Researchers at Stevens Institute of Technology have applied a 350-year-old theorem originally used to describe the behavior of pendulums and planets to uncover new properties of light waves.

Ever since Isaac Newton and Christian Huygens debated the nature of light in the 17th century, the scientific community has grappled with the question: Is light a wave, a particle, or both at the same time at the quantum level? . Now, researchers at the Stevens Institute of Technology have used a 350-year-old mechanical theorem, typically used to describe the motion of large physical objects such as pendulums and planets, to A new relationship has been revealed. The most complex behavior of light waves.

Reveal relationships between light properties

The research, led by Xiaofeng Qian, an assistant professor of physics at Stevens College, and reported in the August 17 online issue of Physical Review Research, shows that the degree of non-quantum entanglement of light waves exists in a direct and complementary relationship. We proved for the first time that it does. It depends on the degree of polarization. As one increases, the other decreases, so the level of entanglement can be directly inferred from the level of polarization, and vice versa. This means that difficult-to-measure optical properties such as amplitude, phase, and correlation (and perhaps even properties of quantum wave systems) can be estimated from something much easier to measure: the intensity of light.

Physicists at Stevens Institute of Technology are using a 350-year-old theorem that explains how pendulums and planets work to uncover new properties of light waves. credit:
Stevens Institute of Technology

“We’ve known for more than a century that light sometimes behaves like waves and sometimes like particles, but reconciling these two paradigms is extremely difficult. We know that,” Chen said. There is a deep connection between the concepts of waves and particles not only at the quantum level but also at the level of classical light waves and point-mass systems. ”

Applying Huygens’ mechanical theorem to light

Qian’s team used a mechanical theorem originally developed by Huygens in his 1673 book on pendulums. This theorem explains how the energy required to rotate an object varies depending on the object’s mass and its axis of rotation. “This is a well-established mechanical theorem that explains how physical systems like clocks and prosthetic limbs work,” Qian explained. “But we were able to show that it can also provide new insights into how light works.”

This 350-year-old theorem describes the relationship between a mass and its rotational momentum. So how does this apply to light, which has no mass to measure? Qian’s team interprets the intensity of light as equivalent to the mass of a physical object, which can be interpreted using Huygens’ mechanical theorem. We mapped those measurements into a coordinate system. “Essentially, we found a way to transform optical systems so that they can be visualized as mechanical systems and described using established physical equations,” he explained. .

Once the researchers visualized light waves as part of a mechanical system, new relationships between wave properties quickly became apparent, such as the fact that entanglement and polarization are clearly related to each other.

“This hasn’t been shown before, but when you map the properties of light onto a mechanical system, it becomes very clear,” Qian says. “What was once abstract becomes concrete. Using mechanical equations, you can literally measure the distance between the ‘center of mass’ and other mechanical points to determine how different properties of light interact with each other. We can show how they are related.”

Elucidating these relationships has important practical implications, as it may allow us to estimate subtle and difficult-to-measure properties of optical systems, and even quantum systems, from simpler and more reliable measurements of light intensity. Qian explained that there is a gender. More speculatively, the researchers’ findings suggest that mechanical systems could be used to simulate and better understand the strange and complex behavior of quantum wave systems.

“It’s still in front of us, but this first study clearly shows that by applying mechanical concepts, we can understand optical systems in entirely new ways,” Qian said. Ta. “Ultimately, this research will help simplify the way we understand the world by allowing us to recognize the essential underlying connections between seemingly unrelated physical laws.”

References: “Bridging coherence optics and classical mechanics: Complementarity of general light polarization entanglement” by Xiao-Feng Qian and Misag Izadi, August 17, 2023. physical review study.
DOI: 10.1103/PhysRevResearch.5.033110