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The researchers had to look at light mechanically to begin seeing similarities in properties usually seen in quantum states.

In 1,673, Christiaan Huygens wrote a book on pendulums and how they work. A mechanical theorem mentioned in the book was used 350 years later by researchers at the Stevens Institute of Technology to explain the complex behaviors of light, a university statement said.

Although known to us for eons, humanity has found it difficult to explain the very nature of light. For centuries scientists have been divided on whether to call it a wave or a particle and when there seemed to be some agreement on what light could actually be, quantum physics threw a new curveball by suggesting that it existed as both at once.

People living in dry but foggy areas can benefit from this technology.

Researchers from ETH Zurich have developed a system that captures fog in the atmosphere and simultaneously removes contaminants while running using solar power.

The harvesting and water treatment system consists of a metal wire mesh with a solar-light-activated reactive coating that captures the fog. The droplets of water then trickle down into a container below. The mesh is coated with a mixture of specially selected polymers and titanium dioxide, which acts as a chemical catalyst and breaks down the molecules of the pollutants into harmless particles.

Discover cosmic enigmas: Ohio State’s study on neutrinos and supernovae unveils new insights into the universe’s hidden interactions.

You may have heard of light as both particles and waves, but have you ever imagined the secret dance within? Researchers from the University of Ottawa and Sapienza University in Rome have just uncovered a groundbreaking technique that enables the real-time visualization of the wave function of entangled photons — the fundamental components of light.

Imagine choosing a random shoe from a pair. If it’s a “left” shoe, you immediately know the other shoe you’ve yet to unbox is meant to go on your right foot. This instantaneous information is certain whether the shoe box is within hand’s reach or 4.3 light-years away on some planet in the Alpha Centauri system.

This analogy, though not perfect, captures the essence of quantum entanglement. At its core, quantum entanglement refers to the phenomenon where two or more particles become deeply interconnected in such a way that their properties become correlated, regardless of the spatial separation between them. This means that the state of one particle instantly influences the state of another, even if they are light-years apart.

A new robotic platform developed at the University of Chicago can adapt to its surroundings in real time for applications in unfamiliar environments.

The platform, dubbed the Granulobot, consists of many identical motorized units each a few centimeters in diameter. The units are embedded with a Wi-Fi microcontroller and sensors and use magnets to engage other units.

Continue reading “Shape-Shifting Robot Swarms Self-Assemble, Adapt to the Unfamiliar” »

The ancient Greek philosopher Aristotle wrote in his manuscript on Physics 2,373 years ago: “If everything that exists has a place, place too will have a place, and so on ad infinitum.” Is the notion of space being continuous ‘without limit’ justified?

Before elementary particles were discovered, water was thought to be a continuous fluid. This is a good approximation on large scales but not on molecular scales where the interactions among elementary particles matter.

Similarly, spacetime has been thought to be a continuum since ancient times. While this notion appears consistent with all experimental data on large spatial or temporal scales, it may not be valid on tiny scales where quantum effects of gravity matter. An analogy can be made with the illusion of a movie which appears continuous when the frame rate is high enough and the spatial pixels are small enough for our brain to process the experience as seamless. Since our brain is made of elementary particles, the temporal and spatial resolution by which it senses reality is coarser by many orders of magnitude than any fundamental scale by which spacetime is discretized.

While optics and mechanics are two distinct branches of physics, they are connected. It is well known that the geometrical/ray treatment of light has direct analogies to mechanical descriptions of particle motion. However, connections between coherence wave optics and classical mechanics are rarely reported. Here we report links of the two through a systematic quantitative analysis of polarization and entanglement, two optical coherence properties under the wave description of light pioneered by Huygens and Fresnel. A generic complementary identity relation is obtained for arbitrary light fields. More surprisingly, through the barycentric coordinate system, optical polarization, entanglement, and their identity relation are shown to be quantitatively associated with the mechanical concepts of center of mass and moment of inertia via the Huygens-Steiner theorem for rigid body rotation.

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 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.

“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.”

Researchers at the University of Ottawa, in collaboration with Danilo Zia and Fabio Sciarrino from the Sapienza University of Rome, recently demonstrated a novel technique that allows the visualization of the wave function of two entangled photons, the elementary particles that constitute light, in real-time.

Using the analogy of a pair of shoes, the concept of entanglement can be likened to selecting a shoe at random. The moment you identify one shoe, the nature of the other (whether it is the left or right shoe) is instantly discerned, regardless of its location in the universe. However, the intriguing factor is the inherent uncertainty associated with the identification process until the exact moment of observation.

The wave function, a central tenet in quantum mechanics, provides a comprehensive understanding of a particle’s quantum state. For instance, in the shoe example, the “wave function” of the shoe could carry information such as left or right, the size, the color, and so on.