Tag Archives: Christiaan Huygens

350-year-old mechanical theorem reveals new properties of light waves

Caption: Physicists at Stevens Institute of Technology use a 350-year-old theorem that explains the workings of pendulums and planets to reveal new properties of light waves. Credit: Stevens Institute of Technology

An August 21, 2023 news item on phys.org revisits a 350-year old theorem, Note: Links have been removed,

Since the 17th century, when Isaac Newton and Christiaan Huygens first debated the nature of light, scientists have been puzzling over whether light is best viewed as a wave or a particle—or perhaps, at the quantum level, even both at once. Now, researchers at Stevens Institute of Technology have revealed a new connection between the two perspectives, using a 350-year-old mechanical theorem—ordinarily used to describe the movement of large, physical objects like pendulums and planets—to explain some of the most complex behaviors of light waves.

The work, led by Xiaofeng Qian, assistant professor of physics at Stevens and reported in the August 17 [2023] online issue of Physical Review Research, also proves for the first time that a light wave’s degree of non-quantum entanglement exists in a direct and complementary relationship with its degree of polarization. As one rises, the other falls, enabling the level of entanglement to be inferred directly from the level of polarization, and vice versa. This means that hard-to-measure optical properties such as amplitudes, phases and correlations—perhaps even these of quantum wave systems—can be deduced from something a lot easier to measure: light intensity.

An August 20, 2023 Stevens Institute of Technology news release (also on EurekAlert), which originated the news item, notes the research doesn’t resolve the light waves and light particles conundrum but it does reveal something new about it,,

“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,” said Qian “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.” 

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

This 350-year-old theorem describes relationships between masses and their rotational momentum, so how could it be applied to light where there is no mass to measure? Qian’s team interpreted the intensity of a light as the equivalent of a physical object’s mass, then mapped those measurements onto a coordinate system that could be interpreted using Huygens’ mechanical theorem. “Essentially, we found a way to translate an optical system so we could visualize it as a mechanical system, then describe it using well-established physical equations,” explained Qian.

Once the team visualized a light wave as part of a mechanical system, new connections between the wave’s properties immediately became apparent — including the fact that entanglement and polarization stood in a clear relationship with one another.

“This was something that hadn’t been shown before, but that becomes very clear once you map light’s properties onto a mechanical system,” said Qian. “What was once abstract becomes concrete: using mechanical equations, you can literally measure the distance between ‘center of mass’ and other mechanical points to show how different properties of light relate to one another.” 

Clarifying these relationships could have important practical implications, allowing subtle and hard-to-measure properties of optical systems — or even quantum systems — to be deduced from simpler and more robust measurements of light intensity, Qian explained. More speculatively, the team’s findings suggest the possibility of using mechanical systems to simulate and better-understand the strange and complex behaviors of quantum wave systems.

“That still lies ahead of us, but 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,” Qian said. “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.”

Here’s a link to and a citation for the paper,

Bridging coherence optics and classical mechanics: A generic light polarization-entanglement complementary relation by Xiao-Feng Qian and Misagh Izadi. Phys. Rev. Research 5, 033110 Published 17 August 2023

This paper is open access.

Fine watchmaking and nanotechnology team up again

An article by Annie Darling focused on watchmaking and the influence an emerging technology (nanotechnology) can have on this well established field was making the rounds not too long ago (March 6, 2023 on SCMP and March 7, 2023 on Luxury Launches), Note: Links have been removed,

Ever since spring-powered clocks were developed in 15th century Europe, watchmakers have strived to advance the science behind haute horlogerie. First, the mainspring was brainstormed as a mechanism for powering a clock. This apparatus stopped the cracking and weakening of a timepiece’s movement so it could withstand numerous cycles.

Next came the balance wheel, which ensures that movements are able to keep regular time, invented in the mid-17th century by Dutch mathematician and all-round know-it-all Christiaan Huygens. And, of course, any collector worth their salt knows about Abraham-Louis Breguet’s tourbillon that rotates a timepiece’s movement to counter the negative effect of Earth’s gravity.

A lot has changed in the years since, with improved materials and methods allowing for increased miniaturisation, precision and reliability. Now, another wave of innovation is breaking over the field of watchmaking: nanotechnology, the study and manipulation of matter on a near-atomic scale to produce novel structures and materials.

Now watchmakers are starting to take notice, with Hermès incorporating nanotechnology into its novelties for 2023. The Crepuscule – “dusk” in French – is the new iteration of the brand’s emblematic Cape Cod watch. Designed by artist Thanh Phong Lê, the dial features a pensive piece of graphic art depicting a setting sun reflected in water.

One of Switzerland’s leading silicon experts, the Swiss Center for Electronics and Microtechnology, was commissioned to complete the dial, shaped using a silicon wafer just 0.5mm thick. To reach the intensity of colour requested by the maison, a nanotechnology procedure called photolithography was used to transfer Phong Lê’s motif onto the silicon, which was then coated in yellow gold.

Tag Heuer is also experimenting with nanotechnology and has patented a carbon composite hairspring, which comprises of rolled-up sheets [carbon nanotubes; CNTs], each just a single layer of carbon atoms. The hairspring is attached to a watch’s balance wheel to help mechanical timepieces keep accurate time. “Our hairspring is at the very heart of our movements,” says Emmanuel Dupas, director of the Tag Heuer Institute. “We developed our own hairspring based on a carbon nanotube scaffold, which is filled with amorphous carbon. Carbon nanotubes have extremely narrow diameters but can be very long.”

The Hermès Cape Cod Crépuscule depicts a setting sun reflected in water. [Designed by artist Thanh Phong Lê.] Photo: Hermès [downloaded from https://luxurylaunches.com/watches/nanotechnology-fine-watchmaking.php]

it’s a good article if watchmaking and/or luxury products and/or applied nanotechology interests you. Whichever site you choose (March 6, 2023 on SCMP or March 7, 2023 on Luxury Launches), you’ll find more embedded images of watches from different companies.

There’s also this December 29, 2016 posting, “Luxury watches exploit nanocomposite materials,” about an Australian watch company.