to its level of polarization. As one rises, the other falls, enabling the degree of entanglement to be deduced from the level of polarization, and vice versa. This breakthrough opens up new possibilities for measuring optical properties such as amplitudes, phases, and correlations through simpler light intensity measurements.
Xiaofeng Qian explained, “We’ve known for over a century that light sometimes behaves like a wave and sometimes like a particle, but reconciling those two frameworks has proven extremely difficult. Our work doesn’t solve that problem, but it does show that there are profound connections between wave and particle concepts not just at the quantum level, but at the level of classical light-waves and point-mass systems.”
The team applied a mechanical theorem developed by Christiaan Huygens in 1673, which describes how the energy required to rotate an object varies based on its mass and the axis around which it turns. Although light has no mass to measure, Qian’s team interpreted its intensity as the equivalent of a physical object’s mass. By mapping these measurements onto a coordinate system, they were able to apply Huygens’ mechanical theorem. This allowed them to describe light using well-established physical equations.
Once the light wave was visualized as part of a mechanical system, previously unseen connections between its properties emerged. A clear relationship between entanglement and polarization was discovered, which had not been shown before. Qian explained that by applying mechanical equations, it became possible to measure the distance between the “center of mass” and other mechanical points, revealing how different properties of light relate to each other.
The findings of this research have significant practical implications. They can simplify the understanding of subtle and hard-to-measure properties of optical systems and quantum systems by deducing them from more straightforward and robust measurements of light intensity. Additionally, the research suggests the possibility of using mechanical systems to simulate and gain better insights into the complex behaviors of quantum wave systems.
Xiaofeng Qian concluded by saying, “With this first study, we’ve shown clearly that by applying mechanical concepts, it’s possible to understand optical systems in an entirely new way. Ultimately, this research is helping to simplify the way we understand the world by allowing us to recognize the intrinsic underlying connections between apparently unrelated physical laws.”
The study, titled “Bridging coherence optics and classical mechanics: A generic light polarization-entanglement complementary relation,” was authored by Xiaofeng Qian and Misagh Izadi. It was published in the journal Physical Review Research on August 17, 2023.